The State of Western Australia v Rasmussen - [2020] WADC 162

JURISDICTION : DISTRICT COURT OF WESTERN AUSTRALIA
IN CRIMINAL

LOCATION:   PERTH
CITATION:   THE STATE OF WESTERN AUSTRALIA -v- RASMUSSEN [2020] WADC 162
CORAM:   SWEENEY DCJ
HEARD:   21 JULY 2020
DELIVERED          :   18 DECEMBER 2020
FILE NO/S:   IND 729 of 2017
BETWEEN:   THE STATE OF WESTERN AUSTRALIA

AND
JUSTIN BARRY THEODORE RASMUSSEN

Catchwords:

Expert evidence - Failure to identify factual basis - Failure to reveal reasoning - Expertise - Automatism

Legislation:

Nil

Result:

Expert reports ruled inadmissible

Representation:

Counsel:

The State of Western Australia	:	Ms A L Forrester SC & Ms J B Winter
Accused	:	Ms J T Fisher

Solicitors:

The State of Western Australia	:	State Director of Public Prosecutions
Accused	:	Justine Fisher Barristers & Solicitors

Case(s) referred to in decision(s):

HG v The Queen (1999) 197 CLR 414
J (1994) 75 A Crim R 522
Makita (Australia) Pty Ltd v Sprowles [2001] NSWCA 305
McNeil v Commissioner of Taxation [2003] FCA 958
R v Falconer [1990] HCA 49; (1990) 171 CLR 30
R v Turner [1975] QB 834
SWD v The State of Western Australia [2017] WASCA 39
Sydneywide Distributors Pty Ltd v Red Bull Australia Pty Ltd (2002) 55 IPR 354
The State of Western Australia v Silich [2011] WASCA 135
Town of Mosman Park v Tait [2005] WASCA 124

SWEENEY DCJ:

Introduction

Mr Rasmussen stands charged with one count of unlawfully doing grievous bodily harm to another, contrary to s 297 Criminal Code (WA). This matter is listed for trial to commence on 30 January 2021. The defence has served upon the prosecution an expert report from Professor Paul W Skerritt, psychiatrist, dated 20 January 2020 and, following objection to that evidence, a supplementary report dated 13 April 2020. The State objects to the evidence of Professor Skerritt in its entirety.
This ruling is based upon the papers. At the directions hearing, defence counsel indicated that she was content to rely upon the two reports and would not be obtaining any further report from Professor Skerritt, however made him available for cross-examination, an offer the prosecution declined to take up.
For the reasons which appear below, I rule Professor Skerritt's proposed evidence inadmissible.

Facts of alleged offence

The State's case against the Accused appears from its amended statement of material facts dated 19 July 2017 (this matter has a protracted history and the January 2021 trial is the fifth such listing). While reference is made to an 'accused' Lehman, proceedings were discontinued against him in October 2018:
The complainant in this matter at the relevant time was 28 years of age, is male, 175 centimetres tall and medium build. The accused RASMUSSEN was 45 years of age, is male, 185 centimetres tall and solid build. The accused LEHMAN was 41 years of age, is male, 185 centimetres tall and solid build.
At about 8pm on Saturday, 1 October 2016, the accused RASMUSSEN was at 8 Harrison way, Calista. The complainant, who resides at the address, was celebrating his birthday with numerous other people. RASMUSSEN was in the rear yard and became involved in a verbal argument with another partygoer and was asked to leave by the complainant. RASMUSSEN and a female moved to the front of the property and at some point, within the hearing of those at the party, RASMUSSEN made a telephone call to co-accused LEHMAN, indicating that there were six aggressive males and LEHMAN should come to the address.
A short time later co-accused LEHMAN attended the address. The complainant saw RASMUSSEN and LEHMAN and walked to the front of the property whilst holding a metal pole. LEHMAN returned to his vehicle, armed himself with a machete and walked towards the complainant. LEHMAN confronted the complainant in the roadway at the end of his driveway. He punched the complainant causing the complainant to drop the pole.
RASMUSSEN picked up the pole and struck the complainant to the right hip and then struck the complainant a second time to the left temple area of his head. The complainant fell to the ground unconscious. RASMUSSEN and LEHMAN ran to the nearby vehicles and left the area.
The complainant suffered a fractured cheek, large laceration to the left temple area and swelling to his left eye causing pressure to build up behind the eye, endangering the eye.

Accused's version of events in interview

In his interview with police at South Hedland police station on 3 October 2016 (the unedited version for the purposes of this decision) the Accused told police that the complainant came towards his companion, Shane Lehman, swinging his pole a couple of times like he was trying to take Lehman out with it. The Accused said that he does not know how - whether Lehman moved back or the guy moved forward or both - but the Accused found himself at the side of the complainant, and he saw the pole 'come up like that':
so I just turned, I don't even, I can't even really recall what I've done, whether I've grabbed it like that, whether I've grabbed it like that. I can't remember hold - holding it and dropping it or throwing it. But, um, yeah. I've got a little bruise on me fucking thumbnail, just fuck all, and when I got home I am going like that, and, so enough of something where something's hit, hit my thumb, you know. So, um, and he's hit the fucking deck, you know. I thought I've done it … I really thought I've done it, you know and because, then Shane was saying, 'he fucking hit the deck hard, bro' and I'm going 'fuck, fuck, fuck', you know. But he, he goes, 'no, bro'. He goes, 'it was one woman pushing him, then another woman pushed him', you know. So I'm not sure what I've, what's happened when I've, ah, whether I've grabbed it like that, whether I've grabbed it like that, but, you know, you can see just here on the side of the thumb there is a small bruise, you know …. It's fuck all but, you know, I could feel that something's impacted my hand, you know. Um, and he goes, 'No bro'. He goes 'One', he goes 'I saw it clear as day'. And I even said to him, I said 'You saw more than fucking I did because I, I, it's just like a blur to me what, what had gone on'. He said, 'Plain as day, bro'. He goes, he goes 'One woman come and shoved him, then another one shoved him, and he went on his ass, bang. He went down hard and hit his head' … So that, I'm saying, is what I've been told. I didn't see, I can't say I saw that with any clarity. I didn't see it.
The Accused went on to say that he had been whacked on the hand by the pole and had certainly grabbed hold of the complainant's pole and pushed it away with a lot of force:
Because Shane's about to get hit in the head with this pole, man, you know, and it's not going to, it's not going to be a bruise, you know. Yeah.
The interviewing officer then confirmed with the Accused that his next memory, discounting what he had been told by others, is that the complainant had gone down on the road hard. The Accused responded:
He's on the ground. That's right, yeah … The pole's not in my hand at this stage.
Asked by the interviewing officer where the pole was at that stage, the Accused responded:
I'm, I don't know. I really don't know. That's why I, I can't remember, at no point, I can say, I've got a conscious, that it's going, I'm holding the fucking pole, you know, or I threw it or dropped it. I, oh, I don't know, but he is, the guy's on the fucking ground, you know… It's just, ah, it happened like that, you know.
The Accused said that he did not actually remember hitting the complainant, but when asked if he remembered grabbing it, responded:
it, it wouldn't, it wouldn't have s-, well, ah, I, I, I (indistinct) it's pri-, it wasn't like I was trying not to, but I wasn't trying to either, you know. It's, ah, I think it was to get the fucking pole, you know. It's, um, to be honest, at that stage, ah, my, his welfare, I didn't give, ah, well, it fucking wasn't my concern … It was fucking to stop him, Shane getting hit in the fucking head with this fucking pole.
The Accused confirmed that he remembered grabbing the pole, and then he remembered having nothing in his hands and the complainant being on the ground. He said he does not recall actually hitting him. He denied going into a rage because he said, afterwards, he was not even angry. He said:
It's actually difficult for me to get angry on that Seroquel stuff. It's, um, um, but, um, why I've got such, ah, a poor recollection of exactly what's happened, I don't know. I'm going to put down to adrenaline, you know. It's… And, and, and it being dark, you know, but, yeah.
A little later he said he assumed that he had done it
because I was the one that grabbed the pole and to me I was the last per -, was, because I didn't see him. So to me I was the only person that had any force or contact with the guy and so, yeah … I can't even tell you if I swung it away or if I, I didn't pull it this way. It's, I've definitely gone like, like that. Whether it was like that or, it was that motion so it's, um, I didn't feel a, I certainly haven't grabbed it or something and then felt the impact, you know. It's, but, again, I don't even remember feeling what the texture of the pole, or the weight of it or any-, anything, so…

Legal principles in relation to 'sane' automatism and s 23A(2)

