R v Krishna
[2023] NZHC 478
•10 March 2023
IN THE HIGH COURT OF NEW ZEALAND AUCKLAND REGISTRY
I TE KŌTI MATUA O AOTEAROA TĀMAKI MAKAURAU ROHE
CRI-2021-092-007369
[2023] NZHC 478
THE KING v
VIKHIL KRISHNA
Hearing: 27 February 2023 Appearances:
N E Walker and Y H Olsen for Crown
R M Mansfield KC, K J Brosnahan and O W L Troon for Defendant
Judgment:
10 March 2023
JUDGMENT OF ANDREW J
This judgment was delivered by Justice Andrew on 10 March 2023 at 2.30 pm
pursuant to r 11.5 of the High Court Rules 2016 Registrar / Deputy Registrar
Date ………………………………
R v KRISHNA [2023] NZHC 478 [10 March 2023]
Introduction
[1] On 27 February 2023, I gave a ruling on the admissibility of expert opinion evidence of Dr David Menkes, psychiatrist, who the defence had proposed to call as a witness. I ruled that Dr Menkes may give evidence generally about the effects of methamphetamine use and methamphetamine-induced psychosis. However, I concluded that much of the evidence proposed, and in particular his evaluation and assessment of the evidence in this case and his ultimate conclusion, was inadmissible.
[2]This judgment contains my reasons for those determinations.
Background
[3] The defendant was facing one charge of murder. The Crown alleged that the deceased died from neck compression by ligature strangulation and that blunt force head injury may also have contributed to her death. The defendant did not deny ultimately causing the deceased’s death. However, he denied any murderous intent. He acknowledged a culpable homicide but said that he was guilty only of manslaughter.
[4] The defence wished to call the evidence of Dr Menkes to suggest that at the time of the killing the defendant was suffering from a methamphetamine-induced psychosis and that based on previous episodes the defendant was vulnerable to such a psychosis. This was said to be an important contextual factor for the jury to assess whether the defendant had the necessary murderous intent.
[5] In his addendum report of 27 February 2023, Dr Menkes defined psychosis as a break or serious disruption in an individual’s perception of reality. This can include abnormal thinking, such as fixed, false beliefs known as delusions, which often but not always have a paranoid or persecutory flavour. He said that these disturbances can vary appreciably in their intensity and their duration, and accordingly in the extent of functional impairment.
[6] There were four reports from Dr Menkes about the defendant. That includes two dated 27 February 2023.
[7] Dr Menkes reviewed the defendant’s medical notes documenting admissions to Tiaho Mai (the mental health inpatient unit at Middlemore Hospital, Counties Manukau DHB) in December 2016 and June 2017. He said from the medical notes:
… We know that Mr Krishna experienced paranoid psychosis (including delusional thinking and irrational fear arising from faulty or exaggerated threat perception) as a consequence of drug use and has required treatment on two occasions. Not everyone who uses methamphetamine, even to the same level, will experience psychosis. However, we know Mr Krishna does and is therefore susceptible to this outcome.
[8] Dr Menkes’ report stated that susceptibility of an individual to psychosis following previous episodes is well established in clinical practice and has been documented in scientific literature.
[9] Defence counsel provided substantial evidence from the trial to Dr Menkes. That included a summary of the evidence relating to methamphetamine/drug use by the defendant and evidence of his symptoms and behaviour. He also received other evidence including CCTV footage, the transcript of the defendant’s 111 call on 11 September 2021 and the toxicology report of the Crown toxicologist, Ms Rosemary Moar.
[10] In his addendum report of 27 February 2023, and after reference to some of this evidence (including evidence of the defendant’s methamphetamine consumption and behaviour at the relevant time), Dr Menkes expressed the following opinion:
Taking this evidence together, I conclude that Mr Krishna was markedly affected by methamphetamine and likely to be experiencing symptoms and exhibiting signs of psychosis at the relevant time on 11 September 2021.
Relevant legal principles
[11] The admissibility of expert opinion evidence is governed by s 25 of the Evidence Act 2006. That section provides, relevantly:
Admissibility of expert opinion evidence
(1)An opinion by an expert that is part of expert evidence offered in a proceeding is admissible if the fact-finder is likely to obtain substantial help from the opinion in understanding other evidence in the proceeding or in ascertaining any fact that is of consequence to the determination of the proceeding.
…
(3) If an opinion by an expert is based on a fact that is outside the general body of knowledge that makes up the expertise of the expert, the opinion may be relied on by the fact-finder only if that fact is or will be proved or judicially noticed in the proceeding.
[12] In addition, expert opinion evidence must be excluded if the Judge considers that its probative value is outweighed by the risk that it would have an unfairly prejudicial effect or needlessly prolong the proceedings.1 In assessing the former risk, the Judge must take into account the defendant’s right to offer an effective defence.2
Analysis and decision
[13] The Crown objected to the admissibility of any evidence from Dr Menkes. It said that the threshold in s 25 of ‘substantial help’ was not made out; Dr Menkes’ evidence would add nothing to what was already before the jury, particularly in the form of the evidence of the Crown toxicologist, Ms Rosemary Moar. The Crown further said that Dr Menkes’ opinion as to the defendant’s state of mind/intent at the relevant time was inadmissible, as it lacked an evidential foundation and constituted an impermissible comment on the ultimate issue.
