NZLII Home | Databases | WorldLII | Search | Feedback

New Zealand Yearbook of New Zealand Jurisprudence

You are here:  NZLII >> Databases >> New Zealand Yearbook of New Zealand Jurisprudence >> 1998 >> [1998] NZYbkNZJur 6

Database Search | Name Search | Recent Articles | Noteup | LawCite | Download | Help

Wright, Fran --- "Does New Zealand need a diminished responsibility defence?" [1998] NZYbkNZJur 6; (1998) 2 Yearbook of New Zealand Jurisprudence 109

Last Updated: 15 April 2015

Fran Wright*

Murder is the most serious offence in New Zealand's Crimes Act 1961: put simply, it is the offence of intentionally or recklessly killing another person.' It carries a mandatory penalty of life imprisonment. The main defences to murder are self-defence, provocation and insanity. However, there are cases in which the formal definition of murder is clearly satisfied, to which none of these defences apply, and which nonetheless do not appear in the eyes of observers to warrant either the label murder or its mandatory penalty.

One cause of this discomfort with the New Zealand law of homicide is the narrow range of defences provided. In addition to self-defence, provocation and insanity, English law provides a defence of diminished responsibility that reduces murder to manslaughter in cases where mental abnormality results in partial responsibility. Several Australian states have enacted a defence along similar lines.2 From time to time, it has been suggested that the defence of diminished responsibility should also be introduced in New Zealand, allowing some offenders who would currently be convicted of murder to be convicted of manslaughter instead.' The maximum penalty for manslaughter is life imprisonment but there is no minimum penalty.4

This article looks at arguments for and against the introduction of a diminished responsibility defence, and concludes criminal law in New Zealand needs to be more sensitive to degrees of responsibility, but a diminished responsibility defence based on the English model is not the best way to do this.

BA (Hons) (Stirling), LLB (Auckland), Lecturer in Law, University of Waikato

1 See text above note 4 for a more detailed account of the offence of murder.

  1. There are similar defences in several Australian states: Australian National Territory (s14 Crimes Act 1900), Queensland (s304A Criminal Code 1984), New South Wales (s23A Crimes Act 1900) and Northern Territory (s37 Criminal Code (NT) 1983). The New South Wales provision was recently amended: see text above n71.
  2. Arguments in favour of diminished responsibility can be found in Brookbanks, W "Diminished Responsibility: Balm or Bane" in Legal Research Foundation, Movements and Markers in Criminal Policy (1984); Ablett Kerr QC, .1 "A Licence to Kill or an Overdue Reform?: The Case of Diminished Responsibility" (1997) 9 Otago LR I; and Bungay, R Scarecrows: Why Women Kill (1998).

4 Crimes Act 1961, s177.


The actus reus of culpable homicide is the killing of a human being by another human being, "directly or indirectly, by any means whatsoever".5 Whether culpable homicide is murder or manslaughter depends on whether the offender has one of the states of mind set out in s167 of the Crimes Act. The killing need not be intentional to be murder, but the mens rea requirement is not satisfied unless the killer knows that his or her actions are likely to cause death. All culpable homicides that are not murder are manslaughter.6

Our criminal law presupposes that the offender has normal mental and physical capacity: "[Ole principle of rational capacity is .. a precondition of one's eligibility for punishment."7 If a person is unable to understand the nature and purpose of the trial or to participate in the trial, he or she may be found to be "under disability". Where an accused is under disability, he or she cannot be tried and will, instead, be detained as a patient.' For those who are fit to be tried but lacked capacity at the time when the offence was committed, an insanity defence under s23 Crimes Act 1961 is available:

(2) No person shall be convicted of an offence by reason of an act done or omitted by him when labouring under natural imbecility or disease of the mind to such an extent as to render him incapable

(a) Of understanding the nature and quality of the act or omission; or
(a) Of knowing that the act or omission was morally wrong, having regard to the commonly accepted standards of right and wrong.

This is based on the M'Naghten rules.9 Its scope is limited and the burden of proving insanity lies on the defence to the standard of balance of probabilities.10 The emphasis is on cognitive defects. Irresistible impulse or personality defects such as psychopathy do not come within the defence. Success with the insanity defence results in a "Not Guilty

5 Crimes Act 1961, s158.

6 Crimes Act 1961, s171.

7 Simester, A & Brookbanks, W Principles of Criminal Law (1998) 254.

  1. This is governed by s108 Criminal Justice Act 1985. For a more detailed discussion see Simester & Brookbanks, supra at 7, 262.

9 [1843] EngR 875; (1843) 10 Cl & Fin 200.

10 Crimes Act 1961, s23(1), R v Cottle [1958] NZPoliceLawRp 16; [1958] NZLR 999.

By Reason of Insanity" verdict. There is a range of dispositional options: detention as a "special patient" is the most usual outcome but there is also provision for detention in hospital as a patient (this allows for out-patient treatment), immediate discharge or no order at all where the offender is already a prisoner."