Subject to the law of negligence, a person is not criminally responsible for an act which occurs independently of the exercise of his will: s 23A(2) Criminal Code. Section 23A is not concerned with the consequences of an act (as to which see s 23B) but only whether the act itself was willed. In the absence of some contrary evidence, when an apparently conscious person does an act, there is a presumption that the act was willed: R v Falconer [1990] HCA 49; (1990) 171 CLR 30 [9] (Mason CJ, Brennan and McHugh JJ). If there is evidence, however, that the act did occur independently of the exercise of the Accused's will, then it is for the State to prove beyond reasonable doubt that the act was willed. If the act was involuntary, the Accused is entitled to an acquittal.
'Automatism' is a state in which a person's acts occur independently of the exercise of his will.
But if that automatism is the result of a defect or disease of the mind, or unintentional intoxication or stupefaction, then s 27 Criminal Code provides the appropriate defence and s 23A does not apply.
If involuntariness proceeds from 'such a state of mental impairment as to deprive him of the capacity to understand what he is doing, or of capacity to control his actions, or of capacity to know that he ought not to do the act' (see s 27 Criminal Code) then it raises a qualified defence entitling the Accused to a qualified acquittal on account of unsoundness of mind, the implication of which is that the Accused then falls to be dealt with pursuant to the Criminal Law (Mentally Impaired Accused) Act 1996 (WA). 'Unsoundness of mind' comprehends mental disease, natural mental infirmity and a mind disordered by intoxication or stupefaction: R v Falconer (Mason CJ, Brennan and McHugh JJ) [18], but does not encompass intentional intoxication or stupefaction: s 28 Criminal Code.
By contrast, 'sane automatism' (also referred to as 'non‑insane automatism'), to which s 23A does apply, refers at law to a transient inability to control one's actions resulting from the reaction of a sound mind, possessed of the strength possessed by an ordinary person, to physical or psychological trauma (Falconer [28] (Mason CJ, Brennan and McHugh JJ)):
In a given case, if the psychological trauma causes a sound mind, possessed of the requisite standard of strength, to malfunction only transiently so as to produce the effects mentioned in the M'Naghton Rules or in s 27 of the Code, the malfunction cannot be attributed to mental infirmity but to 'the nature of man': that is to say, a malfunction which is transient and not prone to recur and to which the mind of an ordinary person would be subject if exposed to the same psychological trauma is neither a mental disease nor a natural mental infirmity. It is neither an instance of unsoundness of mind under the Code nor an instance of insanity at common law …
Once the issue of automatism is raised, it is for the State to prove that the Accused's act was voluntary. However the issue, once raised, may also raise a qualified defence of unsoundness of mind where the evidence is not clear as to whether the mental malfunction was 'sane' automatism or otherwise (Falconer (Mason CJ, Brennan and McHugh JJ)):
29… When an accused raises automatism and assigns some malfunction of the mind is its cause, he raises a defence of unsoundness of mind or insanity unless the malfunction of his mind was (1) transient (2) caused by trauma, whether physical or psychological, which the mind of an ordinary person would be likely not to have withstood and (3) not prone to recur. A malfunction of the mind other than a malfunction which satisfies those exempting qualifications amounts to a disease of the mind, or a mental disease or natural mental infirmity. As an accused bears no ultimate onus of proving that his act was not willed, in theory an accused may raise the issue of non-insane automatism on the evidence and claim to be acquitted outright unless the prosecution disproves the issue. But in practice an accused does not raise non-insane automatism by raising automatism based merely on mental malfunction. Prima facie, mental malfunction is the consequence of mental infirmity and, until it to be proved that a particular instance of mental malfunction satisfies the exempting qualifications, mental malfunction must be treated as a consequence of mental infirmity.
30It follows that, unless and until the automatism on which an accused relies is proved to be merely a transient mental malfunction of his otherwise sound mind caused by trauma and that the malfunction is not likely to recur, both s. 26 of the Code and the common law preclude consideration of automatism for the purpose of determining whether the incriminated act was willed or voluntary. If an accused proves on the balance of probabilities that he was acting as an automaton when the act was done by reason of mental malfunction but fails to prove that his mental malfunction satisfied the exempting qualifications, he is entitled to be acquitted on account of unsoundness of mind or on the ground of insanity. However, if he proves that his mental malfunction satisfied the exempting qualifications, he is entitled to an outright acquittal. … In some instances (for example, concussion caused by physical trauma), the accused may be able to prove on the balance of probabilities at the outset that, if there were any malfunction of the mind which deprived him of the capacity to know the nature and quality of his act or to control his actions, the malfunction satisfied the exempting qualifications and therefore did not flow from an underlying mental infirmity. In such a case, the onus shifts to the prosecution to prove beyond reasonable doubt that there was no malfunction or that it did not affect the accused's control of his actions. But in cases where the accused, claiming to have acted as an automaton by reason of a transient malfunction precipitated by psychological trauma, seeks to take the malfunction out of the prima facie classification of unsoundness of mind or insanity, the onus of proving the exempting qualifications can hardly be discharged before the malfunction itself is proved. Where the accused succeeds in proving that the relevant act was done in a state of automatism by reason of a malfunction of his mind, he is at risk of a qualified verdict of acquittal … unless and until he succeeds in discharging the onus of proving the exempting qualifications on the balance of probabilities.
31A mental malfunction which deprives an accused of the capacity to control his actions (or to know the nature and quality of his act) and which does not fulfil the exempting qualifications amounts to unsoundness of mind (under the Code) or insanity (at common law) …

Materials provided to Professor Skerritt by the defence for his opinion

The Accused's legal representatives consulted Professor Skerritt by way of email dated 8 January 2020. The request was brief. No assumed set of facts or instructions was presented to Professor Skerritt for his opinion. Rather, he was provided with the prosecution brief - including, presumably, the Accused's interviews - and his opinion was requested as to whether the Accused met the criteria for post-traumatic stress disorder (PTSD), whether PTSD was likely 'a contributing factor to Mr Rassmussen assaulting the complainant', and whether the act of assaulting the complainant 'satisfies Non-insane automatism and was an unwilled act and whether the Accused was likely to have dissociated at the time'.
From his report it appears that Professor Skerritt was also provided with the transcript of a hearing before Bowden DCJ on 11 November 2019 in which his Honour canvassed, amongst other things, the principles in relation to the distinction between a qualified acquittal on account of unsoundness of mind pursuant to s 27 of the Criminal Code and an outright acquittal in accordance with s 23A(2) on the basis of sane automatism.
Professor Skerritt was also provided with two prior psychiatric reports, obtained for the purposes of sentencing proceedings prior to the Accused's successful change of plea application in March 2019. The professor's own research produced, it seems, a third psychiatric report. Such evidence would be inadmissible unless the defence were to call the authors of those reports to testify at trial. It is not the intention of the defence to do so, and therefore those reports cannot provide an admissible basis for any of Professor Skerritt's opinions. Counsel both agreed that there was no need for me to have regard to those reports for the purposes of this decision. Consequently, I have positively stayed away from them in order to better analyse the sufficiency of the factual basis of the professor's reports.
Professor Skerritt saw the Accused in consultation on 15 January 2020.

Conclusions reached by Professor Skerritt in his first report

In his first report of 20 January 2020, Professor Skerritt annexed the diagnostic criteria for PTSD to be found in Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association (DSM 5) and concluded that the Accused meets some, but not all, of the criteria for PTSD, and that some of his symptoms may also be explained by anxiety and depression. He also commented that PTSD itself 'would not be considered relevant to that disassociation in the sense of the alleged offences although it is part of the criteria to do with the traumatic experiences'.
He agreed with the diagnosis of others that the Accused has Attention Deficit Hyperactivity Disorder (ADHD).
He found that the Accused has a mood disorder which is bipolar in nature.
He found that the Accused suffers from a generalised anxiety disorder as well as a panic disorder, and also suffers from depression, implying that he found the Accused to suffer from a major depressive disorder.
It is necessary to quote Professor Skerritt in full as to his conclusions concerning automatism. Having referred to his diagnosis that the Accused suffers from anxiety disorders as well as the other diagnoses referred to above, Professor Skerritt continued:
In the midst of these diagnostic combinations it is the anxiety disorders that are typically associated with the defence of disassociation where the brain copes with the overwhelming fear by switching off the stream of consciousness and in such circumstances automatic behaviour, that is not under the exertion of the will, can occur.
I think that the phenomena of disassociation and automatism generally are more prone to complications in the legal understanding than the psychiatric one. In the case of Mr Rasmussen we have a fearful situation threatening violence in the presence of members of a 'bikie gang', his mounting anxiety and switching off so that he did not remember anything until the crisis had passed. There is a history that such occurrences have happened previously and he had a clear diagnosis of the anxiety disorders. Bearing in mind his Honour's caution that a gap in memory does not give a diagnosis of automatism, I think that this history of a fearful situation with mounting tension, in a person with a history of anxiety disorder suddenly switching off, does provide sufficient evidence that he was in a dissociated state, or automatism in legal terms.
The question is then whether his state of automatism was 'sane' or 'insane'. These are terms which have long been abandoned in psychiatry and when they persist in a legal sense usually imply illnesses designated by psychiatry as psychotic. That was not the case here. If the disassociation is a response to an illness of anxiety rather than a non-pathological state, that is proceeding from a mental illness if not a psychotic one, it would appear that the law would describe this as insane automatism if my understanding is correct, as unwilling as I am to intrude on the legal decision-making. With the first two criteria above, he was mostly in a state of psychological trauma which would produce a state of fear in a normal person but in his case went further than that and provoked symptoms of a pre-existing illness.
That leaves the question of the proneness of such disassociation to recur … The best way of predicting the future is to look at the past and the history suggested that there had been other episodes of anxiety with the defence of disassociation. I might agree with my colleague, however, that it is not likely to recur under these circumstances.
He has left the 'bikie' organisation which provoked the anxiety at least on this occasion. A positive feature of his personality is his ability to work and he is employed in a regular FIFO job indicating a general settling of his mental state.
He has successfully embarked on several trade qualifications. He is under regular psychiatric treatment which has produced some benefit by his own account from the anxiety with the approach of two different medications …
With all of these factors I think that his proneness to recur can be regarded as minimal.

Conclusions reached by Professor Skerritt in his second report

In his supplementary report of 13 April 2020, Professor Skerritt provided some further explanation of his conclusion in relation to dissociation. Again, it is important to quote him in full (spelling errors corrected):
There is mention of the facts relating to the circumstances of the alleged offence. I was not really given the task of considering these but rather to look at the mental state of Mr Rassmussen at the time. I was quite satisfied that it was a very ugly scene in which members of bikie gangs (related to me as such by Mr Rassmussen) were involved and that was enough for me to indicate the fearful nature of his reaction with respect to the possibility of disassociation and defence of automatism.
In the fourth (unnumbered) page of the DPP letter the three criteria described by his Honour from the case of Falconer were discussed. I have to say that my own explanation of the circumstances was considerably clearer than that in paragraphs a) and b) of the letter. To put it more simply we have a situation of mounting tension in a fearful circumstance allegedly resulting in the person's brain 'switching off' as a defence against the fear. This is known as disassociation. The question then is whether this is related to a mental illness or might have occurred as a normal defence to an abnormal circumstance.
If the panic that was described in his life before was provoked in the circumstances, the legal question is whether this constitutes 'insane' automatism. My suggestion was that this was such a fearful situation and there was not a very good description of the nature of the anxiety experienced before the switching off process, that he [sic: his] could be considered to be a reaction that any normal person might have. When I review my casenotes I had great difficulty extracting a description of his feeling immediately before the supposed association [sic: dissociation]. He described a great deal of fear and on pressing used the word 'panic' but I was not convinced that the word reflected his previous experience of so-called panic disorder.
The last criterion is perhaps the most difficult requiring doctors to perform the task often expected of them but not other human beings, of telling the future. I discussed this in the last couple of paragraphs of my letter to which I cannot add.

