R v Somerville
[2025] SASC 39
•20 March 2025
SUPREME COURT OF SOUTH AUSTRALIA
(Criminal)
R v SOMERVILLE
Criminal Trial by Judge Alone
[2025] SASC 39
Reasons for Decision of the Honourable Justice McDonald
20 March 2025
CRIMINAL LAW - GENERAL MATTERS - CRIMINAL LIABILITY AND CAPACITY - DEFENCE MATTERS - INSANITY AND MENTAL IMPAIRMENT
CRIMINAL LAW - GENERAL MATTERS - CRIMINAL LIABILITY AND CAPACITY - DEFENCE MATTERS - INTOXICATION - INDUCING INSANITY OR MENTAL IMPAIRMENT
The defendant is charged with two counts of attempted murder, arising out of her conduct on 15 August 2022. The defendant has previously been diagnosed with a bipolar affective disorder and more recently has been diagnosed with Schizophrenia. The defendant has an extensive mental health history. At the time of the conduct, according to expert evidence, the defendant had enough methylamphetamine in her system to induce a range of physiological and behavioural effects as well as psychotic symptoms and aggressive and violent behaviour. The expert evidence also suggested that at the time of the conduct the defendant had enough cannabis in her system to place her at an elevated risk of experiencing psychotic effects when combined with her Schizophrenia.
On 13 February 2023, this Court ordered an investigation into the defendant’s mental competence under Part 8A of the Criminal Law Consolidation Act 1935 (SA) (‘the Act’). The defendant elected to proceed by trial by Judge alone. The defence conceded that the objective elements of the offences had been proved beyond reasonable doubt. The prosecution conceded that the defendant was mentally incompetent to commit the offences under s 269C(1) of the Act, however argued that the mental incompetence was substantially caused by self-induced intoxication as a result of methylamphetamine consumption.
Subject to the Part 8A investigation, three forensic psychiatrists and a pharmacologist completed written reports, and the Court heard evidence from two of the experts on the question as to whether the defendant’s mental incompetence at the time of the conduct was substantially caused by self-induced intoxication.
Held:
1. On the balance of probabilities, the defendant’s mental impairment at the time of the conduct giving rise to the offences was substantially caused by self-induced intoxication.
2. The criteria under s 269C(3) is satisfied. Despite the fact that the defendant’s conduct was substantially caused by self-induced intoxication, she is to be dealt with under Part 8A of the Act.
3. The defendant is not guilty of the offences of attempted murder by reason of mental incompetence pursuant to s 269G B(3)(a) of the Act.
4. The defendant is to be declared liable to supervision pursuant to s 269G B(3)(a) and under Division 4 Subdivision 2 of the Act.
Criminal Law Consolidation Act 1935 (SA) s 269C(1)(a), s 269C(1)(b), s 269C(1)(c), s 269C(2), s 269C(3), s 269D, s 269G B(3)(a), referred to.
Question of Law Reserved (No 1 of 2021) (2021) 140 SASR 135; R v Tripodi (2002) 136 A Crim R 514, applied.
R v SOMERVILLE
[2025] SASC 39Criminal: Trial by Judge Alone
McDONALD J.
Megan Jayne Somerville has been charged with two counts of attempted murder.
On 15 August 2022, Ms Somerville stabbed both of her sons multiple times with a knife, whilst driving her vehicle on the North-South Motorway. She then stopped on the overpass at Wingfield, removed one child from the vehicle, with the other exiting himself, and again stabbed them multiple times. Both children survived but were badly injured.
On 13 February 2023, I ordered an investigation into Ms Somerville’s mental competence under Part 8A of the Criminal Law Consolidation Act 1935 (SA) (‘the Act’).
Ms Somerville elected for trial by judge alone. This application was granted on 26 February 2024. On that same date, counsel for Ms Somerville confirmed that it was not disputed that the objective elements of the offences had been proved beyond reasonable doubt.
The issues to be determined are as follows:
1.Was Ms Somerville suffering from a mental impairment at the time of the conduct and, as a consequence of that mental impairment, did she not know that her conduct was wrong?[1]
2.Was the mental impairment that gave rise to mental incompetence, substantially caused by self-induced intoxication.[2]
3.If the mental impairment was substantially caused by self-induced intoxication, and notwithstanding s 269C(2) of the Act, should Ms Somerville be dealt with under Part 8A of the Act?[3]
[1] Criminal Law Consolidation Act 1935 (SA) s 269C(1)(b).
[2] Ibid s 269C(2).
[3] As permitted by s 269C(3) of the Criminal Law Consolidation Act 1935 (SA).
The determination of each of these issues requires analysis of Ms Somerville’s mental health history, substance abuse, and her conduct leading up to and constituting the alleged offending.
The events of 15 August 2022
At about 11.25 pm on 15 August 2022, Joshua Smith was driving southbound on the North-South Motorway, Wingfield when he observed a silver car stopped half over into the hard shoulder of the road and noticed that the passenger door was open. As he got closer to the vehicle, he observed a female (Ms Somerville) on the roadway on the passenger side of the car. Mr Smith called out to Ms Somerville to see if she was okay. He did not receive a response and as he drove past, he looked in his passenger side mirror and could see two young children lying on the ground with Ms Somerville moving down towards them.
Mr Smith pulled over and got out of his car to check on Ms Somerville and the children. As he began to walk towards her, he observed that one child was lying on the ground with their head towards the front passenger door and the other child was lying on the ground with their head towards the rear door. He saw blood around the younger child’s head and the older child had blood on his arms. Mr Smith initially thought that Ms Somerville was hitting the children, but as she faced him, he saw that she had a knife in her right hand and realised that she had been attacking the children with the knife.
Mr Smith told Ms Somerville to drop the knife, however, she held it towards him and threatened to stab him if he came any closer. Mr Smith managed to wrestle the knife from Ms Somerville and threw it away. As Mr Smith attempted to restrain Ms Somerville on the ground she managed to twist away and deliberately kicked out with her legs at the older child, connecting with the side of their head three or four times.
In response, Mr Smith picked Ms Somerville up, moved her away from the children and managed to again restrain her on the ground.
Throughout these events, Ms Somerville was yelling at Mr Smith to kill her. She was also saying that she needed to kill the children before they killed her. Mr Smith observed that although Ms Somerville’s words were clear, she was changing the subject matter quickly and was not able to stay on one topic or focus.
Shortly after, another male stopped and Mr Smith instructed him to call the police.
A number of police officers descended on the scene. Ms Somerville’s appearance and conduct was captured by various body worn cameras. She was often rambling and unintelligible. She was heard to say:
a.“I need my medication”;
b.“I’m not your daughter, I’m not you sister”;
c.“…I’m proud of what I did”;
d.“I’ve been targeted by every one of you, because you have been raping us and molesting us”;
e.“I’m stabbing every one of you, keep away from me”;
f.“Please take care of my babies, they will always be my babies”;
g.“I sucked a few of your friends off”;
h.“I’m feeling psychotic. I need my medication….I have my medication here, give it to me”;
i.“I’ve had so many drugs, I have all the drugs in my system…James Nash please, I have bipolar disorder…I have bipolar, I go to James Nash. That’s where I belong…give me my medication…I’m going to flip out again…I need my medication, I need my medication”.
Ms Somerville also claimed to have “meth” in her bra and said “someone put it in there…maybe you”.
Police searched Ms Somerville and located a small bag of white powder inside her bra.
In addition, pills including Valporic acid, Lurasidone and Olanzapine were located in her tracksuit pocket.
Ms Somerville became agitated, shouted at police and the paramedics, and had to be restrained and sedated.
The injuries
The two children were Ms Somerville’s sons, AG, who at the time was eight years old, and MS, who was three years old.
As a result of this attack both children presented with an extensive number of injuries, predominately skin incisions, lacerations and abrasions.
AG sustained 25 incisions, three lacerations and 40 abrasions to the head, face, neck, chest and both arms and hands. AG’s injuries were complicated by the embedding of the fractured tip of the blade of the knife into his skull, requiring neurological intervention.
MS sustained 14 incisions and 18 abrasions to his head, face, neck, back, chest and left arm. MS’s injuries were complicated by a left sided pneumothorax and lung laceration.
Intoxication
The small bag of white powder located in Ms Somerville’s bra was analysed. It weighed 0.09 grams and contained methylamphetamine.
A blood sample was collected from Ms Somerville at 12.50 am on 16 August 2022. Analysis of that sample showed the presence of:
a.Methylamphetamine at a concentration of 0.39 mg/L (milligrams per litre of blood).
b.Amphetamine at a concentration of 0.038 mg/L.
c.THC at a concentration of approximately 7 µg/L (micrograms per litre of blood).
d.Carboxy THC.
e.Citalopram at a concentration of approximately 0.016 mg/L.
f.Droperidol at a concentration of approximately 0.021 mg/L.
g.Lurasidone at a concentration of approximately 0.8 µg/L.
A second blood sample was collected from Ms Somerville at 2.42 pm on 16 August 2022. Analysis of that sample showed the presence of:
a.Methylamphetamine at a concentration of 0.16 mg/L.
b.Amphetamine at a concentration of 0.024 mg/L.
c.THC at a concentration of approximately 6 µg/L.
d.Carboxy THC.
e.Lurasidone at a concentration of approximately 1.1 µg/L.