If a person kills in reasonable self-defence, she has not committed an offence at all and will be acquitted. Self-defence is governed by s48 of the Crimes Act 1961, as amended in 1980: "Everyone is justified in using, in defence of himself or another, such force as, in the circumstances as he believes them to be, it is reasonable to use." This is a mixed subjective and objective test. A person who wrongly believes she is being threatened with a gun is entitled to use what force would be reasonable if she was being threatened with a gun; but if she fails to take advantage of an available escape route, the defence may well fail because her use of force against the (imaginary) threat was unreasonable.12

Provocation reduces murder to manslaughter." It is defined in s169 of the Crimes Act 1961. It requires that, as a result of provoking words or conduct, the offender has suffered a loss of self-control that has induced him or her to commit the homicide, and that the provocation was severe enough that it would be sufficient to deprive a person with ordinary powers of self-control of that self-control. In applying this test, certain personal characteristics of the offender that increase or

explain the provocativeness of the conduct can be taken into account.

Where any of these defences fail, or where there is no defence, and the actus reus and mens rea are proved beyond reasonable doubt, the offender will receive the mandatory penalty of life imprisonment. It is only in "exceptional" cases that a person sentenced to life imprisonment will be released on parole in under ten years.14

  1. Criminal Justice Act 1985 s115. For more detailed description see Simester & Brookbanks, supra n 7, 296-297.
  2. For a more detailed discussion of the elements of self-defence, see Wright, F "The circumstances as she believed them to be: a reappraisal of s48 of the Crimes Act 1961" [1998] Waikato Law Review (forthcoming).

13 With lesser offences, provocation will be a mitigating factor.

14 Criminal Justice Act 1985, s80.


The English version of the diminished responsibility defence was created by s2(1) of the Homicide Act 1957. Section 2(1) states:

(1) Where a person kills or is party to the killing of another, he shall not be convicted of murder if he was suffering from such abnormality of mind (whether arising from a condition of arrested or retarded development of mind or any inherent causes or induced by disease or injury) as substantially impaired his mental responsibility for his acts or omissions in doing or being a party

to the killing;

Diminished responsibility, like provocation, reduces murder to manslaughter15 It is a defence only to murder.

The defence as enacted in both England and most of the Australian jurisdictions has three elements: that the accused was suffering from an abnormality of mind, that the abnormality of mind arose from one of the stated causes, and that it substantially impaired the accused's mental responsibility for the killing. There are no major differences of interpretation of the defence in the jurisdictions where it has been enacted, and the discussion below draws from both English and Australian case-law and reports.16

According to one of the earliest English decisions on diminished responsibility, an abnormality of mind is a "state of mind so different from that of ordinary human beings that the reasonable man would term it abnormal"." Judges have been reluctant to be more precise, but a New South Wales study found that the defence had been used where there had been diagnoses of psychosis, organic brain disorder, schizophrenia, epilepsy, hypoglycaemia, depression (reactive and endogenous), post-traumatic stress disorder, chronic anxiety and personality disorders.18

  1. Diminished responsibility should be distinguished from diminished capacity, which is a claim that the offender's mental state prevented him or her from forming the state of mind required by the definition of the offence. See Aranella, P "The Diminished Capacity and Diminished Responsibility Defenses: Two Children of a Doomed Marriage" (1977) 88 Columbia LR 827, 828-829. Diminished capacity could, in theory, operate in New Zealand without the need for legislative approval.
  2. Although the structure of the defence in New South Wales is now different (see text above n71), this discussion makes use of case-law on the previous provision and research into the operation of this provision.

17 R v Byrne [1960] 1 QB 396.

  1. NSWLRC Discussion Paper 31 - Provocation, Diminished Responsibility and Infanticide (1993).

The etiology of the abnormality of mind is important because only some abnormalities of mind are covered by the defence. However, a study of the defence as it operated in England found that medical reports were frequently silent as to the cause of the illness. The main function of this requirement seems to be that it allows the exclusion of those who kill while intoxicated or who are merely angry or jealous.19 This may explain the tolerant approach: the instances where etiology is of genuine importance are easily identified even by non-experts.