Legal principles for admissibility of expert opinion evidence

In the decision of Makita (Australia) Pty Ltd v Sprowles [2001] NSWCA 305, Heydon JA, in an oft-quoted passage [85], stated:
In short, if evidence tendered as expert opinion evidence is to be admissible, it must be agreed or demonstrated that there is a field of 'specialised knowledge'; there must be an identified aspect of that field in which the witness demonstrates that by reason of specified training, study or experience, the witness has become an expert; the opinion proffered must be 'wholly or substantially based on the witness's expert knowledge'; so far as the opinion is based on facts 'observed' by the expert, they must be identified and admissibly proved by the expert, and so far as the opinion is based on 'assumed' or 'accepted' facts, they must be identified and proved in some other way; it must be established that the facts on which the opinion is based form a proper foundation for it; and the opinion of an expert requires demonstration or examination of the scientific or other intellectual basis of the conclusions reached: that is, the expert's evidence must explain how the field of 'specialised knowledge' in which the witness is expert by reason of 'training, study or experience', and on which the opinion is 'wholly or substantially based', applies to the facts assumed or observed so as to produce the opinion propounded. If all these matters are not made explicit, it is not possible to be sure whether the opinion is based wholly or substantially on the expert's specialised knowledge. If the court cannot be sure of that, the evidence is strictly speaking not admissible, and, so far as it is admissible, of diminished weight. And an attempt to make the basis of the opinion explicit may reveal that it is not based on specialised expert knowledge, but, to use Gleeson CJ's characterisation of the evidence in HG v R (1999) 197 CLR 414, on 'a combination of speculation, inference, personal and second-hand views as to the credibility of the complainant, and a process of reasoning which went well beyond the field of expertise'.
The evidence in that case was subject to s 79 of the Evidence Act 1995 (NSW) which provided in effect that opinion evidence could be admitted to prove the existence of a fact if the person expressing the opinion had specialised knowledge based on his training, study or experience and the opinion was wholly or substantially based on that knowledge. The section finds no equivalent in the Evidence Act (WA), but in this State, the principles expressed by Heydon JA in Makita (Australia) Pty Ltd v Sprowles were similarly encapsulated in Town of Mosman Park v Tait [2005] WASCA 124 [63] by McLure JA:
Firstly, the subject matter must be of such a nature as to require a sufficient degree of specialised knowledge to render expert evidence admissible. Secondly, the witness must have relevant expertise in the area. Thirdly, the expert must either prove by admissible means the facts upon which the opinion is based or explicitly state the assumptions as to the facts on which the opinion is based. Fourthly, the process of inference that leads to the opinion must be stated or revealed in a way that enables the conclusion to be tested and a judgement made about its reliability.
The principles set down by Heydon JA have been described as 'a counsel of perfection' by Branson J in the Federal Court in Sydneywide Distributors Pty Ltd v Red Bull Australia Pty Ltd (2002) 55 IPR 354 at [7] while, in the same decision, Weinberg and Dowsett JJ stated (emphasis added):
87The use of the phrase 'strictly speaking' in the last sentence should not be overlooked. It may well be correct to say that such evidence is not strictly admissible unless it is shown to have all of the qualities discussed by Heydon JA. However many of those qualities involve questions of degree, requiring the exercise of judgement. For this reason it would be very rare indeed for a court at first instance to reach a decision as to whether tendered expert evidence satisfied all of his Honour's requirements before receiving it as evidence in the proceedings. More commonly, once the witness's claim to expertise is made out and the relevance and admissibility of opinion evidence demonstrated, such evidence is received. The various qualities described by Heydon JA are then assessed in the course of determining the weight to be given to the evidence. There will be cases in which it would be technically correct to rule, at the end of the trial, that the evidence in question was not admissible because it lacked one or other of those qualities, but there would be little utility in so doing. It would probably lead to further difficulties in the appellate process.
The above passage, however, suggests that the position has not been reached where any evidence purporting to be expert evidence will be admitted without at least satisfying the basic requirements of relevance and expertise. In addition, within the context of agreeing generally with Weinberg and Dowsett JJ, Branson J regretted that the practice of the voir dire to determine admissibility (emphasis added):
9… has come to be regarded as of little practical value where the judge, and not a jury, is the trier of facts … For this reason, it may prove to be the case that evidence ruled admissible as expert opinion will later be found by the trial judge to be without weight for reasons that, strictly speaking, might be thought to go to the issue of admissibility (eg that the witness's opinion is expressed with respect to a matter outside his or her area of expertise or is not wholly or substantially based on that expertise).
That distinction between trial by judge and trial by jury is a significant one. Although, in a criminal trial involving expert evidence, the jury will often be instructed that the fact that evidence has been given by an expert witness does not mean they are bound to accept it (with variations on the appropriate direction depending on the issues in the case), it would be inappropriate for expert evidence to be placed before a jury that falls well short of what is required of an expert witness, leaving a trial judge in the invidious position of potentially directing the jury to disregard the evidence entirely, with the attendant risks of commenting on the facts and evidence.
HG v The Queen (1999) 197 CLR 414, concerned an appeal against conviction on two counts of sexual intercourse with a child under the age of 10 years. The trial judge had ruled inadmissible the opinion of a psychologist sought to be called on the part of the defence. That psychologist was expected to testify that the child complainant - who was 10 years old when she disclosed to her sceptical mother that she had been abused by the accused (her mother's partner) between the ages of 8 and 9 - had been sexually abused during the single month, some 5 years earlier, when she had stayed with her now deceased father, had buried the memory of that abuse which had then been recently revived by a stranger danger class and had then distorted the memory into a detailed accusation of chronic abuse by the accused. Abuse by her father was something the child had never complained of, and was supported only by the most speculative evidence of sleep disturbance and the psychologist's view that the complainant's account of the alleged offences contained inconsistencies.
At trial, the so-called expert opinion evidence had been ruled inadmissible as infringing a prohibition on evidence of prior sexual experience as that was how the parties had confined their argument before the trial judge, but the trial judge's initial reaction was to express reservations about whether it was admissible as opinion evidence in any event. An appeal was dismissed by the Supreme Court and, on appeal to the High Court, broader issues of admissibility were also considered. Gleeson CJ stated:
44This was not a trial by jury, but in trials before judges alone, as well as in trials by jury, it is important that the opinions of expert witnesses be confined, in accordance with s 79, to opinions which are wholly or substantially based on their specialised knowledge. Experts who venture 'opinions' (sometimes merely their own inference of fact), outside their field of specialised knowledge may invest those opinions with a spurious appearance of authority, and legitimate processes of fact-finding may be subverted. The opinions which Mr McCombie was to be invited to express appear to provide a good example of the mischief which is to be avoided.
Plainly that was a quite extraordinary scenario and, had such evidence been placed before the jury, it is difficult to see how any direction given by a trial judge could have cured the unfairness to the prosecution and the general subversion of the fact-finding process by the jury.
There is a need to ensure, prior to expert opinion evidence being led before a jury, that it accords at least substantially with the basic requirements for admissibility and that the party against whom it is led has been provided with at least substantial disclosure to avoid an unfair trial through subversion of the fact-finding process.
The distinction between inadequacies in the proposed evidence which go to admissibility and those which go to weight appears to me to be one of degree, with the caveat that evidence which cannot rationally affect the assessment of the probability of the existence of a fact in issue is inadmissible because it is irrelevant.
If the inadequacies in the proposed evidence are substantial, if the evidence is likely on account of those inadequacies to work an incurable unfairness to the party against whom it is sought to be led, or will tend to mislead the jury, or leave the jury in a position of being unable to assess what weight to put on the opinion or identify what the opinion actually is, then such evidence should not be put before a jury.
That does not mean there is a differing test or standard of proof for admissibility of expert evidence in a criminal trial, or in a criminal trial to be held before a jury. A party does not face a higher burden in a criminal trial to be held before a jury of establishing that the evidence it wishes to lead is relevant expert evidence and admissible. But there is not the luxury, if that be what it is, of determining after the fact that the evidence did not satisfy the basic requirements, at least substantially enough to justify its admission, and nor is there the same emphasis on pleadings and a determination by the parties as to the matters in issue as there is in a civil case.
I will deal with the principles in relation to the expertise of the witness under a separate heading.

Does Professor Skerritt either prove the facts upon which his opinion is based or reveal the factual assumptions underpinning his opinion?

