Defence of mental health impairment or cognitive impairment

[6-200] Introduction

The defence of mental health impairment and/or cognitive impairment, formerly the defence of mental illness, is provided in the Mental Health and Cognitive Impairment Forensic Provisions Act 2020 (“the Act”) which commenced on 27 March 2021 and replaced the Mental Health (Forensic Provisions) Act 1990 (“the 1990 Act”).

For fitness to be tried, which is dealt with in Pt 4 of the Act, see [4-300] Procedures for fitness to be tried (including special hearings) which includes some general observations about some of the terms and concepts in the Act.

For the partial defence to murder of what used to be termed “substantial impairment by abnormality of mind” in s 23A of the Crimes Act 1900, see [6-550] Substantial impairment by mental health impairment or cognitive impairment.

The present chapter is concerned with the provisions of Pt 3 of the Act and what used to be referred to as the defence of mental illness and the special verdict of “not guilty by reason of mental illness” in Pt 4 of the 1990 Act. If the defence of mental health impairment and/or cognitive impairment in s 28 of the Act is established the special verdict that must be returned is “act proven but not criminally responsible”: s 30.

The Attorney General, the Hon Mark Speakman, said in the Second Reading Speech for the Mental Health and Cognitive Impairment Forensic Provisions Bill 2020 that Pt 3 updated and legislated what was the common law test for the defence of mental illness and rewrote the special verdict. The defence provided in what became s 28 was said to “closely mirror” the common law M’Naghten’s test “but with updated terms”: NSW, Legislative Assembly, Debates, 3 June 2020, p 2351. Consequently, authorities concerned with the mental illness defence at common law, for example, R v Porter (1933) 55 CLR 182, have continued relevance.

See generally, Criminal Practice and Procedure NSW at [17-s 28]–[17-s 34] and accompanying annotations; Criminal Law NSW at [MHCI.28.20]–[MHCI.28.240]. See also “Introducing the new Mental Health and Cognitive Impairment Forensic Provisions Act 2020”, The Hon Justice Mark Ierace, (2021) 33(2) JOB 15 and “Clinical issues with the Mental Health and Cognitive Impairment Forensic Provisions Act 2020”, Dr Kerri Eagle and Anina Johnson, (2021) 33(7) JOB 67.

[6-210] Transitional provisions

Savings and transitional provisions are made in Sch 2 of the Act, including the extent to which the Act may apply to existing proceedings. Clause 5 provides that if a question has been raised prior to the commencement of the Act as to whether the accused was mentally ill at the time of commission of the offence, the 1990 Act continues to apply until a determination is made as to whether a special verdict should be entered (or the defence is no longer being raised). If it is determined that the special verdict of not guilty by reason of mental illness would have been found, the court must instead find the special verdict of act proven but not criminally responsible. This is what occurred in Masters v R [2022] NSWCCA 228.

[6-220] Sequence of determination of issues

While it is theoretically necessary for the Crown to prove beyond reasonable doubt that the act (or omission) constituting the offence was a voluntary one, that is a matter that is presumed unless the accused discharges an evidentiary onus to indicate otherwise. If the issue is raised on the evidence it is then necessary for the Crown to prove beyond reasonable doubt that the act was a voluntary act of the accused: The Queen v Falconer (1990) 171 CLR 30 at 56, 63, 77. See [4-350] Voluntary act of the accused and [6-050] Automatism — sane and insane.

Where no issue is raised as to the voluntariness of the accused’s act, it is only necessary for the Crown to prove the physical elements of the alleged crime before the impairment defence falls for determination. That is, consideration of whether the mental element has been proved is only necessary if it is determined that the defence has failed: R v Tonga [2021] NSWSC 1064 at [15]; R v Siemek (No 1) [2021] NSWSC 1292 at [16]; R v Jawid [2022] NSWSC 788 at [97]–[98]. The proposition is traced to Hawkins v The Queen (1994) 179 CLR 500 at 512–517 and R v Minani (2005) 63 NSWLR 490 at [32]–[33]. In R v Jawid at [99]–[106], Davies J provided reasons for concluding that the issue of criminal responsibility must be considered before any question of substantial impairment.

It was held in Hawkins v The Queen at 512–513, 517 that medical evidence going to a defence of mental illness cannot be taken into account in determining whether an act is voluntary but may be taken into account in determining whether the act was done with a specific intent. Having regard to the rationale for this as explained by the High Court (at 513), this would appear to apply to both the mental health and the cognitive impairment defences.

[6-230] The impairment defence

Section 28 of the Act provides for a “defence” of mental health impairment, cognitive impairment “or both”.