Analysis of a urine sample collected at 2.47 pm on 16 August 2022 showed the presence of methylamphetamine, amphetamine, citalopram, droperidol, lurasidone, carboxy THC and olanzapine.
The olanzapine, lurasidone, and droperidol play no role in the determination of the issues before the Court.
Olanzapine and lurasidone are antipsychotic drugs that Ms Somerville had been prescribed. The evidence was that they would have had no significant effect on the state of mind of Ms Somerville at the relevant time.
Droperidol is another antipsychotic drug used to sedate anxious, agitated or disturbed patients as it is fast acting, with onset effects in three to five minutes. Ms Somerville was administered droperidol by SA Ambulance Service paramedics on 15 August 2022 shortly after their arrival at the scene.
The amphetamine present in the samples is most likely to be a metabolite of methylamphetamine and the detection of carboxy THC is likely a metabolite of THC.
The drugs that had the most significant impact on Ms Somerville were methylamphetamine and THC. I will come back to evidence about the nature of the impact when I come to consider the evidence and reports of Dr Nambiar, Dr Raeside, Dr Brereton and Professor White.
Ms Somerville’s personal circumstances
Mental health
Ms Somerville has a history of poor mental health. Her first contact with mental health services was in 2016 at the age of 30, when she was admitted to a psychiatric ward following a “mental breakdown”. She reported feeling manic and depressed at the same time and was “not coping”. Her mental state had deteriorated some weeks to months before the admission. She was diagnosed with a Bipolar Affective Disorder.
Ms Somerville was readmitted to psychiatric hospitals between 26 July 2017 and 26 August 2017, with a diagnosis of Bipolar Affective Disorder and a manic psychosis.
There was a further admission between 16 November 2017 and 23 November 2017 as a consequence of Ms Somerville overdosing on medication and cutting her arms.
Ms Somerville was again admitted to hospital between 13 June 2021 and 7 July 2021, having taken another overdose of her medication. She was diagnosed as suffering from a manic relapse of her Bipolar Affective Disorder.[4] Whilst in hospital, Ms Somerville was described as having ongoing persecutory delusions. When treated with antipsychotic medication, her delusions resolved.
[4] Prior to the overdose, Ms Somerville had deteriorated over a two to three month period with increased social isolation and presentations to her general practitioner with various somatic concerns.
Ms Somerville described her mental state as “okay” in early 2022, but that it began to “unravel” in early June 2022.
Ms Somerville last saw her treating psychiatrist in the community on 27 July 2022, at which point her mood was said to have improved and there was no evidence of manic symptoms. The community psychiatrist also observed there was no evidence of any psychotic features.
Alcohol and drug history
The following summary of Ms Somerville’s alcohol and drug history is a composite of the accounts that she provided to Dr Nambiar, Dr Raeside and Dr Brereton.
Alcohol
Ms Somerville described herself as a “social” drinker and denied any misuse of alcohol.
Cannabis
Ms Somerville commenced using cannabis at the age of about 14 or 15. She told Dr Brereton that she had used cannabis “on and off” ever since. She said that she sometimes had periods of abstinence, but there would also be periods when there was daily use.
Ms Somerville told Dr Nambiar that for most of her life she had smoked cannabis on a daily basis. She further reported that she was raised in a family where she was surrounded by drug users and she would use as much cannabis as she could get hold of because it relaxed her, consuming up to 10 bongs per night.
Similarly, Ms Somerville reported to Dr Raeside that she would smoke approximately five to 10 bongs each night throughout much of her life.
Methylamphetamine
Ms Somerville told each of the psychiatrists that she had first used methylamphetamine at the age of 30. She told Dr Brereton that she had used it sporadically up until the time of her arrest. She reported that, in total, she had only used methylamphetamine “a handful of times”.[5] She further reported to Dr Brereton that she had used methylamphetamine the day before the offending but had not used it in the 12 months preceding. She said that she had only used it three times in her life.
[5] Report of Dr William Brereton dated 20 September 2023 at [27].
Ms Somerville reported to Dr Brereton that methylamphetamine use kept her awake, but she did not believe that it made her paranoid or anxious. However, she said that she believed she would become unwell, “slip into mania”[6] and then, as a result, use drugs which in turn made her mental state worse.
[6] Ibid.
Ms Somerville told Dr Nambiar that she was introduced to methylamphetamine at the age of 30 and had her first “hit” on New Year’s Eve. She explained to Dr Nambiar that “it changes you, it makes you aggressive and paranoid”.[7] Based on his interview with Ms Somerville, Dr Nambiar remained unclear about her pattern of use.
[7] Report of Dr Narain Nambiar dated 1 May 2023 at [7].
Ms Somerville reported to Dr Raeside that she began “dabbling” in methylamphetamine at the age of 30. She had not tried it previously, and said that she had only used it sporadically. Ms Somerville acknowledged that it made her “paranoid and spiral out of control and worried more about paedophiles and people hurting [her] children”.[8]
[8] Report of Dr Craig Raeside dated 22 November 2022 at [14].
Events leading up to 15 August 2022
Ms Somerville sold her home in May 2022, but was permitted to remain in the house until 9 August 2022. Facing homelessness, she moved in with her ex-partner, JS (father of MS).
Around August 2022, Ms Somerville’s mental state started to deteriorate. Ms Somerville began to express beliefs that JS was having a sexual relationship with her friend. This culminated in an incident at a shopping centre on 14 August 2022, during which Ms Somerville accused JS of having an affair with the friend. The altercation escalated resulting in Ms Somerville resorting to violence, punching JS to the head.[9] The following day, on 15 August 2022, Ms Somerville sent JS text messages saying that she had broken into his house and damaged property.
[9] JS also alleges that Ms Somerville stabbed him in the hand with a pen. Ms Somerville denies this allegation. This is not a matter that I need to resolve as it does not assist in the resolution of the relevant issues.
Kathleen-Annabell Abrook, a family friend of Ms Somerville, offers a degree of insight into Ms Somerville’s mental health over this period of time.
Ms Abrook described Ms Somerville talking about receiving calls from JS during which she said he was talking about the children being aliens and “there were tracking devices up their bottoms”.[10] Ms Abrook’s concerns were such that she offered for Ms Somerville to come and stay with her. As a result, Ms Somerville and the children stayed at Ms Abrook’s house in the days leading up to 15 August 2022.
[10] Affidavit of Kathleen-Annabell Abrook dated 16 October 2022 (‘Abrook Affidavit’) at [2]. Ms Somerville does not dispute that she expressed concerns about tracking devices, but denies any reference to them being placed in the children’s bottoms. This difference of accounts is of no significance in determining the relevant issues.
During that time, Ms Abrook observed Ms Somerville cutting up her children’s toys, claiming that JS had put tracking devices inside of them. Ms Abrook also saw Ms Somerville slap AG to the head, which she described as out of character and inconsistent with the manner in which Ms Somerville usually treated her children.
Ms Abrook stated that Ms Somerville is “normally a beautiful, caring, loving mother and she will do anything for her kids”, but that she had become “manic”. On 14 August 2022, Ms Abrook called the police, as she was concerned about Ms Somerville’s mental health.[11]
[11] Ibid.
Ms Abrook noted a further deterioration in Ms Somerville’s condition the following day. Ms Abrook observed that on 15 August 2022, at about 10.30 pm, after Ms Somerville had a phone call with JS, she was “very much heightened” and “manic”. Ms Somerville smashed a laptop on the front driveway and told Ms Abrook that she would leave with the children and stay in a caravan park. Ms Abrook resisted them leaving, she said “I did not want the kids to go because she was so manic” however, they eventually left.[12]
[12] Ibid at [4]. Ms Somerville denies that Ms Abrook attempted to stop her from taking the children. This is another factual inconsistency that it is unnecessary for me to resolve.
In her interviews with the psychiatrists, Ms Somerville has provided an account of the events leading up to 15 August 2022.
Ms Somerville described the Friday before the alleged offending as unremarkable. She said, however, that on Saturday 13 August 2022 she argued with JS and cut up two of his t-shirts. JS called the police. He and his brother left the house, and told Ms Somerville to leave whilst they were gone. Ms Somerville packed up some food and important documents and placed a small paring knife into the box to use with food.
Ms Somerville drove to Ms Abrook’s house later that evening. She did not sleep that night. On Sunday, after the children woke up, Ms Somerville arranged to meet JS at the shopping centre. After meeting with JS, they then drove back to Ms Abrook’s house together. Ms Somerville claims that JS picked up some screw drivers and threatened her, so she hit him as hard as she could. She reported to Dr Brereton that she was not making good decisions at the time. [13]
[13] Report of Dr William Brereton dated 20 September 2023 at [30].
Drug use leading up to 15 August 2022
Ms Somerville and Ms Abrook have provided different accounts about the circumstances of Ms Somerville’s consumption of methylamphetamine leading up to the critical events on 15 August 2022.
Ms Abrook’s account
Ms Abrook said that on 15 August 2022, she became aware that Ms Somerville had withdrawn a large amount of cash. Ms Somerville tried to give her $1,000, however Ms Abrook refused to take it.
Later that day, Ms Somerville left the house with a person called BT. When she returned Ms Abrook became aware that Ms Somerville had purchased an ‘8 ball’ of methylamphetamine.[14]
[14] Abrook Affidavit at [3].