In Makita, Heydon JA at [62] referred to a series of cases illustrating the undesirability of allowing an expert witness to give a general opinion without either proving or, alternatively, identifying the facts underlying the opinion, leaving the opposing party with
… two choices. The first is to cross-examine in the dark, with the perils which usually face journeys into darkness … The second is not to cross‑examine, and run the risk of the court attaching weight to the opinion, ill-substantiated though it may be on its face.
Heydon JA also referred to R v Turner [1975] QB 834 at 840 [69] in which Lawton LJ said:
Before a court can assess the value of an opinion it must know the facts upon which it is based. If the expert has been misinformed about the facts or has taken irrelevant facts into consideration or has omitted to consider relevant ones, the opinion is likely to be valueless. In our judgement, counsel calling an expert should in examination in chief ask his witness to state the facts upon which his opinion is based. It is wrong to leave the other side to elicit the facts by cross‑examination.
It is therefore no answer to inadequacies in an expert report to hand the witness over for cross-examination. It is not for the opposing party, in this case the State, to cross-examine an expert opinion into admissibility. Given that inadequacies in an expert report will very often amount to a lack of disclosure, there is considerable unfairness in an expectation that, if the opposing party is dissatisfied with the report, it can explore the areas in which it says the report is unsatisfactory. (I note here that the defence in this case made the witness available out of a sense of uncertainty as to whether he was required and, according to the State's own submissions, an earlier indication had been given by the State that it did wish the witness to be available. Its position later changed.)
The State's position in declining to cross-examine the witness in the directions hearing was properly taken. The sufficiency of the factual underpinning of Professor Skerritt's opinion stands or falls on what is contained in his two reports.
Little information is contained in either of Professor Skerritt's reports as to the factual basis of the events of the night of the alleged offence upon which he expressed his opinion. It is obviously unlikely that Professor Skerritt would be in a position to prove any underlying facts about the alleged offence himself, except facts deriving from his opinion about the Accused's underlying psychiatric/psychological makeup generally.
As to the incident that night, the professor's opinion would normally be expected to be based upon an assumed factual scenario. Any facts which the professor took into account about the alleged offence can only have come from the Accused in his discussions with the professor, or by way of instructions from the defence, or from the prosecution brief. The letter from the defence to Professor Skerritt seeking his opinion posited no assumed factual scenario as the basis for his opinion, but simply enclosed the prosecution brief.
Professor Skerritt's first report contains no discrete section dealing with the history taken from the Accused about the events of the night. He was given the prosecution brief but, in his first report, Professor Skerritt stated:
I have been given a large folder of witness statements which are not necessarily relevant to the particular task given to me. One could conclude that there was a considerable altercation in and around the premises in Calista on 1^st October 2016. The party in progress at the time was for members of the motorcycle gang of which Mr Rassmussen was a member at the time although he has subsequently left it.
It is entirely unclear from the passage quoted above whether Professor Skerritt placed any reliance upon anything contained within the prosecution brief, including the Accused's version of events given to the police. The passage implies that little or nothing was drawn from the brief.
Even if it was, that method of summing up factual matters underpinning a report by way of a generalised reference to a volume of materials was regarded as inadequate by the Victorian Court of Criminal Appeal in the case of J (1994) 75 A Crim R 522. In that case, the prosecution called a psychiatrist who was also a psychologist to speak to the accommodation behaviour of a complainant in a sexual case in order to rebut defence suggestions that a victim of sexual abuse would not remain willingly in the family home and send birthday cards and the like. The doctor read much but not all of the transcript of the complainant's evidence and read witness statements on the brief which were not before the jury, and gave his evidence based on that broad factual basis without stating what facts he had assumed. Brooking J at [524], with whom Southwell and McDonald JJ concurred, criticised the method as failing to observe a long established rule:
In the second place, a witness who has neither heard the evidence nor read the transcript of it may have recounted to him by counsel while he is in the witness box certain facts, he being asked to assume that those facts are correct (those facts being of course drawn from the evidence), or, alternatively, he may be informed that a witness has given evidence of certain facts, which counsel thereupon relates to him, and asked to assume the correctness of those facts. Whatever method is adopted, the important thing is to make it clear precisely what evidence, assumed to be correct, or precisely what supposed facts, assumed to be established, are being placed before the witness for the purpose of his expressing an opinion. An expert witness must identify the facts assumed as the basis of the opinion. The rule is an old one, recognised at a time when the modern law of evidence was starting to emerge.
The inherent difficulty if a more generalised approach is taken is that, firstly, what is contained in the witness statements may not be how the evidence emerges at trial and what is contained in an accused's interview with police may or may not be consistent with any evidence the Accused may choose to give at trial. Further, the jury is the finder of the facts and may accept some parts of a witness's evidence, including statements made by an accused during an interview, and not others. Any assumed set of facts which simply consists of a broad reference to the prosecution brief does not enable the finder of fact to be able to assess what weight can be put on the opinion, because it cannot be determined whether facts that were critical to the opinion have failed to be established, or whether facts contrary to the underlying factual basis of the opinion have been proved which undermine the opinion.