While it is commonly referred to as a “defence”, it is not something that may only be raised by the accused. There are cases in which the Crown has contended the special verdict should be returned whereas the accused contended there should be an acquittal as a result of sane automatism (absence of voluntariness) or in a murder trial there should be a verdict of guilty of manslaughter by reason of substantial impairment because of mental health or cognitive impairment. The former was the case in R v DB [2022] NSWCCA 87 and the latter was the case in R v Jawid [2022] NSWSC 788. In R v Jawid, Davies J applied R v Ayoub [1984] 2 NSWLR 511 and s 28(2) of the Act in holding that the Crown is entitled to raise the issue of criminal responsibility by contending that the accused has a mental health impairment and that despite s 141 of the Evidence Act 1995, the standard of proof is on the balance of probabilities.

As to the reference in s 28(1) to “or both”, in their article referred to above, Eagle and Johnson observe (at 68) that mental health impairments and cognitive impairments may overlap clinically and diagnostically and the reference in s 28 (and in the test for fitness in s 36) to both “avoids the need for clinicians and courts to make potentially artificial determination as to which disorder is contributing to the relevant impairment”.

The terms, “mental health impairment” and “cognitive impairment” are defined in ss 4 and 5 of the Act respectively (and in identical terms in ss 4C and 23A of the Crimes Act). The definitions of mental health impairment and cognitive impairment each have three limbs set out conjunctively in s 4(1)(a)–(c) and s 5(1)(a)–(c).

The three subsections of s 4 comprise in subs (1) a definition of what is a mental health impairment; in subs (2) a non-exhaustive list of disorders from which a mental health impairment may arise; and in subs (3) an exclusion of two matters from solely giving rise to a mental health impairment (the temporary effect of ingesting a substance and a substance use disorder). Section 5 follows a similar structure in subss (1) and (2) but with terms and concepts relevant to cognitive impairment and without the exclusion of the temporary effect of ingesting a substance, or a substance use disorder.

It was held by a majority in R v DB at [43] that under the common law, the acts of a person who is asleep and engaging in somnambulistic activity are not willed acts. The accused was not legally responsible for them and would be entitled to an outright acquittal. It was further held (at [64]) that the Act did not alter this position in that there was no mental health impairment as defined in s 4: there was no disturbance of volition within s 4(1)(a) and the lack of volition while asleep was of no clinical significance for the purposes of s 4(1)(b).

It has been held in two single judge decisions that the onus of proof of the exclusion in s 4(3) is upon the Crown: R v Miller [2022] NSWSC 802 at [53]–[62] and R v Sheridan [2022] NSWSC 1669 at [20]–[26]. In the latter, the court rejected a proposition that the onus was upon the Crown to prove the matter beyond reasonable doubt and held that the standard of proof on the Crown was on the balance of probabilities. These matters appear to involve issues that were not considered and neither have the judgments been the subject of appellate review.

In R v Miller at [50]–[51], Cavanagh J held that an impairment by way of a substance induced disorder which existed at the time of the event which was temporary in nature, and which was caused solely by the ingestion of drugs without any underlying cause would be within the possible operation of s 4(3). He was not satisfied that the exception in s 4(3) could only apply where the accused was intoxicated by drugs at the time of committing the act or could never apply if s 4(2) is satisfied.

There are two limbs to the defence set out in s 28(1): R v Siemek (No 1) [2021] NSWSC 1292 at [84]–[86]. First, whether at the time of carrying out the act constituting the offence the accused had a mental health and/or cognitive impairment. Second, whether such impairment(s) had the effect that the accused did not know the nature and quality of the act or did not know that the act was wrong (that is, could not reason with a moderate degree of sense and composure about whether the act, as perceived by reasonable people, was wrong). It is presumed that the accused did not have either such impairment until the contrary is proved, with such proof being on the balance of probabilities: s 28(2)–(3). Whether the accused did not know the nature and quality of the act involves an assessment of whether the accused knew the physical nature of what he/she was doing or the implications of it: The King v Porter (1933) 55 CLR 182 at 188; Willgoss v The Queen (1960) 105 CLR 295 at 300.

The definition within s 28(1)(b) of not knowing that the act was wrong meaning that the accused “could not reason with a moderate degree of sense and composure about whether the act, as perceived by reasonable people, was wrong” adopts the formulation of Dixon J in The King v Porter at 189–190 which included his Honour saying that “wrong” meant “wrong having regard to the everyday standards of reasonable people”. It was confirmed in Stapleton v The Queen (1952) 86 CLR 358 at 375 that the issue is whether the accused was able to reason as to what is right and wrong according to the ordinary standards adopted by reasonable people as opposed to knowing that the act was contrary to and punishable by law.