Issue (a) – Substantially helpful?
[14] I accepted that there was substantial overlap between the evidence of the Crown toxicologist, Ms Moar, on the effects of methamphetamine use and the proposed evidence of Dr Menkes. However, critically, Dr Menkes proposed to give evidence on the following two additional matters:
(a)The possibility of “drug-induced psychosis” or “methamphetamine- induced psychosis”;
(b)The contention that certain individuals may have a “predisposition” or vulnerability to experiencing methamphetamine-induced psychosis.
[15] Ms Moar is not a psychiatrist; she did not, of course, claim to be one. In this case, the defendant did have a documented mental health history, in particular his admission to Tiaho Mai in 2016 with methamphetamine-induced psychosis. It seemed
1 Evidence Act 2006, s 8(1).
2 Evidence Act 2006, s 8(2).
likely that the defendant was using methamphetamine at the time of the offending and Dr Menkes stated that an individual’s susceptibility to experiencing a further methamphetamine-induced psychosis following previous episodes is “well established” in clinical practice and is documented in the scientific literature. These factors all bore on the critical issue of murderous intent and were thus central to the defence case.
[16] I therefore found that some evidence from Dr Menkes, in particular the general effects of methamphetamine-induced psychosis and the potential predisposition of vulnerable individuals to such psychosis, would be substantially helpful to the jury. This general evidence is likely to fall outside the common knowledge of juries. It was likely to be substantially helpful given the uncontested mental health history of the defendant and the live issue of whether he might be predisposed to a further methamphetamine-induced psychosis.
[17] I now turn to address the second and critical issue; the extent to which Dr Menkes was able to comment on the significant evidence and facts in this case relevant to the issue of whether the defendant here may have been suffering from a methamphetamine-induced psychosis at the time of the offending.
Issue (b) – Evidential foundation
[18]In R v Makaore the Court of Appeal held:3
Before a court can assess the value of an opinion it must know the facts upon which it based. If no such basis is given, or, if given, can be seen to be speculative or irrelevant to the opinion expressed, then the opinion will be worthless.
[19] Where an expert opinion is based on facts not found in the general body of knowledge that makes up the expertise of the witness, those facts must be judicially noticed or proved in the proceeding.4
[20] The defence proposed that Dr Menkes could refer to the evidence already before the jury to demonstrate that the risk factors for methamphetamine-induced psychosis were engaged in this case. That included evidence that methamphetamine
3 R v Makaore [2001] 1 NZLR 318 (CA) at [24].
4 Evidence Act 2006, s 25(3); see also Tarapata v R [2016] NZCA 500 at [34].
consumption by the defendant and the deceased was substantial, repeated over the relevant period and that the defendant had been without sleep for an extended prior to the offending (i.e. on a “bender”). In support of his conclusion that Mr Krishna was “markedly affected by methamphetamine”, Dr Menkes proposed referring to the evidence of some of the defendant’s associates, who described him as being “fried” and “look[ing] blank” and evidence of Mr Krishna accusing his friend of either stealing his car or arranging for it to be taken.
[21] There was already substantial evidence before the jury on these critical factual issues, much of it anecdotal. This included extensive CCTV footage, texts and social media communications and observations of the defendant’s associates, police officers and other witnesses. These were all contested factual issues which bore critically on the ultimate issue of whether the defendant had the necessary murderous intent.
[22] Dr Menkes may well have been shown a substantial volume of this evidence. However, I agreed with the submission of Ms Walker that this was likely to be incomplete given the sheer volume of the evidence and the multiple sources. In any event, the critical point in making my decision was that Dr Menkes had no first-hand knowledge of these essential factual matters and no expertise or basis for usurping the jury function of evaluating and weighing all available evidence to determine the critical facts of the quantum of methamphetamine consumed, the duration of the consumption and the extent of any associated sleep deprivation. It would have been quite wrong for Dr Menkes to be able to rely on selected pieces of evidence and to present an opinion to the jury based on contested factual matters which were for the jury to decide.5 There was no basis to conclude that the evidence before the Court at that stage provided an uncontested and uncontroversial premise for him to express his expert view. I accepted there was repeated reference throughout the evidence to the use of methamphetamine and varying accounts as to the amount used. However, those were not facts found in the general body of knowledge that makes up Dr Menkes’ expertise – and, as noted, they were matters of evaluation, inference and weight for the jury to determine.
5 See Andrew Simester and Warren Brookbanks Criminal Law – A to Z of New Zealand Law (online ed, Thomson Reuters) at [20.11.2.1(1)], which states that the degree of an accused’s intoxication is exclusively a jury question, and no more than one matter to be taken into account in considering all the circumstances when reaching a verdict.