In any event, the prosecution brief does not objectively support any conclusion that the party in progress was for members of the motorcycle gang of which the Accused was then a member. There is no suggestion in the brief, including the Accused's interview, that anyone at the party, other than the Accused who was wearing gang colours or clothing bearing a gang insignia, was a member of that gang. There is evidence by way of the Accused's interview that the former co‑accused Mr Lehman, called to the scene by the Accused, was also wearing clothing with gang initials. Indeed it is the State's case that one of the reasons why the complainant acted the way he did was because of his awareness that the Accused was a member of a gang.
Later in Professor Skerritt's first report, at the crucial point of considering the evidence for the Accused having entered into a dissociative state, Professor Skerritt stated:
In the case of Mr Rasmussen we have a fearful situation threatening violence in the presence of members of a 'bike gang', his mounting anxiety and switching off so that he did not remember anything until the crisis had passed.
When considering the critical question of whether this state of dissociation was prone to recur, Professor Skerritt stated:
… he was mostly in a state of psychological trauma which would produce a state of fear in a normal person but in his case went further than that and provoked symptoms of a pre-existing illness.
The state of fear that would arise in a normal person was the fear of being in a threatening violent situation in the presence of 'bikies' - but the professor was silent on a factual scenario where the person is himself associated with the 'bikies'.
And finally, a little later Professor Skerritt remarked of the Accused: 'He has left the "bikie" organisation which provoked the anxiety at least on this occasion'. That description either perpetuates a misunderstanding that the complainant and his companions were members of the bikie group, or suggests that the Accused suggested to Professor Skerritt that Mr Lehman's involvement - which the Accused brought about by calling Lehman to the scene - was the source of his anxiety. Without the history taken from the Accused it is impossible to known what scenario the professor was addressing.
Professor Skerritt's report did not identify the source of his assumption that the Accused suffered mounting anxiety and switched off - as to whether that came from the Accused directly, or was Professor Skerritt's interpretation of what the Accused said to police, or was a mere assumption based upon neither source. There is nothing in Professor Skerritt's report which links his opinion to the Accused's account in his interview with police. One might have expected the police interview to be expressly mentioned in the reports as having been viewed and identified as the factual source underpinning the opinions expressed, if it was.
Nor is there any description of what is said to have been the dissociative state, beyond the bare assertion that the Accused 'switched off'.
To make matters more complicated, Professor Skerritt also stated:
At the commencement of the consultation he launched into a number of matters which I had to point out were more of a legal nature. These included whether his defence should be in the nature of automatism, whether he was acting in self defence or whether indeed he actually committed the assault, which he was inclined to deny on the basis of enquiries that he had made. What was consistent throughout was that there was a gap in his memory which included the period of the alleged assault.
The consistent gap in memory said to have 'included' the period of the alleged assault impliedly extends to a period of time beyond the assault. In the Accused's interview, that gap (at its highest) was described as the brief period between the Accused grabbing the pole, which he remembered doing, and the complainant being on the ground. The outer limits of that gap in memory that Professor Skerritt took into account in reaching his opinion and how complete the lack of memory is said to be was not described by him. Nor were any of the memories leading up to the gap in memory. Without that description, it is impossible for the prosecution to assess whether the Accused provided Professor Skerritt with an account consistent with his account to the police, or not, and whether the account given was internally consistent, or not.
Without the professor having followed the usual course of detailing the history given by the subject by way of quotations or paraphrasing what he said, it is impossible to determine what version of events Professor Skerritt based his opinion on, if any, and whether or not his opinion that the Accused was in a dissociative state was based upon a positive account described to him by the Accused, or upon the Accused's lack of memory for an unspecified period of time, or upon the Accused's own announcement that he 'switched off' coupled with an interpretation of that claim in favour of disassociation.
It is not necessary that there be a formal section in the report entitled 'history' or 'discussion of alleged events' or the like, although it is usual to encounter such sections in expert reports, so long as the facts taken into account appear in the report somewhere but, without details of what factual scenario the professor based his opinion on, the fact finder has no way of knowing whether the underlying facts upon which the opinion depends are ultimately proven and, without such proof, the opinion has no foundation and is inadmissible.
That is not answered by having the Accused testify at trial and supply the facts he gave Professor Skerritt for the purposes of his opinion as, firstly, the State has a right to advance disclosure of the basis of the opinion and, second, such evidence will still beg the question as to just what it was that grounded the opinion given in January 2020.
On 19 February 2020, the State wrote a six-page letter to the Accused's lawyers, raising specific concerns about various aspects of the first report, concluding with a detailed request for further information from the defence and the professor, as follows:
Having regard to the above, if Defence wish to rely upon Dr Skerritt's report, the State request disclosure of the following material so that the State may properly assess the opinion expressed by Dr Skerritt, and may properly instruct its own expert in relation to the issue of automatism:
(a)Copies of the letters/request for the report sent by your office including any attachments and enclosures, and any records of telephone attendances or conversations had with Dr Skerritt about the preparation of the report;
(b)Copies of documentation relating to Dr Skerritt's qualifications and experience specific to the issue of automatism, including details of any practical experience and any knowledge gained externally from books, articles, papers and statistics relied upon to form his opinion;
(c)Copies of any notes made by Dr Skerritt during his interview [sic: with] the accused on 15 January 2020;
(d)Copies of any reports, notes, records, or materials relied upon by Dr Skerritt in formulating his report;
(e)An addendum report addressing the deficiencies identified in the current report and outlined above, including details as to [sic: the] factual foundation for the opinions expressed arising from Dr Skerritt's understanding of:
i.The factual circumstances in which the accused's purported malfunction of the mind occurred on this occasion (including how and when Dr Skerritt was made aware of this);
ii.The factual circumstances in which the accused's purported malfunction of the mind occurred on previous occasions (including how and when Dr Skerritt was made aware of this);
iii.The factual circumstances of the various incidents of childhood trauma suffered by the accused (including how and when Dr Skerritt was made aware of this);
iv.The factual circumstances of the various incidents of trauma suffered by the accused during his time in the army (including how and when Dr Skerritt was made aware of this);
v.The factual circumstances of any other incidents of trauma suffered by the accused relevant to the diagnoses of PTSD, ADD, Bi-Polar and Anxiety and Depression (including how and when Dr Skerritt was made aware of this);
vi.The details of any treatment engaged in by the accused which is relevant to Dr Skerritt's diagnoses of psychiatric illnesses, and his opinion in relation to the accused [sic: accused's] dissociation, including how such treatments and medication may affect the likelihood of the accused [sic: having] dissociated on this occasion and in the future; and
vii.Further explanation as to how the factors identified by Dr Skerritt in his report as affecting [sic] the proneness of the accused's disassociation recurring having regard to his assessment as to the underlying causes of the disassociation on this occasion and in the past.
Finally, in any event, in the event the State does engage their own expert, can you advise whether the accused would consent to being forensically examined by that expert for the purpose of the report?
While it is fair to say that the initial request from the Accused's lawyers to Professor Skerritt for a report provided little guidance to him, the letter from the State was detailed and clear. It is apparent from Professor Skerritt's second report that the letter from the State was forwarded to him for his consideration and that he did consider and respond to its contents in his second report.
In that second report, Professor Skerritt offered:
There is mention of the facts relating to the circumstances of the alleged offence. I was not really given the task of considering these but rather to look at the mental state of Mr Rasmussen at the time. I was quite satisfied it was a very ugly scene in which members of bikie gangs (related to me as such by Mr Rasmussen) were involved and that was enough for me to indicate the fearful nature of his reaction with respect to the possibility of disassociation and defence of automatism.
That clarification implies that Professor Skerritt did not base his opinion on any detailed account of the facts beyond an assertion, or his own erroneous understanding, that bikie gangs - multiple gangs now - were involved in some ugly scene - from which Professor Skerritt drew his own inferences as to a level of fear experienced by the Accused and a possible resulting dissociative state.
A little later, Professor Skerritt continued:
To put it more simply we have a situation of mounting tension in a fearful circumstance allegedly resulting in the person's brain 'switching off' as a defence against the fear.
And further:
… this was such a fearful situation and there was not a very good description of the nature of the anxiety experienced before the switching off process, that he [sic: his] could be considered to be a reaction that any normal person might have. When I review my casenotes I had great difficulty extracting a description of his feeling immediately before the supposed association [sic: dissociation. He described a great deal of fear and on pressing used the word 'panic' but I was not convinced that the word reflected his previous experience of so-called panic disorder.
Again, it is impossible to discern whether the conclusion that the Accused's brain 'switched off' was a quote from the Accused himself, or an interpretation of something the Accused said, in parenthesis because it was a colloquial expression, or an inference drawn from a claimed lack of memory for some unspecified period of time.
At best one can conclude that the Accused told Professor Skerritt that, at some stage prior to a memory loss of unspecified duration, he experienced fear and panic. There is no means for the fact-finder to know when, and in what sequence of events, that is said to have happened nor how extensive the memory loss is said to have been, nor whether the memory loss equates to the 'switching off' or, rather, was the factual basis for an inference of 'switching off'.
Professor Skerritt at least appears to hold the view that he can assess the Accused's mental state reasonably divorced from the factual account which may have preceded that mental state, which may be valid from a medical point of view based upon a simple acceptance of the patient's own description but, with respect to the professor, falls well short of what is required from an expert in a criminal trial. From the point of view of a fact-finder, it leaves the medical opinion divorced from the task of assessing what weight to place upon it. If expert opinion is not underpinned by proven facts, it is irrelevant and inadmissible.
The two reports between them do not sufficient identify the factual basis underlying the opinion offered as to the fact of the Accused having entered a dissociative state to render the opinion admissible.
There is also an issue in the various diagnoses contained in the first report. No underlying factual basis, except in the broadest implied terms, is provided in the first report for the diagnosis of ADHD. The second report contained the details that the diagnosis 'is based on a lifetime history going back to primary school' (which is not provided), an inability to read books and difficulty in concentrating. Nothing appears to turn, however, on the diagnoses of ADHD.
The factual basis provided in the first report for the diagnosis of bipolar disorder was also thin, but at least some facts were provided of the Accused having experienced abnormally high moods which made everyone laugh, thinking fast, talking fast and impulsive spending, but Professor Skerritt in any event discounted the relevance of the diagnosis of bipolar disorder in nature to his overall conclusion.
Although Professor Skerritt placed particular emphasis on the diagnosis of anxiety disorder, he did place some emphasis on his discussion as to whether the Accused meets the criteria for PTSD:
PTSD itself would not be considered relevant to that disassociation in the sense of the alleged offence although it is part of the criteria to do with the traumatic experiences. One might also comment that there is a great deal of overlap between the various categories designated in the manual. Anxiety and depressive symptoms however are very significant as precursors to dissociation in stressful circumstances.
The reference to PTSD being, or perhaps supplying, 'part of the criteria to do with traumatic experiences' does appear to relate directly to the overall conclusion that the Accused entered a dissociative state on the night in question. By way of providing the factual basis for the 'traumatic experiences' Professor Skerritt provides the following:
The traumas according to the Association have to involve 'exposure to actual or threatened death, serious injury' etc. The particular traumas in his experience were violence as a child and episodes of assault in the army.
That extremely generalised disclosure is inadequate for the purposes of the State, which is entitled to disclosure (including sufficient disclosure to enable it to consult an expert of its own for a second opinion) and, ultimately, the fact-finder.
The professor also attached to his first report the DSM 5 criteria for PTSD in an adult, with several of the criteria underlined, explaining that those underlined were described by the patient. The criteria underlined add nothing to the underlying factual basis, however, except for the first which adds merely that, in so far as the Accused was exposed to actual or threatened death or serious injury, that was by way of directly experiencing the event. That method of supplying an underlying factual basis is quite insufficient for the purposes of the State, which is entitled to disclosure, and the fact‑finder.
It is also of note that one of the criteria for PTSD which was not underlined appears in group B as follows:
Dissociative reactions (eg flashbacks) in which the individual feels or acts as if the traumatic event(s) were recurring. (Such reactions may occur on a continuum with the most extreme expression being a complete loss of awareness of present surroundings).
Professor Skerritt referred to the criteria in group B involving such matters as intrusive memories or flashbacks, commenting 'these were not prominent although he did mention sleeping with a hammer as a reaction to his experience in the army' - which experience was not described.
In his second report, addressing the complaint from the prosecution as to the failure of the first report to identify the underlying facts supporting the diagnoses, Professor Skerritt offered:
The 'factual basis' of my opinions were from my own clinical history with one exception. The diagnosis of Post-traumatic Stress Disorder was an invention of the American Psychiatric Association in 1980 and I customarily provide the set of criteria from my clinical examination of the patient which I have done in this case. The diagnoses of Attention Deficit Disorder, anxiety and depression preceded the American Psychiatric Association's definitions by decades and millennia respectively and I sought the clinical findings with the patient. These diagnoses with the exception of anxiety were not of particular importance in understanding the alleged offence.
He appears to be saying that he took his own clinical history from the Accused. It is not clear just what relevant distinction is being drawn in relation to the DSM 5 criteria for adult PTSD but, in any event, Professor Skerritt appears to have missed the point; the failure to provide the underlying factual basis for the diagnoses is not answered by, in effect, assuring the reader that there was one (if that is what the professor meant). The second report did not provide any history taken from the Accused in relation to the PTSD.
Turning now to the diagnosis of depression and anxiety, Professor Skerritt commented that there was overlap between some of the criteria for adult PTSD in DSM 5 and anxiety and depression. Those overlapping criteria, I infer from his discussion, are those underlined in groups C, D and E: avoidance of or efforts to avoid distressing memories, thoughts or feelings or external reminders of the traumatic event, a persistent negative emotional state with diminished interest in activities, sleep disturbance, irritability, angry outbursts, reckless behaviour, hypervigilance and exaggerated startle response and difficulty concentrating.
There is some broad implied underlying factual basis in the fact of those symptoms have been underlined, in that one can conclude that the Accused told the professor he had experienced such things at some stage in his life, but not sufficient for the purpose of informing a fact‑finder (and the prosecution which is entitled to disclosure) of the history given by the Accused. Professor Skerritt does refer to the Accused having considered suicide but having been deflected by thoughts of his sons, the future seeming hopeless, and having sleep disturbance which was helped somewhat by medication, but with no details as to when any of these symptoms were experienced and in what context.
Cryptically, the professor concluded 'I believe this group of symptoms were put in the category of major depressive disorder' suggesting reliance on the opinion of another, yet in his second report the professor stated 'My opinions and the basis in my clinical findings were entirely my own [sic: and in] no way dependent on those of my colleagues'.
Some further history taken from the Accused as to symptoms of anxiety was given in the first report:
The illness of anxiety, involving a dysregulation of the normal reaction of fear, is associated with two groups of symptoms. The first is of circular, repetitive worries which are very prominent in the case of Mr Rassmussen. He told me they had been treated for years but that the lamotrigine, perhaps contrary to expectation, had been particularly helpful. The other area of symptoms of anxiety consists of a variety of physical symptoms which at the worst occurs in attacks referred to as panic attacks. He described these as rapid heartbeat and breathing, drained of energy, nausea, sweating and shaking. These will occur in situations such as arguments, court appearances, new jobs and which will also keep him awake for days with the worries. I think that his anxiety disorder is thus not part of the so-called adjustment disorder but the more significant panic disorder (favoured by the American Psychiatric Association where panic attacks are most prominent) and generalised anxiety disorder (when the circular worrying thoughts are most prominent. They usually occur together.