[6-240] Evidence

There was no legal requirement to adduce medical evidence to prove the former defence of mental illness: Lucas v The Queen (1970) 120 CLR 171 at 174. However, it was observed in Tumanako v R (1992) 64 A Crim R 149 at 160 that there may be a practical necessity to do so and Johnson J noted in R v Siemek (No 1) [2021] NSWSC 1292 at [92] that it may be more than a practical necessity to have expert medical evidence for that part of the definition of a mental health impairment that a disturbance of thought, mood, volition, perception or memory “would be regarded as significant for clinical diagnostic purposes”. The same is likely the case about aspects of the definition of cognitive impairment. Juries (and judges sitting alone) are not bound to accept and act upon expert evidence but must not disregard it capriciously: R v Hall (1988) 36 A Crim R 368; Goodridge v R [2014] NSWCCA 37 at [116]. Unanimous medical evidence ought not be rejected unless there is evidence which can cast doubt upon it: R v Tumanako at 160–161; Da-Pra v R [2014] NSWCCA 211 at [337].

[6-250] Mandatory information for the jury

Section 29 provides that the judge must explain the matters listed in paragraphs (a) to (e) to the jury. They are the findings which may be made on the trial and their legal and practical consequences: s 29(a)–(b). Section 29(d) adds this includes that if the special verdict is returned, the accused may be ordered to be released by the Mental Health Review Tribunal only if the Tribunal is satisfied the safety of the accused and members of the public will not be seriously endangered. Section 29(c) provides the jury is to be informed about the composition of the Mental Health Review Tribunal and its functions in respect to forensic patients. Paragraph (e) provides the jury be told that it should not be influenced in the return of a verdict by the consequences of a special verdict. The provision of such instruction to a jury appears to have derived from R v Hilder (1997) 97 A Crim R 70 at 81. The Attorney General indicated in his Second Reading Speech stakeholders had asked that this requirement be retained so that a jury is not deterred from returning a special verdict out of concern about indeterminate detention: NSW, Legislative Assembly, Debates, 3 June 2020, at 2352.

The Mental Health Review Tribunal is constituted under Ch 6 of the Mental Health Act 2007 (provisions relating to membership of the Tribunal are found in Sch 5.) The functions of the Tribunal in relation to forensic patients who have been the subject of a verdict of act proven but not criminally responsible are contained in Pt 5 of the Act. Information included in the suggested direction at [6-280] for compliance with s 29 of the Act has been drawn from these sources.

[6-260] Fast track determination where parties in agreement as to outcome

Section 31 of the Act provides for a streamlined procedure enabling a court to enter a special verdict at any time in the proceedings, even before a jury is empanelled. It is necessary that the defendant is legally represented and that the parties agree that the proposed evidence establishes the defence in s 28. If the court is satisfied the defence is established the special verdict may be entered. There is no requirement that a trial be convened, that the defendant elect to be tried by judge alone, or that the judge comply with the requirements for such a trial under ss 132 and 133 of the Criminal Procedure Act 1986. It remains necessary for a judge to provide reasons for the outcome as a necessary function of judicial proceedings. See R v Sands [2021] NSWSC 1325 at [3]–[4]; R v Jackson [2021] NSWSC 1404 at [7]–[13].

[6-270] Verdict and orders

If the defence of mental health or cognitive impairment has been established, the jury must return the special verdict of act proven but not criminally responsible: s 30. Section 32 provides that if the special verdict is entered, there is no requirement for the special verdict to be entered also in respect of an offence available as an alternative.

The orders a court may make upon the return of a special verdict are set out in s 33(1). They include an order for the unconditional or conditional release of the person from custody but before making such an order the court must be satisfied that the safety of the person or any member of the public will not be seriously endangered: s 33(3).

The court may request a report by a forensic psychiatrist, or a person of a class prescribed by the regulations as to the condition of the person and whether their release is likely to seriously endanger the safety of themself or any member of the public: s 33(2). Clause 4 of the Mental Health and Cognitive Impairment Forensic Provisions Regulation 2021 prescribes for the purposes of s 33(2) a person who is a registered psychologist who has, in the opinion of the court, appropriate experience or training in forensic psychology or neuro-psychology. Section 30L of the Crimes (Sentencing Procedure) Act 1999 enables a victim impact statement to be provided to the court following the return of a special verdict at a trial or special hearing (and a verdict at a special hearing that on the limited evidence available an accused person committed an offence). This has been described as a “significant” and “important” reform: R v Siemek (No 2) [2021] NSWSC 1293 at [3], [6]–[7]. Any victim impact statement must be provided to the Mental Health Review Tribunal: s 30N(3). Section 30M provides that a court may seek submissions by the “designated carer or principal care provider” (as defined in the Mental Health Act 2007) of an accused person after the return of such a verdict. It is suggested that an inquiry be made as to whether any of these provisions should be applied before the court finalises a matter by making orders pursuant to s 33 of the Act. There must be a referral of the person to the Mental Health Review Tribunal if a special verdict is returned unless an order is made for the person’s unconditional release: s 34.