The impairment of responsibility is not a medical concept but a legal or moral one. For this reason, it ought to be a question for the jury: "[i]t involves a value judgment by the jury representing the community (or by a judge if there is no jury), not a finding of medical fact."" However, in practice, decisions about diminished responsibility are frequently made without the assistance of a jury. English courts have stated clearly that defendants are entitled to plead guilty to manslaughter on the grounds of diminished responsibility.21 This only happens if the prosecution is satisfied that the defence is made out, but the result is that the decision is made by the judge. Guilty pleas are not unusual. Dell looks at a sample of 256 men convicted of manslaughter on the basis of diminished responsibility in England and Wales between 1966 and 1977; 90% of these cases were dealt with by way of a guilty plea. She also looked at a sample that included those whose diminished responsibility defence had failed. In 1976 and 1977, the defence was raised in 194 homicide cases. Del found that the prosecution or court was prepared to accept a guilty plea in 85% of these, although some of these went to trial for other reasons.22

A more recent study from New South Wales produced similar results. Between 1990 and 1993, 36 offenders relied on diminished responsibility: the defence had an acceptance rate of 61.1%. Only nineteen of these cases resulted in a jury trial. Of the other seventeen cases, five cases were tried by judge alone (this is not an option under English law) and the rest of the cases must have been dealt with by

19 Ibid, 47-49.

20 R v Trotter (1993) 35 NSWLR 428, 431 per Hunt CJ.

21 Vinagre (1979) 69 Cr App R 104.

22 Dell, S Murder Into Manslaughter (1983) 25-26.

way of guilty plea." Therefore, although the exact proportion of trials to guilty pleas varied between the two jurisdictions, it is clear that a significant number of outcomes were decided without the benefit of a jury.

The maximum sentence for manslaughter in the jurisdictions that have a diminished responsibility defence is life imprisonment. Not all those convicted of manslaughter on the basis of diminished responsibility receive custodial sentences, but a high proportion of those convicted are imprisoned rather than being hospitalized or receiving noncustodial sentences. English studies show fluctuations in sentencing practices. McKay concludes that "an accused who used diminished responsibility successfully had an almost even chance of being sent to prison".24 A random sample of five sentencing appeals revealed sentences varying from 3 years probation to 7 years imprisonment.25 Life sentences are not unknown.26


There has never been a diminished responsibility defence in New Zealand although it has been proposed at least twice.

In 1879 the Criminal Code Bill Commission's Report on the Law Relating to Indictable Offences suggested that punishment should be mitigated where an offender, although not insane, was not wholly responsible because of weakened or disordered intellect, but this was not acted on.27 The 1960 Crimes Bill included a diminished

  1. Griffith, G and Figgis, H, NSW Parliamentary Library Research Service, Crimes Amendment (Diminished Responsibility) Bill 1997: Commentary and Background (1997) 10.

24 McKay, RD Mental Condition Defences in the Criminal Law (1995) 183.

  1. Lewis (1989) 11 Cr App R (S) 577 - 12 months reduced to 3 years probation, mother killed newborn baby while depressed; Chiu Au-Yeung (1989) 11 Cr App R (S) - 15 years reduced to 6, chef attacked assistant cook and manageress for no apparent reason, described as `over-controlled'; Smith (1988) 10 Cr App R (S) 120 - 3 years imprisonment upheld , severely depressed wife killed estranged husband; Yeomans (1988)10 CrApp R (S) 63 - 8 years reduced to 5, separated from wife, had inadequate personality, severe depression, tried to kill wife and drowned daughter in the sea; Woollaston (1986) 8 Cr App R (S) 360 - killed girlfriend's former partner who had been making threats, was either depressed as result of emotional injury and trauma or suffering from paranoia.

26 Byrne, supra n 17, is an example of a case where the accused received a life sentence.

27 Brookbanks (1984), supra at note 3, 30.

responsibility defence, to apply where the "jury are satisfied that at the time of the offence the person charged, though not insane, was suffering from a defect, disorder, or infirmity of mind to such an extent that he should not be held fully responsible".28 The outcome was detention at Her Majesty's Pleasure, rather than a manslaughter verdict. The provision did not find its way into the 1961 Act. This is probably because the main impetus for the new defence was concern that mentally ill offenders should not be executed. Since the 1961 Act abolished the death penalty, that possibility was removed and there was no apparent need for an additional defence.

Part of the gap left by the lack of a diminished responsibility defence has been filled by the defence of provocation: some conditions that would satisfy the mental abnormality requirement for diminished responsibility are capable of being "characteristics" for the purposes of provocation, providing a means of reducing murder to manslaughter where the offender suffers from a mental abnormality. Initially, "characteristics" was read narrowly in order to avoid any overlap with diminished responsibility: "it is not enough to constitute a characteristic that the offender should merely in some general way be mentally deficient or weak-minded. To allow this to be said would ... deny any real operation to the reference made in the section to the ordinary man, and it would, moreover, go far towards the admission of a defence of diminished responsibility without any statutory authority in this country to sanction it."29 However, more recently, the Court of Appeal has suggested that an overlap of some kind "may be seen as the inevitable and deliberate effect of the changes embodied in s169 of the Crimes Act 1961.'30 However, if the sole effect of the abnormality is to reduce the offender's powers of self-control, the "characteristic" will not be taken into account. For this reason, provocation is only a partial replacement for diminished responsibility.