[23] Even if there were uncontested facts on the critical issues, namely the level of the defendant’s methamphetamine consumption and the nature of his behaviour, there would still have been limits on the ability of Dr Menkes to comment on the defendant’s understanding and awareness of his actions. In R v Taunga, Muir J held that experts such as psychiatrists should confine themselves to explaining the effects of alcohol and other drugs in general terms and not express an opinion on the ultimate issue of “voluntariness or intent”.6
[24] My conclusions are set out in the results section that follows. They are the conclusions that I set out in my earlier ruling of 27 February 2023.7
Result
[25]I found:
(a)Dr Menkes may give evidence generally about the effects of methamphetamine use and methamphetamine-induced psychosis. He may also give evidence about the potential predisposition of vulnerable individuals to methamphetamine-induced psychosis. I find that this evidence is substantially helpful and is admissible under s 25 of the Evidence Act 2006. However, much of the evidence contained in Dr Menkes’ latest report, namely dated 27 February 2023, and in particular his evaluation and assessment of the evidence in this case (e.g. quantum of consumption), and his ultimate conclusion,8 is inadmissible (as set out below);
(b)Dr Menkes can give evidence about what a psychosis is (as set out in section A of his addendum report of 27 February 2023);
(c)Dr Menkes may refer to the defendant’s admission to Tiaho Mai for methamphetamine-induced psychosis in 2016 as a diagnostic fact. He
6 R v Taunga [2017] NZHC 972 at [58] and [60]; citing Simon France (ed) Adams on Criminal Law
– Offences and Defences (online ed, Thomson Reuters) at [CA23.60]. See also R v Makaore, above n 3, at [21].
7 Ruling (4) [Result: Admissibility of defence evidence of Dr Menkes].
8 In [6] of the 27 February 2023 report.
may refer to the types of factors generally which might trigger a further methamphetamine-induced psychotic episode;
(d)Dr Menkes may discuss the 2017 admission to Tiaho Mai for synthetic cannabis use giving rise to auditory hallucination, provided there is a proper scientific and expert basis for concluding that this has a relevant connection to a subsequent possible methamphetamine-induced psychosis;
(e)Dr Menkes can give evidence that Mr Krishna may be susceptible to psychosis on the basis of his previous admissions to Tiaho Mai, “well- established” clinical practice and based on scientific literature;9
(f)Dr Menkes cannot give evidence as to whether the defendant was suffering from a methamphetamine-induced psychotic episode at the time of the alleged offending and what impact that had, in this case, on his judgment and/or any element of intention.10 Those are ultimate issue matters for the jury;
(g)Dr Menkes can express the view (as he does at [3] of his report of 27 February 2023) that risk factors generally for methamphetamine- induced psychosis can include past history, quantum of drug consumed, duration of consumption and the extent of associated sleep deprivation. However, any evidence commenting on, interpreting or assessing the facts of this case, where those matters are all at issue, is inadmissible. These are all disputed and interpretive matters for the jury to determine and not for Dr Menkes to comment on in any way;11
(h)Absent evidence from the defendant himself, Dr Menkes cannot give evidence as to the defendant’s substance use history as set out in his report of 10 February 2023;12
9 See [2] of the report of 27 February 2023.
10 This is not disputed by the defence.
11 This means that the reference to the recorded communications at [4] of the report of 27 February 2023 is inadmissible. So, too, are [5] and [7] of the report of 27 February 2023 (i.e. inadmissible). I note that the same inadmissible matters are repeated in section B of the addendum report of 27 February 2023.
12 Section C. Substance use history with reference to four points.
(i)Dr Menkes can give evidence of what types of behaviour generally an individual might exhibit if he was in a methamphetamine-induced psychotic state. That might include observations generally about misperception of a partner’s behaviour, inability to comprehend the consequences of actions and the impact of paranoia generally. Beyond that, and because many of the critical facts are at issue (of which Dr Menkes has no first-hand knowledge or expertise to assess), he cannot go. His conclusion in his report of 10 February 2023 that “there is little doubt” that Mr Krishna’s methamphetamine consumption played a significant role in the tragic events of 11 September 2021 goes too far. Likewise, he cannot say that Mr Krishna’s judgment was impaired at the material time and that it “is quite possible” that he misperceived his partner’s behaviour. Likewise, his conclusion that it was “likely” that Mr Krishna was experiencing elements of drug- induced psychosis at the material time, including paranoid thinking, irrational fear, etc, again goes too far as he does not have the evidential foundation for this;
(j)This means that the ultimate conclusion expressed by Dr Menkes at [6] of his report of 27 February 2023 is inadmissible. That paragraph reads:
Taking this evidence together, I conclude that Mr Krishna was markedly affected by methamphetamine and likely to be experiencing symptoms and exhibiting signs of psychosis at the relevant time on 12 September 2021.
Andrew J
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