[6-280] Suggested direction

It is recommended that the jury be assisted by the provision of a document setting out the elements of the offence the Crown is required to prove together with the elements of the defence raised. A document setting out the composition and relevant functions of the Mental Health Review Tribunal in respect to forensic patients may also assist.

The suggested direction assumes the jury have been directed as to all of the elements of the offence the Crown is required to prove. It is based upon the more commonly encountered case in which there is no dispute that the accused committed the physical act constituting the offence and that the defence raised is one of mental health rather than cognitive impairment. The direction may be readily adapted if the case at hand is otherwise. A suggested substitution of an explanation of “cognitive impairment” to use in lieu of “mental health impairment” appears below.

If there is an issue as to whether the accused’s act was voluntary, the following direction should be preceded by a direction as to that, see [4-350] Voluntary act of the accused. If an issue of automatism arises as the basis of an assertion of involuntariness, see also [6-050] Automatism sane and insane.

If you are satisfied beyond reasonable doubt the accused committed the physical act that constitutes the offence, namely [specify], which the accused concedes, [where appropriate add: and that it was a voluntary act in the sense I have described] then you must decide whether it has been established that a special verdict of “act proven but not criminally responsible” should be returned. Whether or not the mental element of the offence that I have described, namely [specify] has been proved is irrelevant for the moment. The return of the special verdict which I am about to explain does not depend upon that mental element having been proved.

So, if you are satisfied the accused committed the act of [specify], the question then is did [he/she] have a mental health impairment which had the effect that [he/she]:

(a) 

did not know the nature and quality of the act, or

(b) 

did not know that the act was wrong.

If that has been proved, then you would return the “special verdict” which is “act proven but not criminally responsible”.

I will explain these concepts shortly but will first explain some important matters concerning what I will call this impairment issue.

First, unless there is some evidence to the contrary, the law presumes that an accused did not have a mental health impairment that had one of the effects upon him that I have mentioned.

Second, you are concerned with the mental health of the accused at the time of committing the act that constitutes the offence. There is evidence of the state of [his/her] mental health before and after but it is only relevant to the extent to which it assists in a determination of what the accused’s mental health condition was at the time of committing that act.

The third matter is that proof of this impairment issue is necessary only to the standard of the balance of probabilities. That stands in contrast to the requirement that the Crown prove the guilt of the accused to the standard of beyond reasonable doubt. I will say more about this in a moment.

I will now speak about the elements of the impairment issue itself. As I have said, it involves two matters: whether the accused had a mental health impairment at the time of carrying out the act constituting the offence and if so, whether this impairment had a certain effect upon the accused.

1. Mental health impairment

A person has a mental health impairment if each of the following three matters have been proved:

(a) 

the person has a temporary or ongoing disturbance of thought, mood, volition, perception or memory; and

(b) 

the disturbance would be regarded as significant for clinical diagnostic purposes; and

(c) 

the disturbance impairs the emotional wellbeing, judgment or behaviour of the person.

[It will often not be necessary to refer to every aspect of (a) and (c); only to those which have been specifically raised by the evidence.]

[Discuss each of these three matters in turn by referring to the evidence and the submissions of the parties.]

[Where appropriate add: A person does not have a mental health impairment if the person has an impairment caused solely by either:

(a) 

the temporary effect of ingesting a substance, or

(b) 

a substance use disorder.

[Discuss either or both matters by reference to the evidence and the submissions of the parties.]]

2. The effect of the impairment upon the accused

If you are satisfied that the accused had a mental health impairment at the time of carrying out the act constituting the offence, it is also necessary that this impairment had one or the other of the following effects:

(a) 

the accused did not know the nature and quality of the act, or

(b) 

the accused did not know that the act was wrong (that is, the accused could not reason with a moderate degree of sense and composure about whether the act, as perceived by reasonable people, was wrong).

As to the first of those matters, a person does not know the nature and quality of an act if they do not know of the physical nature of what they are doing, or do not know of the implications of doing that act.