On 16 August 2022, Ms Abrook found drug paraphernalia in the bathroom, and suspected that Ms Somerville had smoked methylamphetamine.[15]
Ms Somerville’s account
[15] Ibid at [4]. This point is also disputed by Ms Somerville.
Ms Somerville similarly described withdrawing a large amount of cash. She however, reported to Dr Brereton, that she drove Ms Abrook and her partner to their dealer. The children were present but remained in the car. They then returned to Ms Abrook’s house to use the methylamphetamine.
Ms Somerville told Dr Brereton that on the evening of Sunday 14 August, she smoked methylamphetamine and cannabis. She said that she did not recall that this had much effect on her other than “shutting off her feelings”, however, she again stayed up all night and did not sleep.[16]
[16] Report of Dr William Brereton dated 20 September 2023 at [31].
In his first report, Dr Raeside noted that Ms Somerville told him that she and the children stayed at Ms Abrook’s house on Saturday night. She acknowledged that she “smoked a little bit of meth” as well an marijuana because the owners of the house gave her two bags and she smoked one of them. She kept the other bag in her bra and denied using any on the Sunday or the Monday”.[17]
Professor White’s evidence about the consumption of drugs
[17] Report of Dr Craig Raeside dated 22 November 2022 at [17]. Emphasis in original.
Professor Jason White, a forensic pharmacologist, provided a report and gave evidence about the various drugs that were in Ms Somerville’s system.
Professor White was also asked to undertake a ‘count back’ in order to provide an opinion as to the likely level of drugs that were in Ms Somerville’s system at the time of the alleged offences. There was no challenge to the evidence of Professor White. It is therefore unnecessary for me to descend into the details of the methodology used to arrive at this count back figure. Suffice for now to say that based on Professor White’s knowledge of the drugs in question, and how they metabolise in the body, Professor White was able to utilise the various test results to provide an opinion on the level of drugs likely to have been present in Ms Somerville’s system. It was his evidence that at the relevant time, Ms Somerville was likely to have had a concentration of approximately 0.43mg per litre of methylamphetamine and 7 micrograms per litre of cannabis in her blood.
Whilst the majority of the evidence of Professor White related to the impact that various drugs, both individually and in combination, may have had on Ms Somerville, he was also asked some questions about how much methylamphetamine Ms Somerville must have consumed over that period of time to arrive at the level that was present in her blood and urine samples.
This topic was first introduced in Professor White’s cross-examination when Ms Somerville’s counsel, Mr Powell asked Professor White the following:[18]
[I]s there any way, based on the different readings that you’ve observed, to say anything about when it was that methylamphetamine use occurred or over what period of time or when it ceased in the hours or days before the incident.
[18] 5 August 2024 T36-37.
Professor White responded that in the abstract, he could not provide such an opinion. Mr Powell then asked Professor White to consider four scenarios. The first, was that the use of the methylamphetamine had occurred approximately 48 hours before the incident and no further methylamphetamine had been consumed since that time.[19] Professor White responded that this scenario was unrealistic on the basis that to still have a blood level of 0.43 after such a long time would have required Ms Somerville to have consumed the drug at such a high level, that it almost inevitably would have been fatal.[20]
[19] This scenario was based on the account provided by Ms Somerville that Dr Raeside noted in his report of 22 November 2022 at [30].
[20] 5 August 2024 T37.
Mr Powell then asked Professor White to consider a second scenario that involved Ms Somerville consuming the methylamphetamine 24 hours prior to the relevant incident. Unlike the previous scenario, Professor White conceded that this was a “possibility”. When asked about what level of methylamphetamine must have been in Ms Somerville’s blood 24 hours before to reach 0.43, Professor White responded:[21]
If you base it on an average rate of metabolism, then you’re probably looking at a concentration over 1.5 or 1.6 mg per litre. So those are concentrations that are occasionally found. They certainly are associated with a risk of fatality. The only instances I’ve come across with concentrations that high, people have been acting in quite an aggro manner, their behaviour is clearly grossly affected.
[21] 5 August 2024 T37-38.
He further elaborated:[22]
… the only instances I’ve seen where people have reached that level, their behaviour has been very grossly affected or there are reported instances where they’ve presented to emergency departments or have been taken to emergency departments.
[22] 5 August 2024 T38.
The third scenario that Mr Powell asked Professor White to consider was one in which Ms Somerville had commenced taking methylamphetamine the night before and continued using it during the day, leading up to the relevant incident. Professor White also agreed that this was also a possible explanation for the amount of the drug that was in Ms Somerville’s blood. He said that to take the drug in multi doses over a period of time, is a common way that people use methylamphetamine.
The final scenario that Mr Powell asked Professor White to consider was a one-off use sometime during the day of the incident. Professor White opined that whilst the amount of drug consumed would not have needed to be as high as if it had been used the night before, it still required a relatively high amount to reach 0.43 at the relevant time.
Mr Powell also asked Professor White a number of questions about the suggestion that all of the methylamphetamine consumed by Ms Somerville had come from an eight ball of methylamphetamine that she had purchased the night before the incident. It was Professor White’s evidence that there would be a sufficient quantity of methylamphetamine within an eight ball to produce a blood concentration of 0.43.[23]
Findings as to the methylamphetamine consumed by Ms Somerville in the lead up to the alleged offences
[23] 5 August 2024 T39.
It is not necessary (or possible) to resolve all of the conflicts in the evidence on the topic of the circumstances in which Ms Somerville came to use the methylamphetamine. However, there are a number of matters about which I have been able to make findings of fact. Those findings are as follows:
1.On Sunday 14 August 2022, Ms Somerville withdrew a large amount of cash which she used to purchase an eightball of methylamphetamine.
2.On the evening of 14 August 2022, Ms Somerville smoked cannabis and methylamphetamine.
3.Ms Somerville continued to use both drugs over the course of 15 September 2022.
4.It is not possible to say precisely when, and in what quantity, Ms Somerville used the drugs over the course of that day, other than it was sufficient to result in a concentration of approximately 0.43mg per litre of methylamphetamine and 7 micrograms per litre of cannabis in her blood at the time of the alleged offences.
The issues to be determined
1. Was Ms Somerville suffering from a mental impairment at the time of the conduct and, as a consequence of that mental impairment, did she not know that the conduct was wrong?
A defendant’s mental competence to commit an offence is to be presumed unless the Court finds to the contrary.[24]
[24] Criminal Law Consolidation Act 1935 (SA) s 269D.
The Director has conceded that Ms Somerville was mentally incompetent to commit the offences. Despite this concession, it remains for this Court to determine whether Ms Somerville’s mental incompetence is established by the evidence.
The opinions of Dr Raeside, Dr Nambiar and Dr Brereton are central to the determination of this issue.
Each of the psychiatrists spent considerable time with Ms Somerville and prepared comprehensive and detailed reports. I have been greatly assisted by the work that they have undertaken, and it is apparent to me that each of them were cognisant of the seriousness and complexity of this case.
Dr Raeside, Dr Nambiar and Dr Brereton concur in their opinion that at the time of the relevant incident Ms Somerville suffered a mental impairment and as a consequence did not know that her conduct was wrong; that is, she could not reason about whether her conduct, as perceived by reasonable people, was wrong.[25]
Dr Raeside
22 November 2022 report
[25] Criminal Law Consolidation Act 1935 (SA) s 269C(1)(b).
Dr Raeside diagnosed Ms Somerville as suffering from a Schizoaffective Disorder, which he described was a combination of Schizophrenia and Bipolar Disorder. He said that whilst she may also have some borderline and antisocial personality traits, he found no significant evidence to suggest that Ms Somerville has an underlying personality disorder.[26]
[26] Report of Dr Craig Raeside dated 22 November 2022 at [30].
Dr Raeside reported that Ms Somerville also has a Substance Use Disorder, particularly cannabis, which she smoked on a daily basis.
In this report, Dr Raeside expressed the view that there was considerable evidence to suggest that Ms Somerville’s mental state had been deteriorating for some time prior to the alleged offending.[27]
[27] Ibid.
Although acknowledging that he did not have all of the material necessary to be conclusive about whether each of Ms Somerville’s fears and concerns were delusionally based, Dr Raeside reported that: [28]
the nature and quality of her beliefs and their persistence over time, together with collateral history elsewhere, strongly suggest that many of her concerns about fears for her safety and being killed and poisoned are likely to be delusional in nature.
(Emphasis in original)
[28] Ibid.
Dr Raeside expressed the view that:[29]
… Ms Somerville was suffering from a relapse of Schizoaffective Disorder at the time of the alleged offending with prominent paranoid and persecutory delusional beliefs, extending to beliefs that her children were part of this conspiracy to kill her.
(Emphasis in original)
[29] Ibid at [31].
In terms of the legislative test, Dr Raeside found that there was no indication that Ms Somerville would have been totally unable to control her conduct,[30] although he suggested that there appeared to be quite a degree of disinhibition to her behaviour, with her experiencing difficulty retaining control when she was at the height of her psychosis.[31]
[30] Criminal Law Consolidation Act 1935 (SA) s 269C(1)(c).
[31] Report of Dr Craig Raeside dated 22 November 2022 at [31].