Commentators have repeatedly criticised the insanity defence. It reflects a nineteenth century view of mental illness, and many serious mental disorders do not satisfy the test in s23. There is little doubt that it is obsolete and misleading. It reflects the view that those whose conduct stems from mental disorder should not be punished but it

28 [bid, 30.

29 [1962] NZPoliceLawRp 13; [1962] NZLR 1069.

30 R v McCarthy [1992] 2 NZLR 550, 558.

fails to protect from punishment many grossly impaired offenders. The disposition of those found not guilty by reason of insanity is also problematic. From the point of view of public safety, there are concerns that medical disposition does not adequately protect the community from dangerous but insane offenders. The victim's family, an insanity verdict may feel that the crime remains unavenged: the insane offender committed the crime but is not "guilty" and is not punished. From the point of view of the offender, the stigma of being "found insane" and the possibility of hospitalization rather than a determinate sentence may persuade an offender to plead guilty. This is not satisfactory either, since it results in the punishment of some who ought not to be punished.

The mandatory life sentence does not allow judges to reflect degrees of culpability. A person who killed while seriously depressed receives the same sentence as the person who kills in the course of an armed robbery. Parole may be available sooner for some than for others but the usual minimum of 10 years applies to all. Another danger of inflexible sentencing is that it may lead to jury nullification or the use of discretion to ensure a murder charge is not brought in the first place.

Those who propose a diminished responsibility defence for New Zealand do so because of its ability to resolve these distinct but related problems. It would provide greater flexibility and allow the inadequacies of current law to be overcome:3'

[D]iminished responsibility represents a useful addition to the courts' means of disposing of mentally disordered offenders. Furthermore it is able to accommodate useful developments in modern forensic psychiatry, and to embrace "just about all types of pathological mental abnormality" without sacrificing the notion of responsibility in the criminal law.

Three recent cases can be used to highlight this perceived inadequacy. The first is R v Campbell32 Campbell killed a man whom he thought was making a homosexual advance towards him. He was depressed and had symptoms of post-traumatic stress disorder, in part because of childhood sexual abuse. When the deceased touched him, he had a flashback and reacted to the recalled conduct of his original abuser. The insanity defence was of no assistance, because Campbell was

31 Brookbanks, supra n 3, 29-30. See also Ablett Kerr, supra n 3, at 4.

32 (1997) 15 CRNZ 138, 142.

aware of the nature and quality of his acts and that they were morally wrong."

Campbell was eventually convicted of manslaughter, relying on the defence of provocation but this can be seen as an undesirable stretching of that defence.34 Campbell was lucky because he met the requirements for provocation but diminished responsibility would provide more accurate labelling of his actions.

Another case where there was evidence that might well have supported diminished responsibility was Gordon. June Gordon was convicted of the murder of her husband. (The actual killing was carried out by a friend.) She was suffering from severe depression. There was psychiatric evidence that she had not really intended to have her husband killed and had been in a fantasy state. The trial judge ruled this evidence was not admissible. She may have had impaired judgment but this was not inconsistent with an intent to kill, so it would not assist her defence in any way.35 Mrs Gordon's appeal from a murder conviction was dismissed despite the availability of new psychiatric evidence. It "could not in our view have led the jury to doubt the conclusion they reached, that the whole of the evidence - not simply the appellant's statements to her friends before the shooting, but her taped discussions with Taylor, her actions in the car, and what she said later - disclosed the desire and intention that Taylor kill her husband."36 Why she formed the desire was irrelevant. Gordon's life sentence was confirmed. In disposing of the appeal, the Court of Appeal acknowledged that "[w]ere a defence of diminished responsibility available in this country, it might well have been availed of here But sympathy for the defendant cannot prevail over the current statutory provisions ."37

A final case that some commentators have suggested would have been better treated as one of diminished responsibility is R v Oakes." Gay Oakes was charged with the murder of her partner, Doug Gardner. After years of severe abuse, and fearing another attack, she put a fatal

  1. This was established by his conduct after the event: initially, he went to some trouble to conceal his involvement.

34 Ablett Kerr, supra n 3, 8.

35 R v Gordon (1993) 10 CRNZ 430, 437.

36 Ibid, 439.

37 Ibid, 441.

38 [1995) 2 NZLR 673.

dose of drugs into his coffee. Gardner died some hours later but instead of contacting the police, Oakes (assisted by another) buried his body in the garden. It was not found for a year. Her main defence was self-defence, supported by evidence about the effect of long-term abuse. The implication was that the effect of the abuse on Oakes' mental state caused her to mistakenly believe she was under threat and that it was necessary to kill Gardner. "[H]er sense of judgment, her ability to reason rationally, will be impaired. Her sense of vulnerability will be increased, any threat will be magnified, affecting her ability to reason in terms of how dangerous her situation really is."39 However, the jury rejected the self-defence claim Oakes' appeals to the Court of Appeal and the Privy Council failed: the jury had not been misdirected and "there was evidence, which the jury were entitled to accept, pointing to this not being a desperate reaction to a perceived, albeit distortedly so, threat of pending danger, but rather a deliberate and calculated crime" 40