So one can assume that the Accused gave a history of both circular repetitive worries over years and symptoms of anxiety in anxiety‑producing situations, which at their most severe amounted to panic attacks, although no details were given as the frequency of the panic attacks, nor how long the Accused has been prone to them. The reference to 'new jobs' might suggest a situation of some duration, but there is no detail given about when such jobs were commenced, whether each new job brought on an attack, or whether the Accused usually experienced something less than a panic attack. Similarly, the reference to 'court appearances' with no accompanying detail is unhelpful, particularly given that the Accused has a six-page criminal record.
But the most glaring deficiency in the disclosure of the underlying factual basis was in the following paragraph which is the crux of the first report (emphasis added):
we have a fearful situation threatening violence in the presence of members of a 'bikie gang', his mounting anxiety and switching off so that he did not remember anything until the crisis had passed. There is a history that such occurrences have happened previously and he had a clear diagnosis of the anxiety disorders.
Again, in his consideration of whether the Accused has an illness which is prone to recur, Professor Skerritt stated (emphasis added):
the best way of predicting the future is to look to the past and the history suggested that there had been other episodes of anxiety with the defence of disassociation.
Nowhere in Professor Skerritt's first report was there given any history of the Accused having experienced some previous incident of 'switching off so that he did not remember anything until the crisis had passed'. In relation to the diagnosis of PTSD, a criterion of 'avoidance of or efforts to avoid distressing memories' was underlined, but with no detail given and no basis for the reader to infer that what had been reported was a history of complete absence of memory, as opposed to avoidance of distressing memories. Further, the criterion of dissociative reactions was not underlined.
A bald assertion of such past history falls well short of what is required in an expert report provided for the purposes of a defence to a criminal charge. And disclosure of any history of previous dissociation is critical in a criminal trial in which a distinction must be drawn between unsoundness of mind and non-insane automatism.
Professor Skerritt's second report gave no factual foundation for any assertion of a past history of having switched off and having been left with no memory. It implied the opposite:
I believe I described the two areas of symptoms of anxiety, circular repetitive thoughts and panic attacks both of which were described to me by Mr Rasmussen.
Nothing was added. The passage suggests that Professor Skerritt felt that his description of those symptoms was sufficient and covered the factual basis underpinning the diagnosis of anxiety disorder. If there was more - if there was the presumably quite striking feature of previous instances of dissociation and complete memory loss - one might expect it to have warranted some mention at that point.
And yet, when addressing the issue of whether dissociation in the Accused was likely to recur, Professor Skerritt commenced (emphasis added):
If the panic that was described in his life before was provoked in the circumstances, the legal question is whether this constitutes 'insane' automatism.
It is impossible to know what to draw from this passage. There is an ambiguity as to whether the professor is in fact questioning whether previous panic was provoked, or whether panic such as has occurred on previous occasions was provoked on the occasion the subject of the charge - the former is more likely than the latter, but it is entirely unclear. On the basis that it is the former, it suggests that the earlier references to past 'such occurrences' and 'other episodes of anxiety with the defence of dissociation' were in fact references to panic attacks, which have been described by the Accused and did not include a description of disassociation or lack of memory (unless they did, which has not been described). This passage also suggests that the history taken by Professor Skerritt did not enable him to express an opinion as to whether past occurrences were provoked or not, but merely posed a question.
So either there was no factual basis underpinning the above reference to past history of 'such occurrences', or there is a history of past instances of dissociation which is important and not disclosed in either report.
The deficiencies throughout both reports in identifying the factual circumstances relied upon in arriving at the various conclusions discussed above are significant.
The specific factual matters which ought to have been disclosed were set out with clarity in the State's letter of 19 February 2020. The failure to adequately identify the assumed factual basis underlying the opinion of Professor Skerritt is very substantial - sufficiently substantial to go beyond mere weight. It renders the opinion inadmissible.

Does Professor Skerritt reveal his reasoning process sufficient for it to be tested and evaluated by the jury?

Professor Skerritt's ultimate opinion that the Accused was in a dissociated state was either based upon the Accused having a history of anxiety disorder including a history of previous instances of having experienced mounting anxiety and switching off until the crisis had passed - for which no underlying facts were provided - or it must have been based on a history of past anxiety symptoms alone coupled with the bald assertion that the Accused switched off and cannot remember anything. Professor Skerritt indicated an association between anxiety disorder and dissociation:
In the midst of these diagnostic combinations it is the anxiety disorders that are typically associated with the defence of dissociation where the brain copes with the overwhelming fear by switching off the stream of consciousness and in such circumstances automatic behaviour, that is not under the exertion of the will can occur.
Having then married (a) the 'fearful situation threatening violence in the presence of members of a 'bikie gang' - a flawed factual scenario in which what the Accused actually told the professor is not quoted - to (b) the Accused having 'switched off' such that he had no memory - presumably based on something the Accused told him of which no details were given - together with (c) the Accused's 'history of anxiety disorder' - together with (d) a 'history that such occurrences have happened previously' - for which there was no basis given, Professor Skerritt concluded there is 'sufficient evidence that he was in a dissociative state, or automatism in legal terms'.
Given the lack of factual underpinning for each of (a), (b), (d) and to a lesser extent (c), it is impossible to discern, firstly, whether in Professor Skerritt's opinion, a lack of memory equates to a dissociative state, or whether something more in some history given to him by the Accused influenced his opinion. I have already discussed the lack of information provided as to whether 'switching off' causes lack of memory or is merely evidenced by lack of memory, and whether and how dissociation can be distinguished from mere lack of memory, and the possible causes of each.
It is also impossible to discern whether 'switched off' was the Accused's expression or Professor Skerritt's, and whether or not some description was given by the Accused of that state or whether it was a claim of lack of memory that was decisive.
It is impossible to discern whether the professor's conclusion depended upon there having been some history (undisclosed) of such occurrences previously, or whether his opinion would remain the same if there was no factual basis for that assertion.
I have already discussed the scant explanation given in both reports as to the concept of dissociation generally, as occurring:
where the brain copes with the overwhelming fear by switching off the stream of consciousness and in such circumstances automatic behaviour, that is not under the exertion of the will can occur.
No further details were provided as to what it means to switch off the stream of consciousness - as opposed to lapsing into unconsciousness. And no explanation was given as to what sort of automatic behaviour man is capable of, what processes of thought are engaged in automatic behaviour, and what sort of decision making capacity and level of understanding is and is not retained in automatic behaviour.
In the above respects, Professor Skerritt's reasoning process has not been revealed sufficiently to enable the opinion to be assessed by the State, by another expert and by the fact-finder.
Moving on now to Professor Skerritt's consideration of whether the automatism was 'sane' or 'insane', and leaving to one side the commentary on the state of the law (quoted in full earlier), his conclusion was:
… he was mostly in a state of psychological trauma which would produce a state of fear in a normal person but in his case went further than that and provoked symptoms of a pre-existing illness.
I understand that passage to mean that Professor Skerritt accepted that the mental malfunction caused by the psychological trauma was not that of an otherwise sound mind. After all, what he attributed to the normal person in such a situation was a likely 'state of fear'. What he concluded occurred to the Accused was a 'state of dissociation'. If the defence contends that this passage in fact conveys that the Accused suffered a transient mental malfunction of his otherwise sound mind caused by trauma, then the reasoning process is not clear.
Professor Skerritt then turned to the issue of whether the malfunction is likely to recur:
That leaves the question of the proneness of such disassociation to recur … The best way of predicting the future is to look at the past and the history suggested that there had been other episodes of anxiety with the defence of disassociation. I might agree with my colleague, however, that it is not likely to recur under the circumstances.
He has left the 'bikie' organisation which provoked the anxiety at least on this occasion. A positive feature of his personality is his ability to work and he is employed in a regular FIFO job indicating a general settling of his mental state.
He has successfully embarked on several trade qualifications. He is under regular psychiatric treatment which has produced some benefit by his own account from the anxiety with the approach of two different medications …
With all of these factors I think that his proneness to recur can be regarded as minimal.
The prosecution complains that Professor Skerritt has failed to reveal his process of reasoning in the passage above. His process of reasoning has been substantially revealed. It is to the effect that, on the information the professor has, the Accused is unlikely to again find himself in a 'fearful situation threatening violence in the presence of members of a 'bikie gang' - and so there is a minimal chance that he will again enter a dissociative state.
Of course, it rather flies in the face of Professor Skerritt's references to past instances in which the Accused apparently has entered a dissociative state, as to which no history is provided. There is no way of knowing whether any past instances, if there have been past instances, were fearful situations threatening violence in the presence of members of a 'bikie gang', which goes back to the failure to disclose the underlying factual assumptions supporting the opinion.
And the process of reasoning does not capture what is meant by the expression 'not likely to recur' as it is used in the authorities - which captures a transient mental malfunction, not likely to recur, of an otherwise sound mind to psychological trauma, not whether or not the factual scenario giving rise to the psychological trauma is likely to recur. Be that as it may, I consider Professor Skerritt's process of reasoning is substantially revealed.
With respect to the professor, however, his reasoning process in his second report is opaque:
This is known as disassociation. The question then is whether this is related to a mental illness or might have occurred as a normal defence to an abnormal circumstance.
If the panic that was described in his life before was provoked in the circumstances, the legal question is whether this constitutes 'insane' automatism. My suggestion was that this was such a fearful situation and there was not a very good description of the nature of the anxiety experienced before the switching off process, that he [sic: his] could be considered to be a reaction that any normal person might have. When I review my casenotes I had great difficulty extracting a description of his feeling immediately before the supposed association [sic: dissociation]. He described a great deal of fear and on pressing used the word 'panic' but I was not convinced that the word reflected his previous experience of so-called panic disorder.
I have already discussed the real difficulties in discerning precisely what opinion was being expressed in this passage.
While, in his first report, Professor Skerritt included the history of past 'such occurrences' as part of the evidence that the Accused entered a dissociative state on the night of the alleged offence, in his second report he both contrasted the Accused's past experiences with the current incident, notwithstanding the Accused's apparent use of the word 'panic', and also introduced the possibility that in each previous incident - about which the reader has been told nothing - the panic may have been 'provoked'.
Precisely what was meant by the word 'provoked' in this context is not clear and suggests that Professor Skerritt was not there discussing panic attacks caused by new jobs and court appearances, but one cannot be sure.
The introduction of the word 'provoked' also suggests that Professor Skerritt was querying - although not expressing an opinion - whether each of those past occasions may have been provoked, and hence have constituted a temporary malfunction of an otherwise sound mind to psychological trauma - if that is what is meant by 'provoked' - therefore perhaps suggesting to Professor Skerritt that the recurrence in the past did not in fact suggest a likelihood of recurrence. If the suggestion is that, on previous occasions where disassociation occurred, the Accused was then experiencing the reaction of a sound mind to a psychological trauma and has simply been unfortunate enough to have had this occur multiple times in his life, then perhaps Professor Skerritt was querying whether the Accused's panic disorder was unconnected to the claimed dissociative state.
Of course, having been provided with no information about those said past occurrences, the fact-finder has no ability to even consider the question posed by the professor. And the fact that Professor Skerritt posed the question - if the panic that was described in his life before was provoked in the circumstances - suggests that he had no, or no sufficient, history from the Accused that would enable him to express any opinion on that question.
The shift in position between the two reports does place the prosecution - and ultimately the fact-finder - in the position of being unable to discern just what opinion was being expressed by the second report and by the two reports in their totality. If, contrary to my reading, these passages do not represent a shift in position between the two reports, then the opinion being expressed is truly opaque. If the opinion being expressed cannot be pinned down, then it cannot be of assistance to the fact-finder and is irrelevant.
Added to the lack of disclosure of the factual basis, to the extent to which there was a factual basis, underpinning the report, the prosecution is placed in the entirely unsatisfactory positon of not knowing what opinion it needs to meet. The failure to reveal the process of reasoning was very substantial, going beyond mere weight and rendering the opinion inadmissible on this ground as well.