Dr Raeside also found that Ms Somerville knew the nature and quality of her actions,[32] however he expressed the view that she would not have known the wrongfulness of her actions[33] by virtue of the paranoid delusional beliefs and illness that she was suffering at the time. It follows that Dr Raeside was of the opinion that at the time of the relevant incident, Ms Somerville was mentally incompetent to commit the offences as she satisfied the test in s 269C(1)(b) of the Act.
4 May 2023 report
[32] Criminal Law Consolidation Act 1935 (SA) s 269C(1)(a).
[33] Ibid s 269C(1)(b).
In preparing his initial report, Dr Raeside did not have available to him the report of Professor White. He was subsequently requested to provide a further report, taking into account Professor White’s report and also the body worn footage that showed Ms Somerville’s presentation at the scene of the alleged offences.
Consideration of that additional material caused Dr Raeside to reconsider and change his earlier opinion on the issue of Ms Somerville’s mental competence. Dr Raeside explained the reason for the change in his position:[34]
Whilst it is likely that Ms Somerville had some psychotic symptoms at the time of the alleged offending that affected her judgment, I do not believe that she was so impaired as to be unable to know the nature and quality of her actions or be unable to control her actions. There is some indication of impairment regarding her knowledge of the wrongfulness of her actions, but she does also indicate some knowledge of wrongfulness (such as asking for a lawyer when asked about her children).
[34] Report of Dr Craig Raeside dated 4 May 2023 at [5].
Dr Raeside was clearly influenced by the high level of methylamphetamine present in Ms Somerville’s system at the relevant time. He noted that Professor White had reported that at the time of the alleged offending Ms Somerville had approximately ten times the “therapeutic” dose of methylamphetamine in her blood, consistent with amounts typically seen in intoxication of the drug in active abusers. Dr Raeside observed:[35]
… in Ms Somerville’s specific situation the level of methylamphetamine in her blood at the time of the alleged offending would have aggravated any pre-existing psychosis. But I would add, the high level would be sufficient on its own to produce the psychotic features, including delusions, aggression, impulsivity, and poor judgement.
[35] Ibid at [3].
In forming his opinion, Dr Raeside also placed some weight on the appearance of Ms Somerville in the footage from the police body worn cameras. He explained:[36]
The body worn footage of police officers who attended the scene shows Ms Somerville relatively settled, although agitated at times especially early on. She does not demonstrate marked features of psychosis such as psychotic thought disorder, delusional ideas, nor evidence of hallucinations. She asks for medication and to be taken to James Nash House.
25 October 2023 report
[36] Ibid.
On 25 October 2023, Dr Raeside prepared a third report in which he again considered the question of Ms Somerville’s mental competence. In preparation for that report, Dr Raeside was provided with copies of Dr Nambiar’s report dated 1 May 2023 and Dr Brereton’s report dated 20 September 2023.
Having considered the reasoning in the reports of his colleagues, Dr Raeside reverted back to his original opinion. He explained:[37]
Having reviewed my previous reports, as well as the reports of my colleagues I would alter the opinion in my second report back to my initial opinion in the first report. Ms Somerville was suffering the weight of psychosis to such a degree at the time of the alleged offending, that she would have been unable to know that her conduct was wrong, as perceived by reasonable people.
Significantly there had been a steady decline in her mental state with worsening of psychosis over some time, not only in recent hours or days. She had persistent delusional beliefs, that not only involved other people, but specifically her children as well. At the time of the alleged offending, her actions were consistent with the impairment in her ability to know the wrongfulness of her conduct.
I accept that this indicates Ms Somerville was in a more protracted psychotic state at the time of the alleged offending. Although I described this in my first report, I did not give as much weight to it in my second report.
Likewise, my previous comments in my second report about features that might suggest Ms Somerville has some knowledge of the wrongfulness of her conduct, such as asking for a lawyer, are important. But, in the total context of the nature of her mental state at the time of the alleged offending, I believe it is not sufficient to alter the opinion that she was unable to know that her conduct was wrong.
Of course, in the company of police restraining and arresting her at the scene, comments about a lawyer suggest an awareness she was in legal trouble, hence the request for a lawyer. Nevertheless, I accept it does not preclude the more likely notion she did not know her alleged conduct toward her children was wrong at the time.
I therefore would support a mental impairment defence in relation to the two counts of attempted murder.
(Emphasis in original)
[37] Report of Dr Craig Raeside dated 25 October 2023 at [5].
Dr Raeside continued:[38]
I find myself in agreement with Dr Brereton that although the illicit drugs were a substantial cause of Ms Somerville’s psychosis at the time of the alleged offending it would be appropriate to deal with the matter under Part 8A of the Criminal Law Consolidation Act. Both the weight and duration of Ms Somerville’s mental impairment were associated with psychosis secondary to her treatment resistant Schizophrenia, not just drug use. Indeed, her symptoms had been shown to be treatment resistant.
[38] Ibid at [6].
Although Dr Raeside did not explicitly state that he had reverted back to his initial opinions, that Ms Somerville was mentally incompetent at the time of the relevant incident, it is implicit from this passage of his report that he must have arrived at that conclusion.
Dr Nambiar
1 May 2023 report
Dr Nambiar considered that Ms Somerville has a Borderline Personality Disorder and also has a clear history of a Substance Use Disorder, particularly in relation to cannabis and alcohol.
Whilst Dr Nambiar noted that historically Ms Somerville had been diagnosed with Bipolar Disorder, he was less convinced of that diagnosis and believed that the onset of a primary psychotic illness such as Schizophrenia would be a better account for her paranoid delusions. Dr Nambiar expressed the view that Ms Somerville’s Schizophrenia has been complicated by drug induced episodes or changes in mood that have been short term but continue to result in her experiencing persistent paranoid delusional thoughts.
In considering the question of mental competence at the time of the relevant incident, Dr Nambiar summarised his opinion as follows:[39]
It is my opinion that at the material time of the offence Ms Somerville (a) knew the nature and quality of her conduct; (b) did not know that the conduct was wrong in the context of paranoid delusions that had escalated to the point that her judgement was completely impaired. This was heightened by her use of amphetamines. In my opinion, Ms Somerville could not reason whether her conduct, as perceived by reasonable people, was wrong.
(c) In my opinion although Ms Somerville was driven by delusions she still maintained the ability to some degree, to control her conduct but chose not to.
1 November 2023 report
[39] Report of Dr Narain Nambiar dated 1 May 2023 at [25].
On 1 November 2023, Dr Nambiar prepared a second report in light of the report of Dr Brereton dated 20 September 2023. In order to prepare the report, Dr Nambiar was also provided with information about Ms Somerville’s mental state since the relevant incident.
This information was of particular significance to Dr Nambiar, as although Ms Somerville had not consumed any illicit substances since her admission to James Nash House, her delusions remained persistent despite her abstinence from illicit substances. Dr Nambiar explained the significance of this information. He said:[40]
In my opinion, the issue of a drug induced episode of psychosis is less relevant given the fact that since her admission to the forensic hospital, there has been a persistence of her delusional thinking despite the absence of illicit substances for a significant period of time and that these symptoms are still present now despite the commencement of adequate medication to address her Schizophrenia.
[40] Report of Dr Narain Nambiar dated 1 November 2023 at [3].
On that basis, Dr Nambiar confirmed his earlier opinion that Ms Somerville had a mental impairment defence available to her, although qualified it by saying that “it is extremely difficult to quantify the extent to which her amphetamine levels gave rise to the offence itself”.[41]
Dr Brereton
[41] Ibid.
Dr Brereton provided a report and also gave evidence. His evidence very much mirrored his report, although on some topics he was able to elaborate and provide further clarification.
20 September 2023 report
In his report, Dr Brereton noted that Ms Somerville had previously been diagnosed with a Bipolar Affective Disorder, a Schizoaffective Disorder and Schizophrenia. However, like Dr Nambiar, Dr Brereton preferred a diagnosis of Schizophrenia because her psychosis (in the form of delusions) had been more prominent and persistent over time than any mood related symptoms.[42]
[42] Report of Dr William Brereton dated 20 September 2023 at [4.11].
In addition to this, Dr Brereton expressed the view that Ms Somerville has, at least, significant Borderline Personality Traits, and may have a diagnosis of a Borderline Personality Disorder as well as a substance use disorder/substance dependence disorder.[43]
[43] Ibid at [4.12]-[4.14].
In Dr Brereton’s opinion “at the time of the conduct alleged to give rise to the alleged offending, Ms Somerville was suffering from a mental impairment. That mental impairment was psychosis, characterised by extensive delusional thoughts”.[44]
[44] Ibid at [4.17].
Despite her mental impairment, it was Dr Brereton’s view that Ms Somerville knew the nature and quality of her conduct. That is, she knew she was attacking her children with an intention to kill them.[45] Dr Brereton also did not believe that Ms Somerville was totally unable to control her conduct.[46] He observed that she had weighed up other decisions, for example, abandoning her children by the road, before the alleged offending.
[45] Ibid at [4.18].
[46] Ibid at [4.19].
Consistent with Dr Raeside and Dr Nambiar, Dr Brereton however found the third limb of the test had been satisfied in that he formed the view that Ms Somerville did not know that her conduct was wrong. Dr Brereton explained:[47]
… Ms Somerville could not reason about whether the conduct, as perceived by reasonable people, was wrong. As a result of her delusions, she was convinced that attempting to kill her children was morally correct conduct in order to protect herself and to prevent a worse fate for the children (being abducted, tortured and killed by an organised paedophile gang). Despite not knowing her conduct was morally wrong, Ms Somerville was aware her actions were illegal; which explains comments she made such as asking for a lawyer or dismissing the prospect she might get bail.