The second matter is not concerned with whether the accused knew that the act was wrong in the sense of being something that was contrary to the law and punishable as a consequence. It is concerned with whether the accused was able to understand the difference between right and wrong as ordinary reasonable people are able to understand. This second matter will have been established if you are satisfied that the accused could not reason with a moderate degree of sense and composure about whether the act was wrong.

[Discuss either or both matters by reference to the evidence and the submissions of the parties.]

Standard of proof

I have mentioned that you have to decide on “the balance of probabilities” whether the accused had a mental health impairment that had a certain effect upon [him/her] as I have described. That means you have to decide this issue on the basis of what is more probable than not. This is a different standard or level of proof than beyond reasonable doubt which applies to what the Crown must prove in order to establish that the accused is guilty of the offence charged. The issue you are concerned with here is whether the accused had a mental health impairment which had one or other of the effects of [refer to the text of 2[a] or [b] above] upon [him/her]. It is only necessary for you to be satisfied that it is more probable that [he/she] did than that [he/she] did not. It does not matter how slightly it might be more probable, only that it is more probable by some degree.

Special verdict

If you are satisfied on the balance of probabilities that at the time the accused carried out the act of [specify] [he/she] had a mental health impairment that had the effect upon [him/her] as I have described, then you must return what is referred to as the “special verdict” which is “act proven but not criminally responsible”.

Explanation of the effect of the special verdict

[required to be given pursuant to s 29 of the Mental Health and Cognitive Impairment Forensic Provisions Act 2020].

You may be interested to know what happens when a jury returns the special verdict, and this is information that the law says you must be given.

If your verdict is “not guilty”, the accused walks from the court a free person and the criminal process comes to an end. If your verdict is “guilty”, the court will determine the appropriate punishment to impose upon the accused.

However, if you return the special verdict of “act proven but not criminally responsible”, neither of those things happens. Instead, the law provides for a process of review, to determine whether the accused poses a risk to him/herself or to others, and whether he/she should be released into the community or detained and treated.

If the court is satisfied that the safety of the accused and members of the community will not be seriously endangered by the accused’s release into the community, he/she can be released, either unconditionally, or with conditions, such as a requirement that the accused accept medical treatment, or live at a particular place. If the court concludes that it is not appropriate to release the accused into the community at present, the court can order his/her detention until it is safe to release him/her. Detention can be in a prison, or a secure hospital or some similar facility, and it would continue until a Tribunal, called the Mental Health Review Tribunal, decided that the accused could be released.

The Mental Health Review Tribunal is a special body with expertise in this area. It has Members rather than judges, but the Members of the Tribunal are all people with special qualifications and expertise. They include judges or senior lawyers, but also medical and other professionals, such as psychologists and psychiatrists.

The Tribunal will review the accused’s situation regularly and will not order the release of the accused until it is satisfied the safety of the accused or any member of the public would not be seriously endangered. Until that time, the accused would be held in a secure place, where medical treatment can be provided.

When you are considering the verdict(s) that you will return, it is useful for you to know what will happen if the verdict should be that of “act proven but not criminally responsible”. Giving you this information is not, however, an invitation to decide the case based upon what you think is the best outcome for the accused or the community. You must, consistent with the oath or affirmation you took on the very first day of the trial, return a verdict based only upon the evidence placed before you.

Upon determination of the impairment issue

You will be satisfied that the special verdict should be returned if you are satisfied on the balance of probabilities that at the time of carrying out the act of [specify] the accused had a mental health impairment that had the effect that the accused did not know the nature and quality of the act or did not know that the act was wrong.

In that case, provided you are satisfied beyond reasonable doubt that the accused carried out that act [where appropriate add: and that it was a voluntary act] your verdict will be: “act proven but not criminally responsible”.

If you are not satisfied on the balance of probabilities that this special verdict should be returned, then you must consider whether the Crown has proved the guilt of the accused by proving beyond reasonable doubt each of the essential elements of the offence that I have explained to you. .

[6-290] Suggested direction — cognitive impairment

The suggested direction for mental health impairment may be readily adapted for a case involving an issue of cognitive impairment (or both). The following is suggested for substitution of that part of the direction concerned with the nature of the impairment.

Cognitive impairment

A person has a cognitive impairment if each of the following three matters have been proved:

(a) 

the person has an ongoing impairment in adaptive functioning; and

(b) 

the person has an ongoing impairment in comprehension, reason, judgment, learning or memory; and

(c) 

the impairments result from damage to or dysfunction, developmental delay or deterioration of the person’s brain or mind.

[It will often not be necessary to refer to every aspect of (b) and (c); only to those which have been specifically raised by the evidence.]

[Discuss each of these three matters in turn by referring to the evidence and the submissions of the parties.]