Is Professor Skerritt sufficiently qualified to express his opinions?

The first of the requirements for the admissibility of expert evidence is that the witness must be an expert (Heydon JA at [85] in Makita):
In short, if evidence tendered as expert opinion evidence is to be admissible, it must be agreed or demonstrated that there is a field of 'specialised knowledge'; there must be an identified aspect of that field in which the witness demonstrates that by reason of specified training, study or experience, the witness has become an expert.
The authors of Expert Evidence: Law & Practice (5^th ed, 2020) 1‑027 argue the test of expertise (in the United Kingdom) should be seen as a matter of weight rather than admissibility:
First, it is obvious from the cases that the test of expertise is not one of great precision, especially because it can depend upon the nature of the matters which require proof and assumes a wide discretion in the court which considers it. Secondly, it appears to be recognised that the most effective way of assessing expertise is, rather than conducting a difficult exercise based almost entirely upon the limited evidence available as to qualification, experience and skill at the admissibility stage, to hear the witness's substantive evidence and use this as the basis upon which to judge not only the quality of their evidence, but also their competence to give it. Thirdly, and following directly from this second point, the degree of expertise revealed by the witness in their evidence is inevitably an important part of the process of attributing weight to the evidence in order to decide the issues. It would indeed be an exercise of some artificiality to attempt to effect complete separation between the question of expertise and that of the persuasiveness of the evidence given by the witness.
The authors contrast an Australian decision of McNeil v Commissioner of Taxation [2003] FCA 958, however, in which a qualified chartered accountant with extensive training and experience in general tax, valuation and audit principles was considered to lack the requisite expertise in sophisticated areas of taxation such as to comment on the benefit to be derived from the realisation of sell-back rights in a particular transaction. The witness's evidence had already been ruled inadmissible, however, on the basis that it largely did no more than summarise the documentation making up the share buy-back scheme, which was not in issue, and was therefore unable to rationally affect the assessment of the probability of the existence of a fact in issue in the case. But the case does support the proposition that merely being an expert in a broad field, but not having that extra expertise in the matter in issue, may not be sufficient. Much will depend upon the case and what expertise will actually be of assistance to the fact-finder.
Official academic qualifications are not necessarily determinative of the question of expertise. In SWD v The State of Western Australia [2017] WASCA 39, an appeal against conviction on six counts of sexual penetration of a lineal relative under the age of 16, the expertise of a general practitioner was considered sufficient to give evidence of old and significant injuries to the child's genitals. While not a gynaecologist, the doctor was a qualified medical practitioner who had practiced in the country town for 17 years as a general practitioner, had an interest in gynaecology, had practical experience in gynaecological issues in her practice and had also previously practised in the Pilbara for five years undertaking the forensic examinations of children who were alleged victims of sexual abuse. The court held that the relevant field of specialised knowledge from which an expert witness would be drawn was the medical field of gynaecology:
101… Before the trial court could receive Dr Spencer's opinion evidence on questions of gynaecology, the trial judge would have to be satisfied that she had acquired, by study or experience, sufficient knowledge of the subject to render her opinion of value in resolving the issues before the court.
102There is no doubt that Dr Spencer's evidence was properly admitted as expert opinion evidence in the appellant's trial. Dr Spencer was a qualified medical practitioner. Although not a specialist gynaecologist, she had considerable experience in gynaecology, including in the examination of suspected victims of child abuse in the Pilbara. Her opinion evidence was based on the observations which she made on the clinical examination of S, which she recounted. Dr Spencer had acquired, by study and experience, sufficient knowledge of gynaecology to render her opinion of value in resolving the issues before the court.