[47] Ibid at [4.20].
Dr Brereton therefore concluded that Ms Somerville was mentally incompetent to commit the alleged offences.[48]
Dr Brereton’s evidence
[48] Ibid at [4.21].
In his evidence Dr Brereton confirmed his diagnosis of Schizophrenia, Borderline Personality Disorder and a Substance Dependence Disorder. He also reiterated that it was his opinion that as a result of this impairment (that being psychosis), Ms Somerville did not know that her conduct was wrong. Dr Brereton elaborated on the explanation that he provided in his report. He said:[49]
Yes. Because she had such severe delusions that were of a certain nature that was she thought that she was in danger, she thought her children were in danger of a fate worse than death, that they were being groomed to kill her and that once that was done, that they would be then abducted, tortured, ultimately killed by a paedophile gang and so in harming the children, she thought she was doing the right thing in the circumstances.
Conclusion – mental incompetence
[49] 6 August 2024 T59.
I accept the evidence of Dr Raeside, Dr Nambiar and Dr Brereton that at the time of the relevant incident Ms Somerville was suffering from a mental impairment and as a consequence she did not know that her conduct was wrong. It follows that Ms Somerville was mentally incompetent to commit the offences.
2. Was the mental impairment that gave rise to mental incompetence substantially caused by self-induced intoxication?
Counsel for Ms Somerville does not challenge a finding that self-induced intoxication was a substantial cause of Ms Somerville’s mental impairment at the time of the alleged offences. It remains, however, for this Court to assess whether the evidence supports such a finding.
Professor White’s evidence about the effect of the drugs consumed by Ms Somerville
The starting point for the consideration of this issue is the opinion of Professor White about the effect that the various drugs would have had on Ms Somerville during the relevant incident.
For reasons that I have already canvassed, the two operative and therefore relevant drugs for current purposes are methylamphetamine and cannabis. I will therefore solely focus on them in this analysis of the evidence.
The concentration of methylamphetamine in Ms Somerville’s blood
As I have previously set out, Professor White calculated that the concentration of methylamphetamine in Ms Somerville’s system at the time of the relevant incident would have been approximately 0.43 mg/L.
To give meaning to that concentration, Professor White compared it to a therapeutic use of the drug which normally has a concentration of 0.02 to 0.05 mg/L. In contrast, most recreational users of methylamphetamine achieve concentrations in the 0.1 to 0.5 mg/L range, although frequent users achieve much higher concentrations. Professor White explained that the concentration of methylamphetamine in Ms Somerville’s blood, at the time of the incident, would have been in the range achieved by people using the drug recreationally and was well above a level that has been shown to produce a range of physiological, and behavioural effects.
The general effects of methylamphetamine
Professor White explained that whilst methylamphetamine intoxication produces a number of effects perceived as positive or pleasurable, it also has a range of adverse effects. The pleasurable effects include:[50]
… feelings of euphoria, confidence and energy; fatigue is reduced and the need to sleep is diminished. An affected person may be more active and more talkative than would normally be expected. The high level of confidence may be associated with impulsive, risky or reckless behaviour. This impulsive behaviour may be relatively harmless and may be perceived as positive if it leads to effects such as increased social interaction, but may also lead to adverse consequences for the individual, such as instances of aggressive behaviour.
[50] Exhibit P2, Report of Professor Jason White dated 19 January 2023 at [3].
The range of adverse effects of methylamphetamine include mental and/or physical agitation, rapid speech, confused thinking, obsessive behaviour as well as irrational and erratic behaviour.
Professor White described that the effects of methylamphetamine change significantly during the latter part of an episode of methylamphetamine intoxication. He explained:[51]
… the affected person will begin to feel fatigue that may be apparent in their appearance and behaviour. At this time, the person’s mood will be depressed rather than elevated, and they may seem unmotivated and may have difficulty concentrating. These rebound effects (sometimes described as sub-acute effects) may continue for many hours after last drug use or, in the case of a regular user who ceases use, may progress to a withdrawal syndrome over the following days. Methylamphetamine withdrawal is characterised by sleepiness, fatigue, depressed mood, irritability, difficulty concentrating and excessive appetite. Many people will use a drug such as cannabis or a sedative drug during this ‘come down’ phase to help them cope with the rebound effects.
Methylamphetamine induced psychotic symptoms
[51] Ibid.
In his report, Professor White described how methylamphetamine can produce psychotic effects. He explained that these almost always include paranoia. He elaborated:[52]
The paranoia may be manifested as the person being highly suspicious or they may experience an intense fear. Often the suspicion or fear will seem irrational and possibly bizarre, but in some instances the person may express fears that are convincing to other people. The drug may also produce hallucinations and delusions, typically in association with paranoia. A person experiencing such effects may behave very irrationally and may be dangerous to themselves and to others. Reports of people who had used the drug suggest that tolerance does not develop to the psychotic effects and, instead, these effects may become more prominent with repeated use of the drug. Psychotic symptoms arising from methylamphetamine use are more likely to occur in people with a pre-existing psychotic disorder such as schizophrenia.
In most instances, psychotic symptoms due to methylamphetamine use will subside once the drug is eliminated form [sic] the body and the general effects of the drug have diminished. However, in some instances methylamphetamine-induced psychotic effects continue for periods of days, weeks or longer after last use of the drug.
[52] Ibid at [4].
Professor White also described how methylamphetamine use is commonly linked to aggression and violent behaviour. He explained that aggression and violence can arise in several ways:
Firstly, the likelihood of aggression is increased by methylamphetamine as a result of the increase in impulsive, risky or reckless behaviour. In some circumstances, such behaviour may include aggressive or violent acts. Secondly, aggression may occur if the affected person experiences paranoia as a result of methylamphetamine use. The paranoia can result in the person engaging in acts that they consider an appropriate response to a threat which they perceive, but which is not real.
To an observer, the aggressive behaviour of a person affected by methylamphetamine may seem irrational and inappropriate for the circumstances in which it occurs.
The effects of methylamphetamine on Ms Somerville
Professor White gave particular consideration to the effects of methylamphetamine, and the relevant circumstances as they related to Ms Somerville. He summarised the position in the following terms:[53]
The level of methylamphetamine in Ms Somerville’s blood would have been sufficient to induce a number of the effects described above.[54] Exactly which effects she experienced depends on a number of factors including when she last used the drug prior to the incident, the amount she used, the method of administration and her degree of tolerance to the effects of methylamphetamine. As a person diagnosed with schizophrenia, Ms Somerville was at elevated risk of experiencing psychotic effects as a result of her methylamphetamine use. In a person with an existing psychotic disorder, psychotic symptoms such as delusions, hallucinations and paranoia are more likely to occur and may be induced even at relatively low methylamphetamine concentrations.
The general effects of cannabis
[53] Ibid at [4].
[54] The reference to “a number of the effects described above” refers to the effects that methylamphetamine often produces which includes psychotic effects (including paranoia), hallucinations and delusions as well as aggression and violence. Ibid at 4.
In his report, Professor White provided a summary of the general effects of cannabis. He stated:[55]
Cannabis commonly produces an initial euphoria and stimulation, frequently observed as laughter and talkativeness, that is relatively short lived (minutes in duration and definitely less than one hour). This is followed by a longer lasting sedation (normally up to 4 hours after smoking); as a result, the person may be drowsy and may fall asleep.
Cognitive function is impaired by cannabis. Ability to concentrate or maintain attention is diminished and memory and learning are impaired. Cannabis-induced decrements have been shown consistently for performance on tasks involving hand-eye coordination, maintaining attention, time estimation and memory. The effects of cannabis mean that an affected person will have difficulty engaging in mentally demanding activities and their judgement and decision making are likely to be impaired.
Perception is altered by cannabis such that the person believes their perception to be improved, by objective measures typically show a slight worsening. Users also experience a slowed perception time.
Cannabis-induced psychotic symptoms
[55] Ibid at [5]-[6].
Professor White explained that cannabis use can sometimes result in psychotic symptoms. He said:[56]
Use of cannabis can sometimes result in acute psychotic symptoms that most commonly persist for the period of intoxication (typically around four hours, but up to seven hours, if a relatively large amount of cannabis is smoked) and then subside. The evidence for such effects comes from case reports and from experimental studies of the effects of cannabis in healthy volunteers. The relevant effects of cannabis can include paranoia, transient hallucinations, delusions, emotional withdrawal, disorganised thinking and impaired cognitive functioning. While mild symptoms of this nature are relatively common among cannabis users, acute psychotic episodes of a severity that would warrant medical treatment appear to be infrequent. There is evidence that such acute psychotic episodes are more likely to occur in people who have a pre-existing psychotic disorder. In addition, while cannabis use is usually associated with a reduction in the likelihood of violence, in people with severe mental illnesses such as schizophrenia, cannabis use has been associated with violence. Such reactions normally occur after a period of heavy cannabis use.
In some people, the psychotic symptoms induced by cannabis may persist for a period of time beyond the period of acute intoxication. This is sometimes described as cannabis-induced acute persistent psychosis, and it has been documented in case studies. Such persistent psychosis is believed to be a rare phenomenon.