Ablett Kerr's view is that the law of self-defence should be able to accommodate the abused woman who kills but that is "no longer convinced that on a practical level it is going to do so".41 Rather than arguing that the woman genuinely believed it was necessary to kill, that her story is plausible because mental impairment caused by the abuse made such the mistake understandable, and that on her view of the circumstances the danger was severe enough to justify homicide, it would be more effective to focus directly on the mental impairment. The woman killed because she was ill. Diminished responsibility, she suggests, would have a better chance of success in such cases.

If there was a diminished responsibility defence, the result in Campbell would have been the same - manslaughter - but it could have been achieved without 'stretching' the boundaries of provocation. Gordon and Oakes might not have ended in murder convictions. However, there are problems with importing the diminished responsibility defence, and these will be discussed next.

39 Ibid, 676.

40 Ibid, 683.

41 Ablett Kerr, supra n 3, 10.


The diminished responsibility defence is based on the assumption that mental abnormality can justify imposing a reduced penalty for homicide, despite the presence of intent or recklessness and the absence of legal insanity. Anthony Kenny questions this assumption and concludes that "the insanity defence should be the only way of avoiding conviction in a case where it is clear that the accused caused death with the relevant mens rea of intention or recklessness."42 Those who are not insane under the M'Naghten rules and who have mens rea for the offence in question should be convicted of murder and punished accordingly, although he allows that their disorder perhaps ought to be taken into account when calculating quantum of punishment. Any decision about whether hospital is more appropriate than prison should be made by the prison authorities post-sentencing.43

Kenny claims that the introduction of diminished responsibility has made it "easier for mentally ill killers to avoid the consequences of a murder conviction.' This is, however, only a negative consequence of the introduction of the defence if one first rejects the view that mental illness can reduce culpability. If it can and does reduce culpability, it would be imprisonment of mentally ill offenders that was the injustice, not their hospitalization. With respect, Kenny's argument assumes that responsibility is an all-or-nothing concept, but he does not provide a reason why it can not be diminished.

A contrary view is that the boundaries of criminal responsibility are determined by those who define and apply the law and, being socially and politically determined, they are fluid and apt to change. At different times in the history of criminal law, the mental requirements for particular offences have varied and the range of defences that are permitted has swelled and contracted. A case for diminished responsibility can be constructed without straying from conventional principles of criminal law.

  1. Kenny, Anthony "Can responsibility be diminished" in Frey, RG & Morris, Christopher W (eds) Liability and Responsibility (1991) 25.

43 Ibid, 25-26.

44 lbid, 30.

Through .the defence of insanity, there is provision for those who do not meet the requirements at all but rationality is not an absolute standard. This leaves a choice: will those whose rationality is compromised be treated exactly the same as those whose rationality is unquestionable? The defence of diminished responsibility reflects the view that they should not: "if rationality is a criterion for responsibility, then responsibility, too, should in theory be matter of degree which ranges along a continuum. Even if someone is not fully excusable, his or her rationality may be non-culpably compromised to a substantial extent, thus mitigating the deserved blame and punishment.... Ordinary morality makes differential, excusing allowances on a sliding scale of diminished rationality, and in principle the law might do so as well."45

The existence of a diminished responsibility defence is only a logical impossibility if there is only one coherent approach to criminal responsibility and this is not the case. There is nothing wrong in principle with reducing sentences to take mental illness into account. However, this does not mean that New Zealand should adopt the defence of diminished responsibility: questions about whether the way in which the defence is structured is satisfactory and about the consequences of its availability remain to be answered.

Almost from its conception, s2(1) of the Homicide Act 1957 (UK) has been the subject of criticism. One ground for criticism is the wording of the section itself. According to Griew,46

The phrase 'substantially impaired his mental responsibility for his acts in doing ... the killing' is, I believe, improperly elliptical. The word 'responsibility' serves a double function. Following `impaired ... mental' it suggests a condition of the defendant perhaps his capacity to comprehend and (so far as his 'mind' affects the matter) to conform to the requirements of the law. Preceding the phrase 'for his acts in doing ... the killing' it suggests the social consequences of that condition - an assessment of culpability and, in the context of a murder charge, the outcome of that assessment in a decision on the level of liability.... Parliament, it is submitted, has clumsily compacted two ideas those of reduced (impaired) capacity and of reduced (diminished)


  1. Morse, Stephen J "Diminished Capacity" in Shute, Sthephen, Gardner, John & Horder, Jeremy Action and Value in Criminal Law (1993) 249-50.