In essence, it is the defence position that the appropriate expert to speak to dissociation is a psychiatrist and, as Professor Skerritt is a psychiatrist, and one with a particular interest in dissociation, he is therefore sufficiently qualified to testify as per his reports.
It is uncontroversial that psychiatry is the appropriate field of specialised knowledge from which an appropriately qualified expert would be sourced and that the concept of dissociation is not within the general knowledge of the layman and that a jury would benefit from, and indeed require, expert assistance to understand such a concept.
It is also uncontroversial that Professor Skerritt is highly qualified in his field. His Curriculum Vitae, attached to his second report, speaks to significant and current experience as a psychiatrist. He currently holds the positions of Clinical Professor at the School of Psychiatry and Clinical Neuroscience at the University of Western Australia and Emeritus Consultant Psychiatrist at Royal Perth Hospital, and works as a psychiatrist both in private practice and at Joondalup Health Campus. He worked as senior registrar in psychiatry at Royal Perth Hospital in 1973, as a psychiatrist in 1975 and by 1985 was the Chairman and Head of the Department of Psychiatry at that hospital. From 1997 to 2001 he was the Clinical Head at Joondalup Community Mental Health and from 1998 to 2007 was the Director of Mental Health Services at Joondalup Health Campus. He has multiple fellowships, multiple professional associations and honorary appointments, has had a long association with the University of Western Australia, including years of lecturing, and currently holds the position of Clinical Professor referred to above. He is on various editorial boards and is published and has presented at national and international meetings.
The State's position, however, is that the reports from Professor Skerritt do not contain sufficient information for this court to assess whether, by reason of specified training, study or experience, the witness has become an expert in dissociation particularly and that such expertise is required.
Freckleton & Selby, Expert Evidence (Thomson Lawbook Co, 2018, Vol 3) at [50.800] describes the distinction between sane and insane automatism as 'particularly difficult' and automatism said to have arisen through a 'psychological blow' as 'a particularly controversial area of automatism'. The evidence is proposed to be led before a jury in a criminal trial of a serious charge.
The onus of qualifying the witness as an expert falls upon the party seeking to call the witness. The case of J referred to earlier supports the view that academic qualifications and broad experience in the field do not, without more, establish expertise. The witness in that case was both a psychiatrist and psychologist and well experienced in his field, but the evidence given failed to establish sufficient expertise on his part in the syndrome (itself inadequately identified) being relied upon to explain the complainant's accommodation behaviour. Brooking J, with whom Southwell and McDonald JJ concurred, expressed a degree of frustration with the manner in which the evidence had been led (532) ‑ (533):
The failure of the witness to refer, even in the most general of terms, to papers or symposia or anything of that kind on the subject of sexually abused children as opposed to battered women does suggest that he was not aware of any, although I must say that I should surmise that specialist literature on the subject of patterns of behaviour and responses of sexually abused children was available. There was in this case no mention of the suggested 'child sexual abuse accommodation syndrome', evidence about which has been given in a number of cases … The failure to use a label is of no importance; what is important is that there was no real attempt in the present case to show that psychologists and psychiatrists recognised that children and young person sexually abused by persons in a position of trust usually reacted to the stress in certain stated ways.
In addition, once the evidence of Dr Bartholomew on the voir dire and the trial is scrutinised, it should be said that even as regards the battered woman syndrome he did not sufficiently make it appear that the syndrome was a recognised psychological condition or that he was qualified to speak about it… I think it likely that both these defects were curable, but we can only take the evidence as we find it in this case. In case these remarks of mine are misunderstood and it is suggested that I am either denying the existence of the battered woman syndrome or not giving credit to Dr Bartholomew's undoubted expertise, let me repeat that my remarks here are based solely on the inadequacy of the evidence actually lead in this case on the voir dire and the inadequacy of the evidence actually lead in this case on the trial.
The proposition advanced by the defence that, in effect, any psychiatrist is an expert in dissociation is put by way of bald assertion. Nothing in Professor Skerritt's report speaks to that proposition. Psychiatry is a very large field of expertise. The fact that Professor Skerritt has provided an opinion in relation to dissociation does not of itself demonstrate that, by reason of specified training, study or experience, he has become an expert in dissociation.
The topics covered in the list of publications authored or co‑authored by Professor Skerritt are broad, revealing an interest in pain management and psychiatric issues such as depression as the sequelae of physical injury, including workplace related injury. Professor Skerritt was on notice from the State's letter of 19 February 2020 that the State was seeking any details he could provide indicating expertise specific to the issue of automatism. None of the titles of the articles published suggest any relevance to dissociation.
In his second report, Professor Skerritt offered the following:
I have been attending the various courts civil and criminal in Western Australia since about 1974 shortly after I commenced practice in Western Australia. I have always had a particular interest in the defence of automatism and have presented it to courts on a number of occasions. The case of Falconer in 1990 referred to by the DPP perhaps kindled my interest in the subject. I was not involved in the case in person but acquainted with some of the participants. I have always presented my opinions to the legal system from the basis of a practising psychiatrist. I am not aware of a body of papers, books or statistics that might have contributed more to my knowledge than consideration of the cases presented to me.
No further information was provided as to how many cases amounts to 'a number of occasions', nor which cases they were, nor which courts he was called to testify before, nor whether the evidence 'presented' to the courts was by way of testimony or written report and whether the evidence was meaningfully challenged but accepted by the court.
The passage above does imply that the professor has some level of clinical experience in dealing with patients in which some consideration of automatism has been relevant. But no information was provided as to how many cases Professor Skerritt has encountered in a clinical context involving dissociation, whether he was called to testify or not.
The defence provided some further disclosure to the State by way of email dated 3 June 2020:
He has given evidence previously in respect of automatism in criminal trials. To the best of his memory those trials have been conducted before Magistrate's Court jurisdiction. He recalled one, unnamed trial in Bunbury/Busselton Magistrate's Court which was successful for the defence. He did not provide any further information in respect of this background. He does not recall giving evidence before Judge and jury specifically in respect of automatism.
Such minimal information does not enable the State to review and assess any evidence Professor Skerritt has ever given on this topic.
The reference to Falconer does not advance the issue, being merely a case which interested him, but in which he had no involvement.
The professor also appears to expressly limit his expertise to his personal clinical experience, rather than by means of keeping abreast of current literature and studies, although his statement in that regard is ambiguous. But there is no information before the court to indicate that his knowledge is kept up-to-date by current studies and literature - or alternatively any indication that current literature and studies are limited.
And finally, the description given in his reports of dissociation, its causes and features was very scant. Professor Skerritt indicated an association between anxiety disorder and dissociation:
… it is the anxiety disorders that are typically associated with the defence of dissociation where the brain copes with the overwhelming fear by switching off the stream of consciousness and in such circumstances automatic behaviour, that is not under the exertion of the will can occur.
In his second report he described dissociation as 'the person's brain "switching off" as a defence against the fear'.
No explanation was given of what was meant by 'it is the anxiety disorders that are typically associated with the defence of dissociation'. No further details were provided as to what it means to switch off the stream of consciousness - as opposed to lapsing into unconsciousness. After all, on no factual scenario presented in the case did the Accused lapse into a physically passive state. And no explanation was given as to what sort of automatic behaviour man is capable of, what processes of thought are engaged in automatic behaviour, and what sort of decision making capacity and level of understanding is and is not retained in automatic behaviour.
No explanation was given as to whether 'switching off' causes lack of memory and, if so, how - whether it causes inability to access memories or actually prevents memories from being laid down - or whether, rather, dissociation is merely evidenced by lack of memory.
Although there is a suggestion in the report that the Accused had previously entered a dissociative state on other occasions, there was no discussion about whether that of itself amounts to some sort of dissociative disorder.
There is no information in either report that specifically addresses the issue of whether expertise is required over and above being a psychiatrist. There is no solid information put before the court upon which to assess whether other psychiatrists in the field specialise in this area of automatism and have very significant expertise over that of general psychiatry. Just as the defence relies upon assertion to satisfy me that a qualified psychiatrist has sufficient expertise, the State relies upon assertion to satisfy me that automatism is a complicated area and that expertise over and above being qualified as a psychiatrist needs to be demonstrated. Professor Skerritt has not identified the area of automatism as being outside his field of expertise. But the content of the two reports do not on their face reveal an obvious depth of knowledge and clinical experience in that area. Had there been more adequate disclosure of the reasoning process and the factual basis underpinning the opinion, that level of expertise may have become evident, but it is not evident on the materials currently before the court.
The evidence in this case falls short of the sort of evidence led in the case of the The State of Western Australia v Silich [2011] WASCA 135, an appeal against a conviction for two counts of wilful murder in which the defence case was that the jury could not be satisfied that the appellant had not been sleepwalking at the relevant time. A qualified psychiatrist was called on behalf of the State to testify on the subject of sleepwalking. One of the grounds of appeal challenged the admissibility of that evidence on the basis that the psychiatrist was insufficiently qualified as an expert, because he lacked appropriate qualifications or experience in sleep medicine or sleep science, was not qualified to conduct a sleep study and failed to demonstrate current knowledge of the relevant literature relating to sleep medicine or sleep science. Martin CJ at [73], with whom Buss JA and Hall J agreed, Buss JA also giving reasons on this ground, found that
the issues involved were those associated with parasomnia, somnambulism and dissociative mental states. While these may be aspects of a broader field loosely described as 'sleep science or sleep medicine', the evidence clearly established that they were also aspects of the field of psychiatry, in which Dr Varghese was qualified.
Apart from being qualified in the field of psychiatry generally, the doctor had specialised in the area of forensic psychiatry and given evidence in a number of criminal cases and
74.… in that capacity, he has experience of two previous criminal cases in which issues relating to sleepwalking arose. Outside the criminal area, Dr Varghese has experience of several dozen cases in which issues arose as to dissociative sleepwalking.
It was the doctor's evidence that the diagnosis of sleepwalking fell within the field of psychiatry and that, when such issues arose, psychiatrist would often liaise with respiratory physicians who were qualified to assess sleep apnoea and he had done so himself, explaining that the role of the respiratory physician was focused upon identification of the sleep disorder whereas the role of the psychiatrist was focused upon the psychiatric consequences of that disorder. It was conceded that he had never specialised in the field of sleep medicine or attended conferences focused upon sleep disorders because such conferences were mainly about the physiology of sleep, not his focus. The trial judge had ruled that he was qualified to express opinions within the limits of his expertise as a psychiatrist, namely as to the behavioural disorders associated with dissociative states, including somnambulism. The trial judge regarded the weight to be given to those opinions, having regard to the doctor's lack of specialisation in sleep disorder, was a question for the jury but did not render the evidence inadmissible. Martin CJ described that ruling as having been 'plainly correct'.
The evidence provided by the expert in the trial as to his relevant expertise somewhat exceeded the information provided by Professor Skerritt in this case as to his expertise.
None of these comments mean that Professor Skerritt does not in fact have expertise as to the concept of dissociation, but he does not demonstrably possess expertise in the area of automatism over and above that of simply being a psychiatrist. But he is a highly qualified psychiatrist and psychiatry is the relevant field of expertise in this case. Had the reports been otherwise adequate, the State would have been in a position to seek an expert opinion of its own, which I expect would have cast greater light on whether a qualified psychiatrist can be expected to possess sufficient depth of information and experience in the area of automatism to give evidence of sufficient expertise to be of value to the factfinder. But then, had the reports been otherwise adequate, and adequately disclosed the factual basis underpinning the opinion sought to be led and demonstrated the reasoning process which led to the opinion, the witness's expertise may have been more apparent from the sheer content of the discussion.
Decisions on the facts are for the jury, including issues of what weight should be attached to any expert opinion. Expertise, however, is also a threshold question in that only an expert may give opinion evidence to prove a fact.
Although I consider this to be a borderline decision, on account of the fact that Professor Skerritt is clearly a highly qualified psychiatrist and has claimed some particular interest and some experience in the area of dissociation, together with an acceptance that psychiatry is the field to which expertise in dissociation properly belongs, were the reports in all other respects adequate I would have been inclined to admit the evidence, leaving the question of the extent of the witness's expertise to go to the question of weight, rather than admissibility.
As it is, however, the question is somewhat academic, as the reports are not in all other respects adequate.

Relevance

Over and above the difficulties with the two reports identified above, the State objects to the evidence of Professor Skerritt on the grounds that it is irrelevant because it tends to establish neither a defence of non-insane automatism, nor a qualified defence of insanity.
Given the content of the letter from the accused's lawyers to Professor Skerritt seeking his opinion, it does not appear that it was his focus to address a qualified defence of insanity. The two reports do not expressly address the question of whether, at the time of doing the act, the Accused was in 'such a state of mental impairment as to deprive him of capacity to understand what he is doing, or of capacity to control his actions, or of capacity to know that he ought not to do the act', as is required by the language of s 27 Criminal Code.
The focus of the reports was upon automatism. The conclusions reached in the first report do not tend to support a defence of non‑insane automatism, because of Professor Skerritt's conclusion that:
he was mostly in a state of psychological trauma which would produce a state of fear in a normal person but in his case went further than that and provoked symptoms of a pre-existing illness.
That conclusion is inconsistent with the application of s 23A to the case. If automatism is the result of a defect or disease of the mind, s 27 Criminal Code provides the appropriate defence. The shift in stance between the first and second reports, however, discussed earlier, confuses the issue considerably:
If the panic that was described in his life before was provoked in the circumstances, the legal question is whether this constitutes 'insane' automatism. My suggestion was that this was such a fearful situation and there was not a very good description of the nature of the anxiety experienced before the switching off process, that he [sic: his] could be considered to be a reaction that any normal person might have. When I review my casenotes I had great difficulty extracting a description of his feeling immediately before the supposed association [sic: dissociation]. He described a great deal of fear and on pressing used the word 'panic' but I was not convinced that the word reflected his previous experience of so-called panic disorder.
It is very difficult to discern what opinion is being expressed in this passage, but it is at least possible that Professor Skerritt in his second report was opining that the dissociative state was not in fact a recurrence of a previous existing illness but was something new, contrary to his previous opinion. It is also possible that Professor Skerritt was querying the possibility, without expressing an opinion, that previous episodes of dissociation - if there were previous episodes of dissociation - were also not indicative of existing illness but, rather, each was the provoked response of a sound mind to trauma.
Of course, having been provided with no information about those said past occurrences, the fact-finder has no ability to even consider the question posed by the professor. And Professor Skerritt in fact expressed no opinion on the question posed by him, suggesting that the history taken by him was inadequate for that purpose.
If an opinion proffered by an expert suffers from an opacity of reasoning such that the opinion cannot really be identified, then it cannot be relevant. The point of expert opinion evidence is to offer the fact finder expert assistance on matters which are outside his common knowledge and experience. If the opinion cannot be identified, then it cannot be of assistance.

As the opinion expressed in both reports currently stands, it cannot be said that Professor Skerritt's opinion, underpinned by a factual basis which can be tested and proved, tends to prove that the accused entered a state of automatism which was a merely transient mental malfunction of his otherwise sound mind caused by trauma and that such malfunction is not likely to recur. The opinion of Professor Skerritt does not provide a proper basis for consideration of automatism for the purpose of determining whether the incriminating act was willed or voluntary: Falconer [29] (Mason CJ, Brennan and McHugh JJ).
Therefore the evidence is irrelevant and, it follows, inadmissible.

Conclusion

On the materials presently before the court, the opinion evidence of Professor Skerritt is inadmissible on the grounds that neither the factual basis underpinning the opinion, nor the process of reasoning leading to that opinion, has been adequately identified and, in any event, the opinion does not tend to establish a defence of non-insane automatism, or a qualified defence of insanity.

I certify that the preceding paragraph(s) comprise the reasons for decision of the District Court of Western Australia.
DD
Associate to Judge Sweeney
18 DECEMBER 2020