The effects of cannabis on Ms Somerville
[56] Ibid at [6].
Based on the history of Ms Somerville’s cannabis use that Professor White had been provided, he believed that she would have developed tolerance to the effects of the drug. He said that whilst she may have experienced some effects of cannabis at the time of the incident, most of these effects would not have been pronounced.[57] He noted however, that as a person with Schizophrenia, Ms Somerville was at an elevated risk of experiencing psychotic effects resulting from the use of cannabis.
The combined effects of methylamphetamine and cannabis
[57] Ibid.
Professor White concluded his report by considering the combination of the effects of methylamphetamine and cannabis. He said:[58]
At the time of the incident Ms Somerville would have been experiencing significant effects of methylamphetamine and, as a person with schizophrenia, she was at high risk of experiencing the psychotic effects of methylamphetamine such as hallucination, delusions and paranoia. As a result of these effects, her behaviour may have been unpredictable and erratic. She was also at elevated risk of engaging in aggressive and violent behaviour as a result of her use of methylamphetamine. To others this behaviour may have appeared irrational and unpredictable.
In a person such as Ms Somerville with diagnoses of schizophrenia and bipolar disorder, use of methylamphetamine and cannabis can exacerbate these conditions and significantly reduce the effectiveness of medication used in their treatment. In particular, both methylamphetamine and cannabis can exacerbate symptoms of schizophrenia and methylamphetamine can produce a state of mania or exacerbate an existing manic state.
The psychiatrists’ evidence about self-induced intoxication
[58] Ibid at [9].
The evidence of the toxicology results and Professor White’s report were the foundation of the opinions of Dr Raeside, Dr Nambiar and Dr Brereton as to whether self-induced intoxication was a substantial cause of Ms Somerville’s mental impairment. All three psychiatrists agreed in their views that Ms Somerville’s recreational consumption of drugs, and in particular methylamphetamine, resulted in a mental impairment which was substantially caused by self-induced intoxication.
Dr Raeside
Whilst in his initial report, Dr Raeside expressed the view that he did not consider methylamphetamine to be a substantial cause of Ms Somerville’s psychosis and impaired thinking,[59] after receiving Professor White’s report he revisited that opinion.
[59] Report of Dr Craig Raeside dated 22 November 2022 at [31].
In his second report, Dr Raeside had shifted to the view that drugs (particularly methylamphetamine) were a substantial cause of Ms Somerville’s mental impairment.
In Dr Raeside’s third report, having read the reports of Dr Nambiar and Dr Brereton, Dr Raeside concluded:[60]
All three of us appear to acknowledge that the level of methamphetamine and cannabis in Ms Somerville’s blood at the time of the alleged offending was significant such that it would have been producing a substantial adverse impact on her mental state. Indeed, it could be seen that this was “fuelling” her psychosis further.
Dr Nambiar
[60] Report of Dr Craig Raeside dated 25 October 2023 at [5]-[6].
In his first report Dr Nambiar, having expressed the view that Ms Somerville could not reason whether her conduct, as perceived by reasonable people was wrong, identified that the issue remained whether, on the balance of probabilities, that the mental impairment at the time of the conduct, gave rise to the issue of whether the offence was substantially caused by self-induced intoxication.
Dr Nambiar went on to say:[61]
It is my opinion that Ms Somerville does have a mental impairment defence available to her, however, I still hold reservations about the extent to which the amphetamines gave rise to the conduct itself. In my view, the extremely high levels of amphetamines would have intensified already established delusions (in the context of schizophrenia) and then had an additional effect on her judgement with erratic behaviour that was aggressive and resulted in the offence.
(Emphasis in original)
[61] Report of Dr Narain Nambiar dated 1 May 2023 at [26].
Dr Nambiar did not directly address the question of whether self-induced intoxication was a substantial cause of Ms Somerville’s mental impairment in his second report. He went on however to make some pertinent observations. He said:[62]
In my opinion, at the material time during which the offence occurred, Ms Somerville was experiencing acute psychosis brought about by Schizophrenia and in my opinion this was exacerbated by the use of methamphetamines.
I agree with Dr Brereton in that Ms Somerville’s Schizophrenia was the primary factor in her alleged offending, the evidence for this lies in the history of many years of persistent delusions that are of a paranoid nature evolving from her suspicions regarding her former partner and over time as her Schizophrenia has further evolved, her delusions have extended to incorporate various other people close to her, including her children.
In my opinion, her actions at the material time of the offence, were based on her delusional construct at that time and it is difficult to determine whether she would have carried out those actions due to delusions alone, irrespective of whether she was intoxicated with methamphetamine or not. Even if the court were to determine that at the time of the conduct alleged to give rise to the offending, that Ms Somerville’s mental impairment (psychosis) was due to the combined elements of Schizophrenia and methamphetamine intoxication, and further that her offending was substantially caused by self-induced intoxication, I agree with Dr Brereton that the court may use its discretion and order that Part 8A of the Criminal Law Consolidation Act applies.
Dr Brereton
[62] Report of Dr Narain Nambiar dated 1 November 2023 at [3].
Dr Brereton’s report contains the most detailed analysis of whether Ms Somerville’s mental impairment was substantially caused by self-induced intoxication. Dr Brereton commenced by noting that “substantially caused” does not mean the primary cause, but rather, a cause that is important, material or significant. He went on to say:[63]
With the above in mind, I note Ms Somerville might be said to have more than one mental impairment, i.e. her psychosis and intoxication. However, this does not affect my opinion regarding mental competence as, in my view, it is the delusional beliefs arising out of the psychotic illness which pertain to issues of competence, while the intoxication is more relevant to the cause and severity of the psychosis.
In my opinion, Ms Somerville’s impairment at the time of the alleged conduct (psychosis) was substantially caused by self-induced intoxication. (See 4.6, 4.7, 4.8, 4.13, & 4.15.) The intoxication was the result of cannabis and methamphetamine use, but methamphetamine was the more significant contributory factor. While it is possible Ms Sommerville’s [sic] mental state may have been the same at the time of the alleged offending in the absence of substance use (given her diagnosis of schizophrenia), I believe it is very unlikely an individual can use cannabis on a daily or near daily basis, and also be acutely intoxicated with methamphetamine, without there being a significant effect on her mental state. As a result of her substance use, Ms Somerville’s psychotic symptoms would have been more severe and her levels of agitation greater (greater levels of agitation being both the direct result of intoxication with methamphetamine and the indirect result of more intense delusions). In addition, Ms Somerville’s history indicates a worsening of her psychosis directly after her methamphetamine use the day before the alleged offending (she was no longer able to remain in Ms Abrook’s house as she incorporated individuals there into her delusional system; she became more acutely concerned she was being tracked; she developed the delusions regarding the children being trained/groomed to kill her).
In summary, in my opinion, Ms Somerville was suffering from a mental impairment at the time of the alleged offending, could not reason about whether her conduct was wrong, and was not mentally competent to commit the offence. Her mental impairment was primarily caused by schizophrenia but it was substantially caused by self-induced intoxication, both at the time of the relevant conduct and in the days preceding it.
(Emphasis in original)
[63] Report of Dr William Brereton dated 20 September 2023 at [4.26]-[4.28].
Dr Brereton confirmed his position on this issue when he gave evidence. In considering the cause of Ms Somerville’s psychosis, Dr Brereton was asked whether she may have been labouring under more than one impairment, namely, the psychosis as a result of her schizophrenia and intoxication from methylamphetamine. Dr Brereton responded:[64]
That’s my understanding from the cases that I’ve read, that you might say both were potentially mental impairments, although from a psychiatric perspective, from my perspective, it’s the psychosis that is more relevant than the intoxication, is more relevant insofar as it affects the severity of the psychotic symptoms and the level of her agitation.
[64] 6 August 2024 T59-60.
Dr Brereton was asked to further explain what he meant by that. He said:[65]
So I was aware that the courts are saying ‘Well, your mental impairment might be a psychosis and/or it might be your intoxication’. If that’s the case, then from a legal perspective, I would be of the understanding that she has these two mental impairments, but from a psychiatric perspective and the way that I then formed my opinion as to whether or not she was mentally competent was to do with the psychotic symptoms. So the actual intoxication I don’t think had a direct effect on whether or not she was mentally competent. I think it was the effect that it had on her psychotic symptoms that is more relevant. The question of the intoxication I think is more relevant to the effect it had on the psychotic symptoms and then whether those psychotic symptoms meant that she was mentally incompetent.
[65] 6 August 2024 T60.
He told the Court that the two could not be separated and that they were inextricably intertwined.
The following exchange then occurred:[66]
Q.Would this be fair - and, again, you correct me if I’m wrong - at the time of the conduct, she could have had that psychosis in a mild form symptomatically being mild, bubbling along, but adding that methamphetamine to that psychosis has substantially caused the severity of the psychosis that we saw at the time of the offending.