46 Griew, E "The future of diminished responsibility" [1988] Crim LR 75, 81.

Even if the move from impaired capacity to diminished liability is a legitimate one, as was argued above, the language with which this move is described is unnecessarily difficult. The "abnormality of mind" requirement is difficult because of the limit to permissible abnormalities in terms of their etiology. Yet the terminology is the creation of lawyers and bears no relationship to psychiatric categories. Different psychiatrists interpret the requirements differently, leading to inconsistency and unpredictability in the use of the defence."

These difficulties of interpretation have two practical consequences. The first is that the "substantial impairment" test magnifies the role of the expert witnesses and the second is that there is ample room for subversion of the strict words of the section in order to achieve a `merciful' result in individual cases.

Anthony Kenny argues that the drafting of s2(1) turns what should be a question for the jury into a question for an expert witness:48

In practice 'mental responsibility' has come to mean something very close to 'a mental state such that psychiatrists believe he ought to be convicted'. ...The question whether an individual should be convicted should be a question, not for the psychiatrists, but for the jury; the question whether persons of a certain kind should be punished is a question for the psychiatrists but for the


New Zealand courts have been cautious about allowing experts to usurp the jury's role;" it is arguable that the structure of the diminished responsibility defence leaves the expert with no alternative but to do this. Griew comments that "[p]sychiatrists ... are continually asked ... whether in their opinion the mental responsibility of defendants was substantially impaired. Judges allow the question to be asked and often themselves press for an answer."" The role of the experts is enhanced by the frequency with which offenders plead guilty; in such cases, effectively, it is the experts who determine whether responsibility was diminished.

47 Ibid, 78.

48 Kenny, Anthony The Ivory Tower (1985) 54.

  1. See, for instance, R v CS (1993) 11 CRNZ 45, where expert evidence was rejected because of concerns it was simply an assertion of the truthfulness of the (child) witness.

50 Griew, supra n 46, 83.

The ambiguous words of the section have allowed some "creative" uses of the defence. Ashworth comments that "judges, counsel, doctors, and juries have approached it with a compassionate pragmatism rather than with ... rarified verbal analysis ...".51 Griew admits that "Mt is...doubtful whether all decisions turning on the section can plausibly be explained as guided by a careful reading of its language; there must be many cases in which the section is rather to be seen as legitimising an expression of the decision- maker's personal sense of the proper boundary between murder and manslaughter."52

An example of this is mercy killing, which falls squarely within the definition of murder since it is, almost by definition, intentional killing. Dell stated that 10 of 260 diminished responsibility cases in her study were mercy killings of seriously ill relatives, mostly by men in their 60s or 70s.53 In all these cases, a depressive illness was diagnosed. "However, there were cases where the doctors were unable to find any signs of disorder in such defendants but where they nevertheless unanimously reported that they inferred from the circumstances that abnormality must have been present at the time of the offence."54 The conclusion that that pressure caused an illness is convenient, since it allows mitigation, but it seems sometimes to be fictitious.

For the individuals concerned, this might seem to be a merciful application of the law but it is not a feature of the defence that should commend it. The problem is that only some will benefit from this nullification of the strict words of the defence, there is an unacceptable element of chance. Griew comments that "psychiatrists have varied in the extent of their willingness to use the section creatively, without undue regard for its terms or fortified by an appreciation of their obscurity. Some, indeed, have been less aware than others of the section's potential for flexible reading ... There can be little doubt that the fate of some people charged with murder since 1957 has turned on the qualities of robustness and sophistication shown by those professionally involved in their cases."" In England, where the ambiguous wording is something that professionals have to work with,

51 Ashworth, A Principles of Criminal Law (2nd edn, 1995) 277.

52 Griew, supra n 46, 78.

53 Dell, supra n 22, 35.

  1. Ibid, 30. Emphasis added. See also Otlowski, M "Mercy Killings in the Australian Criminal Justice System" (1993) 17 Crim LJ 10.

55 Griew, supra n 46, 79.

this is probably the best outcome; to consciously adopt a defence that operates in this way is another matter altogether.

Some doubts might also be expressed about the way in which the defence is limited to murder and its construction as formal mitigation. If it is no more than mitigation of penalty, why does the label change from murder to manslaughter? But if there is more to it than a simple reduction of penalty, why is this option not available for other offences? A jury faced with an abnormal offender charged with other offences could make use of the opportunity to express their conclusion that responsibility was impaired just as they do with murder. The answer that it is not necessary because there is discretion in sentencing for all other offences does not allow for the jury's role or for the importance of labels.

The pragmatic approach to diminished responsibility that emerges from the case law does require a mental abnormality upon which to hang the defence and this leads to a further problem, that of unnecessary medicalization of women's offending.

Feminist criminal lawyers and criminologists have documented a tendency for medicalization of women's offending. Heidensohn describes early research into women's offending: "[m]uch of the `prehistoric' work on women ... stressed the irrational nature of their actions. Their behaviour was determined by their physiology or their instincts."" Schneider and Jordan complain that "[t]he traditional view of women who commit violent crimes is that their action was irrational or insane. Consequently, an impaired mental state defence has often been relied on automatically."" Legal advisers may even have actively dissuaded women from putting forward other defences." There is some evidence to support these assertions.

A 1982 Australian study looked at sixteen women convicted of killing their partners or found not guilty by reason of insanity, comparing the

  1. Heidensohn, F "Gender and Crime" in Maguire, M Morgan, R and Reiner, R (eds) The Oxford Handbook of Criminology (1st edn, 1994) 1014.
  2. Schneider E & Jordan, S with Agueras, C "Representation of Women Who Defend Themselves in Response to Physical or Sexual Assault", 4 National Journal of Criminal Defence 141, 144.
  3. Gillespie, C Justifiable Homicide: Battered Women, Self-Defence and the Law (1989) 25-27.

women's account of events with the court transcripts." In thirteen of the cases, if the women's accounts were believed, the partner's violence was the direct and immediate reason for the homicide.60° However, of the 13 substantive defences raised in these 16 cases, self-defence was argued twice; provocation° five times; and defences of mental impairment six times.62

The authors suggested that this was symptomatic of attitudes towards women within psychiatry.63

In much classic psychiatry, which both mirrors and perpetuates everyday views about women, it is not acceptable for women to be angry or aggressive, and a woman who displays signs of being such is, by definition, sick. In addition, women are commonly seen, not as rational and responsible beings, but as being irrational and unable to cope.

Diminished responsibility therefore reinforces existing stereotypes of women offenders. A study of the way women were portrayed in sentencing reports provides further support for this assertion. Allen found that "an average of 20 per cent of the total length of reports on female offenders is occupied by statements which in some way refer to the subject's psychology. This is in sharp contrast to reports on male offenders, which instead tend to focus on the more external and material aspects of the offender's behaviour, biography and life-style."64

One reason for proposing diminished responsibility as a defence in New Zealand is that it reduces the likelihood that a woman who kills an abusive partner will be convicted of murder. This is why Ablett Kerr gives the case of Oakes as an example of one where diminished responsibility would have been helpful.° Medical excuses are more likely to succeed than full justifications like self-defence or partial

  1. Bacon, W and Lansdowne, R "Women who kill husbands: the battered wife on trial" in O'Donnell, C and Craney, J (eds) Family Violence in Australia (1982).

60 Ibid, 89-90.

  1. In the cases argued as provocation, the provocative conduct was an assault or threat to kill but self-defence was not offered as an alternative.

62 Bacon & Lansdowne, supra n 59, 89.

63 Ibid, 90.

  1. Allen, H "Rendering Them Harmless: The Professional Portrayal of Women Charged With Serious Violent Crimes" in Carlen, P and Worral, A (eds) Gender, Crime and Justice (1987) 83.

65 Supra n 38.

justifications like provocation. But using diminished responsibility shifts the focus from the violence to the woman's own "weakness". It may even result in another, possibly more advantageous, defence being ignored. This danger of "over-pleading" is enhanced because of the ability to plead guilty on the basis of diminished responsibility and avoid the trauma and uncertainty of a trial.

Proof of this occurring is not easily found, since the summaries of facts in appellate decisions do not necessarily cast light on the credibility of an appellant's version of the facts, but there are certainly examples where another defence was at least arguable. In the case of R v Ahluwalia66 the main defence was provocation; a retrial was granted on the basis that diminished responsibility had not been put to the jury; the appellant later pleaded guilty to manslaughter on the basis of diminished responsibility, effectively abandoning the provocation defence. A comment on the case states: "[diminished responsibility ... is more obviously an admission of mental abnormality. Holding it out as the most promising defence for battered women forces them to choose between being labeled as bad or partially mad. Many defendants ... might not care as much about their categorisation as about their liberty. But some will undoubtedly perceive it to be deeply insulting to be told that, unless they accept a label of psychological abnormality, they run the risk of escaping the prison of domestic violence only to spend a long time in a less metaphorical prison."67

A case in which diminished responsibility succeeded but self-defence appears arguable is Woollaston." The deceased was the previous partner of Woollaston's lover. The deceased was known to be violent and had made threats directed at Woollaston. He became very scared, refused to leave the house and increased his home security. When he saw the deceased approaching the house, Woollaston thought he had come to carry out the threat and shot him. On the surface this looks more like a self-defence case than a case of diminished responsibility but Woollaston was found to have a 'mental abnormality'. According to one expert he was suffering from a phobic anxiety state with paranoia, that he was scared and unable to cope with provocation.