A.Yes, I think that’s reasonable. I think there’s evidence that shows that she was having psychotic symptoms for some months leading up to the offence and that those were perhaps fluctuating a bit, so she might become more preoccupied with sort of her delusional ideas about paedophile rings and the involvement of her partner and then it looked, from my reading of the collateral information of her account, that those might subside a bit again but they’re always there in the background but then, as you come up to the time of the offence, if she then - it is theoretically possible that if you take methamphetamine and cannabis out of the equation, that you might still have the same picture, that she might have arrived through stress, for example, she lost her house, she was having conflict with her partner, that she might have arrived at that severity of psychosis independent of drug use but I think it’s very - I think it’s very unlikely that you can add in methamphetamine and cannabis, especially a significant quantity of methamphetamine, and say ‘This has not had an effect on her presentation on her mental state’. I think it’s so unlikely as to be almost not worth considering. So the fact that she had a background of psychotic symptoms and then had a substantial amount of methamphetamine and she was also chronically using cannabis, those all combined to give the picture that we saw at the time of the offence. So, yes, I agree, that you have a bubbling psychosis, you provide methamphetamine and it significantly exacerbates the symptoms that she was experiencing.
Q.Again, this is my wording, you agree or disagree, does meth effectively add fuel to the fire.
A.Yes, I’d agree with that.
[66] 6 August 2024 T60-61.
Dr Brereton was asked what matters he had taken into consideration in arriving at the view that Ms Somerville’s psychosis was substantially caused by self-induced intoxication. He explained:[67]
Lots of factors. It was the collateral information that I had that showed a longitudinal picture of substance use. It was the fact that Ms Somerville had presented to hospital in the past with acute symptoms in the context of substance use. It was her own account of her substance use immediately prior to the offence and it was, again, the collateral information, specific information regarding her drug use prior to the offence and then it was the testing and Professor White’s opinion and his report that confirmed that she had drugs in her system at the time of the offence.
Conclusion – was self-induced intoxication a substantial cause of the mental impairment?
[67] 6 August 2024 T62.
The question of whether or not a mental impairment is “substantially caused by” self-induced intoxication is a question of fact.
The combined effect of the evidence of Dr Raeside, Dr Nambiar and Dr Brereton clearly establishes, on the balance of probabilities, that the mental impairment that Ms Somerville experienced, at the time of the conduct that gave rise to the offence, was substantially caused by self-induced intoxication. I accept that evidence and find accordingly.
3. Given that the mental impairment was substantially caused by self-induced intoxication, and notwithstanding the prohibition contained in s 269C(2) of the Act, should Ms Somerville be dealt with under Part 8A of the Act?
If a person is found to be mentally incompetent to commit an offence because the conduct that give rise to the offence was substantially cause by self-induced intoxication, the person may not be dealt with under Part 8A (mental impairment) but may (if appropriate) be dealt with under Part 8 (intoxication).[68] This would result in the person, if found guilty, being tried and sentenced in a non-therapeutic context. That is they would be subject to the usual sentencing principles. The policy considerations underpinning this section are self-evident, in that the criminal culpability of someone who chooses to become intoxicated to such a significant extent may fall into a different category of defendant than others whose mental impairment brings them within Part 8A.
[68] Criminal Law Consolidation Act 1935 (SA) s 269C(2).
In Question of Law Reserved (No 1 of 2021),[69] Livesey JA discussed the distinction. He explained:
By striking the balance concerning “self-induced intoxication” in this way, the legislation emphasises the culpability, if not moral obloquy, of the defendant whose mental impairment is caused, substantially, by recreational drug use. This may be distinguished from the defendant whose mental impairment is caused by underlying mental infirmity or disease, even where the effects have only manifested as the result of a failure by a defendant to take the medication which the defendant well-knows will curb any risk of anti-social or violent behaviours. The defendant who fails to heed medical or other advice and who thereby fails or refuses to take the medication which will keep mental illness in check does not come within s 269C(2) of the CLCA. Whilst that may appear surprising to some, there are often many reasons why the mentally ill do not take or cannot keep taking prescription medication and, in many cases, the consequences are properly matters for the mental health authorities rather than the criminal law.
(Footnote omitted)
[69] (2021) 140 SASR 135 at [227].
Section 269C(3) of the Act provides the Court with the discretion of dealing with a person under Part 8A even though the mental impairment was substantially caused by self-induced intoxication. That section relevantly states:
(3)However, despite the fact that the judge is satisfied that the person’s mental impairment at the time of the conduct alleged to give rise to the offence was substantially caused by self-induced intoxication, the judge may nevertheless make an order that the person be dealt with under this Part after taking into account—
(a) the time and circumstances of when and how the intoxication caused the mental impairment; and
(b) the interests of justice; and
(c) whether the making of such an order would affect public confidence in the administration of justice.
By that provision, even if a Judge is satisfied that the person’s mental impairment at the time of the conduct alleged to give rise to the offence was substantially caused by self-induced intoxication under s269C(2), the Judge may, nevertheless, make an order that the defendant be dealt with under Part 8A.
The starting point is to observe that s 269C(3) appears as an exception to 269C(2). The ordinary consequence of a finding made under s 269C(2) is that a person not be dealt with under Part 8A but may (if appropriate) be dealt with under Part 8 of the Act.
Accepting this, the question becomes why, after taking into account the criteria set out in sub-paragraphs (a)-(c) the ordinary consequences should not prevail.
In Question of Law Reserved (No 1 of 2021),[70] Livesey JA made the following observation about s 269C(3):
The matters specified may be regarded as open textured, intended to meet a very broad range of potential circumstances. Although cases of unintended or accidental consumption are excluded by the definition of “recreational use”, other cases of intoxication may give scope for the exercise of leniency (s 269C(3)(a)). The most obvious of these are cases where the intoxication – or abuse of drugs – is regarded as pathological or has been caused by the defendant’s difficulties with underlying mental illness. Whether or not that is so will be a question of fact, assisted by an understanding of a defendant’s longitudinal history, medical records and medical attendances over time. In addition, the requirement that the “interests of justice” be considered necessarily requires that consideration be given to a broad range of matters (s 269C(3)(b)). Similarly, the requirement to address whether making an order “would affect public confidence in the administration of justice” requires that consideration be given to concepts such as fairness, integrity and impartiality (s 269C(3)(c)).
The breadth of the potential circumstances to be addressed under s 269C(3) reflects that determining where the limits of criminal responsibility may lie will often depend, in difficult s 269C(2) cases, on a finely-balanced, nuanced assessment of the interaction between self-intoxication and the causes of mental impairment. The task set by s 269C(3) is necessarily tied to the particular circumstances of the case. In addition, the evaluation of what will often be a complex mix of medico-legal issues must be undertaken in a manner that is both fair to an accused and so as to preserve the expectation in the community that a defendant will be held criminally responsible for offending conduct in appropriate circumstances. How best to ensure the protection of the community and punish the offender will also be an important consideration.
Whilst an order can only be made after addressing the matters specified by s 269C(3), the potential for a defendant to be dealt with under Part 8A, even if the defendant’s mental impairment was substantially caused by self-induced intoxication, is important. The presence of s 269C(3) tends to reinforce the intention that, where appropriate, the Court is empowered to deal with defendants with what might be described as a therapeutic approach under Part 8A even where they would, prima facie, be subjected to ordinary criminal liability for their conduct because s 269C(2) is satisfied. That is, s 269C(3) is intended to ameliorate the potentially harsh operation of s 269C(2). Giving work to s 269C(3) tends to reinforce the modern, flexible approach to determining the most appropriate means of addressing the criminal liability and illness of the mentally impaired.
(Footnotes omitted)
[70] Ibid at [229]-[231].
The matters to be taken into consideration in making this determination are comprehensive and inclusive, which is no doubt designed to capture the very broad range of circumstances in which a defendant may potentially find themselves. Whilst it is the combined effect of these consideration that must ultimately be taken into account, it is instructive to consider each separately.
The time and circumstances of when and how the intoxication caused the mental impairment
It would appear that whilst historically Ms Somerville was a heavy user of cannabis, her experience with methylamphetamine was more recent and limited.
Ms Somerville commenced consuming methylamphetamine the night before the relevant events, however the evidence is that her mental health was already in a state of significant decline. This was consistent with a history of previous methylamphetamine use leading to the deterioration of her mental health, which is confirmed by her hospital admissions.
Dr Brereton gave evidence that it is probable that Ms Somerville was misdiagnosed, and she was likely suffering Schizophrenia. As such, she had a longitudinal history of mental illness, and her use of drugs was, in part, to relieve herself of the effects of her illness.[71]
[71] 6 August 2024 T62-63.
At the time of the relevant incident, Ms Somerville’s life was stressful and chaotic. She was homeless and feared losing custody of her children.[72]
[72] 6 August 2024 T91.
Ms Somerville found herself in the situation that was described by Kourakis CJ in Question of Law Reserved (No 1 of 2021) in that she was “driven by a misguided desire to alleviate the illness’ symptoms” and did not “foresee” that her drug taking would result in the commission of the crimes charged.[73]
The interests of justice
[73] (2021) 140 SASR 135 at [34].
The “interests of justice” is a broad concept, not amenable to precise definition or explanation, particularly because the concept is conclusionary in nature and will vary from case to case. In R v Tripodi,[74] Doyle CJ said that “the expression should be read as embracing a wide range of factors”.[75]
[74] (2002) 136 A Crim R 514.
[75] Ibid at [38].
Dr Raeside, Dr Nambiar and Dr Brereton have all expressed the opinion that Ms Somerville would be better treated, and the community better protected by her being accommodated and cared for in a mental health facility. On this basis, each of the psychiatrists have recommended that the Court deal with Ms Somerville pursuant to Part 8A.
Before dealing with the recommendations of the psychiatrists, it is worth mentioning the report that was obtained from Ms Somerville’s current treating psychiatrist, Dr Owen Haeney. That report was provided in response to a request from the Court regarding an update on Ms Somerville’s current mental state and her prognosis, and her likely future needs in terms of treatment and rehabilitation. In relation to the latter, Dr Haeney provided the following response:[76]
As stated, given the nature of the associated risks and ongoing symptoms, Ms Somerville’s treatment approach will be cautious. She will need ongoing treatment in hospital (if declared to be liable to supervision). This will involve further adjustments to medication in an effort to maximise effects, particularly for residual delusions, while minimising side effects. Psychological treatments will also be central to her rehabilitation plan, including psychoeducation, Cognitive Behavioural Therapy and DBT approaches. Additional therapies including social and occupational therapy will also be important.
[76] Report of Dr Owen Haeney dated 16 September 2024 at [3].
In his report, Dr Brereton described Ms Somerville’s psychotic illness as treatment resistant and that to date she still has persistent delusions despite being treated with clozapine (the medication reserved for use in treatment-resistant schizophrenia).[77]
[77] Report of Dr William Brereton dated 20 September 2023 at [4.16].
Dr Brereton went on to suggest that in those circumstances, Ms Somerville would be best dealt with under Part 8A. He said:[78]
I understand the existence of a mental impairment, and whether or not that impairment was substantially caused by self-induced intoxication, are questions of fact for the Court, and so I have tried to explain my understanding and reasoning when proffering an opinion. I also understand it is entirely for the Court to decide whether to use its discretion and order that Part 8A of the Criminal Law Consolidation Act applies, even if the mental impairment was substantially caused by self-induced intoxication. Therefore, it is with respect that I suggest Ms Somerville should be dealt with under Part 8A, even if she is found to have a mental impairment substantially caused by self-induced intoxication. This is because Ms Somerville suffers from a major psychotic illness (schizophrenia) which was the primary factor in her alleged offending. She had been suffering from psychotic symptoms to a greater or lesser degree for several years before the offending and her symptoms have proven to be treatment resistant. She remains unwell with significant psychotic symptoms. Her mental illness and her traumatic childhood experiences will have played a significant part in her maladaptive use of drugs to manage stress. From a psychiatric perspective, Ms Somerville requires ongoing treatment and rehabilitation. I believe Ms Somerville’s long-term treatment, rehabilitation, and the management of her risk, would be best managed under a disposal pursuant to Part 8A of the CLCA.
[78] Ibid at [4.29].
During his evidence, Dr Brereton went on to further explain:[79]
… I would support the decision if the court were to say that she should still be dealt with by part 8A and that’s because we know she has a severe major mental illness, she has severe schizophrenia, that even after many months of treatment, she was still ill, which means that her treatment and rehabilitation is going to take a long time. Also it’s going to take a long time because of the nature and gravity of the offence. Also, the fact that she was using drugs, as I mentioned before, was multifactorial, so her judgment was impaired by her psychosis. She also has had a traumatic childhood and upbringing, her personality traits have meant that she doesn’t cope very well with stress and she reaches for maladaptive ways of managing stress and the vicissitudes of life and drug use has been one of those things that she has turned to. So taking all of those factors into account, I would support disposal under part 8A because as well, I think, that in terms of her wellbeing, her welfare, but also the management of a long-term risk and protection of the public from harm, I think that’s going to be far better managed under a disposal under part 8A.
[79] 6 August 2024 T77.
Dr Nambiar agreed with Dr Brereton. In his addendum report he said:[80]
… Even if the court were to determine that at the time of the conduct alleged to give rise to the offending, that Ms Somerville’s mental impairment (psychosis) was due to the combined elements of Schizophrenia and methamphetamine intoxication, and further that her offending was substantially caused by self-induced intoxication, I agree with Dr Brereton that the court may use its discretion and order that Part 8A of the Criminal Law Consolidation Act applies.
Ms Somerville still requires ongoing treatment for what appears to be a treatment resistant form of Schizophrenia which requires specific expertise in the use of biological and psychosocial treatments that would be available to her within the forensic hospital. It would be in her best interests and to ensure that ultimately the community is safe after she is released.
[80] Report of Dr Narain Nambiar dated 1 November 2023 at [3].
Dr Raeside also agreed with Dr Brereton that the nature of Ms Somerville’s drug resistant Schizophrenia is such that she requires ongoing medical treatment. In his third report he explained:[81]
I find myself in agreement with Dr Brereton that although the illicit drugs were a substantial cause of Ms Somerville’s psychosis at the time of the alleged offending it would be appropriate to deal with the matter under Part 8A of the Criminal Law Consolidation Act. Both the weight and duration of Ms Somerville’s mental impairment were associated with psychosis secondary to her treatment resistant Schizophrenia, not just drug use. Indeed, her symptoms had been shown to be treatment resistant.
[81] Report of Dr Craig Raeside dated 25 October 2023 at [6].
It is clear that all the forensic psychiatrists who have been involved in this matter, agree that Ms Somerville continues to experience psychotic symptoms and is in need of ongoing treatment. It is in the best interest of the community that Ms Somerville receives that treatment and then, at the appropriate time, go through the usual step down regime for her eventual release back into the community under licence conditions.
It would seem to me that in those circumstances it is in the interests of justice that Ms Somerville be dealt with under Part 8A.
Would the making of such an order affect the public confidence in the administration of justice?
The maintenance of public confidence in the administration of justice includes notions of independence, impartiality, open justice, the publication of reasons and the application of judicial method, but it also requires an external perspective from which a decision can reasonably be seen to be justified.
The love and affection that a mother feels towards a child is unique and innate. There is no doubt that Ms Somerville was a loving and caring mother up until the time of the relevant events. In considering whether the making of such an order would affect the public confidence, a starting point must be that the public would accept that such abhorrent conduct by a mother, towards her children in a public place, is well beyond the normal human experience. Given Ms Somerville’s mental health history, the rational inference is that this conduct was the product of her illness, albeit the situation was compounded by her drug use.
It is clear that Ms Somerville has a treatment resistant form of Schizophrenia. Dr Brereton gave evidence about how that manifested itself in Ms Somerville’s conduct and her prognosis for the future.
In my view, in these circumstances, Ms Somerville’s moral culpability falls at the lower end of the scale. She did not use illicit substances for “dutch courage” or to in any way embolden her, but rather her use of drugs is explicable given her pre-existing mental illness, her background more generally, and the circumstances that she found herself in at that time. Despite treatment, and notwithstanding abstinence from any intoxicating substances, Ms Somerville’s delusional thoughts persist.
Counsel for the Prosecution and Ms Somerville agree that on the facts of this case there are nine critical considerations to the determination of whether the making of the order would affect the public confidence. These are:
a.Ms Somerville has a pre-existing mental illness, initially diagnosed as Bipolar Affective Disorder, but more recently diagnosed with Schizophrenia.
b.Since 2016 Ms Somerville has been treated, and at time hospitalised, for these conditions.
c.A back calculation undertaken by Professor Jason White determined that the concentration of methylamphetamine in Ms Somerville’s blood at the time of the conduct constituting the offending was approximately 0.43 mg/L.
d.There is no dispute that Ms Somerville was psychotic at the time of the conduct constituting the offending.
e.Further, the prosecution has conceded that, on the balance of probabilities, by reason of her psychotic state, Ms Somerville did not know that her conduct was wrong.
f.Ms Somerville has no prior convictions for violence.
g.Ms Somerville’s history reveals a pattern of psychosis, substance abuse and relapses.
h.The persistence of Ms Somerville’s mental illness in the months after her offending, despite abstinence from intoxicants and despite treatment, confirms the operative effect of her mental illness at the time of her offending.
i.The experts agree that Ms Somerville’s demise into psychosis and the contribution of methylamphetamine was like “throwing fuel on a fire”.
I agree that these are all matters that weigh heavily in favour of a Part 8A disposition of the matter. In my view, the rehabilitation of Ms Somerville is best assisted and the protection of the community best advanced by a therapeutic approach pursuant to Part 8A of the Act. To take such an approach in the unique circumstances of this case would not affect the public confidence.
Findings
I make the following findings:
1.The objective elements of the offences are established beyond reasonable doubt[82] (s 269G A(2)).
[82] Counsel for Ms Somerville conceded that the objective elements had been made out.
2.Ms Somerville was mentally incompetent to commit the two offences of attempted murder, as at the time of the relevant incident, Ms Somerville was suffering from a mental impairment and as a consequence did not know that her conduct was wrong (s 269C(1)(b)).
3.On the balance of probabilities, Ms Somerville’s mental impairment at the time of the conduct giving rise to the offences was substantially caused by self-induced intoxication (s 269C(2)).
4.Despite 3, having taken the relevant factors into account, it is appropriate that Ms Somerville be dealt with under Part 8A of the Act (s 269C(3)).
5.Ms Somerville is not guilty of the offences of attempted murder by reason of mental incompetence (s 269G B(3)(a)).
6.It is appropriate to declare Ms Somerville liable to supervision under Division 4, Subdivision 2 of the Act (s 269G B(3)(a)).
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