66 [1992] EWCA Crim 1; [1992] 4 All ER 889.

67 Ibid, 737,

68 (1986) 8 Cr App R 360.

Another said that he was depressed as the result of a real and apparent threat to his life which resulted in acute feelings of fear and terror. Without expressing an opinion about whether Woollaston's use of force was reasonable, this description of why he killed the deceased appears to deny the reality of the threat he was facing and avoids the fact he acted for a reason that is, within limits of reasonableness, lawful. Instead, he is 're-created' as an abnormal actor.

There is, obviously, a clash between the immediate interests of the offender, for whom the lightest possible sentence is likely to be the most important objective, and the interests of women in general, for whom an assumption of madness rather than badness is, since often untrue, demeaning. However, when there might be better alternatives, the adoption of a new defence that has this side-effect, is not a desirable reform.


It is undeniable that the current law is capable of producing injustice but this should not be overstated. Brookbanks states that the apparent narrowness of the insanity defence is mitigated by a generous interpretation of s23:69

[B]ecause the M'Naghten Rules are very narrowly formulated, it is not uncommon for judges to interpret them liberally in order to accommodate difficult but deserving cases.

The provocation defence is also used generously. There are jury decisions that are hard to explain in terms of the words of s169 of the Crimes Act, such as Campbell, where it is difficult to see how the characteristic of suffering from post-traumatic stress disorder had an effect other than reducing the accused's powers of self-control. Nonetheless, when a murder conviction is unavoidable, the courts have no choice but to impose the life sentence.

Despite these shortcomings of the current law, it is submitted that diminished responsibility based on the English model is not the solution. This is not because responsibility cannot be diminished. On the contrary, it is accepted that mental illness is capable of reducing

69 Simester & Brookbanks, supra n 7, 268.

culpability and that there is no reason in principle why this should not be recognised through the device of formal mitigation. The problems that lead to the conclusion that diminished responsibility is an undesirable addition to the Crimes Act 1961 are two-fold.

First of all, the defence created by s2(1) of the Homicide Act is structurally flawed. Attempts to improve s2(1) have been unsuccessful - the Butler Committee recommended major changes in 1975 but this was never implemented.70° The flaws can be circumvented by a generous interpretation. However, it should be a goal of the reform process to avoid the need to circumvent flawed defences by replacing them with defences that are better constructed. The introduction of a new defence that has been widely criticised would be perverse.

The response to this might be that the defence could be introduced in a modified form: there is no obligation to follow the English wording. New South Wales made major changes to the defence in 1997, incorporating (inter alia) a more detailed explanation of the effect that the abnormality of mind should have:71

(1) A person who would otherwise be guilty of murder is not to be convicted of murder if:

(a) at the time of the acts or omissions causing the death concerned, the person's capacity to understand events, or to judge whether the person's actions were right or wrong, or to control himself or herself, was substantially impaired by an abnormality of mind arising from an underlying condition, and
(a) the impairment was so substantial as to warrant liability for murder being reduced to manslaughter.

(2) For the purposes of subsection (1)(b), evidence of an opinion that an impairment was so substantial as to warrant liability for murder being reduced to manslaughter is not admissible.

"Underlying condition" is defined in s23A(8) as "a pre-existing mental or physiological condition, other than a condition of a transitory kind."

The revised New South Wales defence does dispose of some objections to the English wording, and the changes clarify the respective roles of

  1. Report of the Committee on Mentally Abnormal Offenders (chairman, Lord Butler) Cmnd 6244 (1975).
  2. New South Wales Crimes Amendment (Diminished Responsibility) Act 1997, amending s23A Crimes Act 1900.

expert witnesses and jurors. However, the problem of unpredictability remains. If the older formulation places too much emphasis on the expert's view, this alternative formulation may give too much leeway to the jury, which could ignore the opinions of experts with impunity. It is difficult to see how the definition of 'underlying condition' is an improvement on 'mental abnormality', and its precise definition would still depend on the experts applying it. Medicalization and over-pleading would be as likely with these versions of the defence as with the existing version.

In any event, not all who fall between the cracks of the current law of homicide are mentally ill. The potential for injustice arising out of the mandatory sentence is not restricted to those who suffer from a mental abnormality - an example might be a person who killed under compulsion but could not claim a defence under s24 of the Crimes Act 1961 because murder is an excluded offence under s24(2). While it might be possible to construct a mental abnormality in order to bring such a person within diminished responsibility, it would be more honest to acknowledge that the reason the murder conviction and especially the life sentence seems unjust is the existence of the compulsion, not the immediate but transient state of depression that it caused.

What is really needed is a several-pronged attack on the law of homicide, with attention paid to the mandatory penalty, to the mens rea for murder - are all intentional killings really in the 'worst' category of homicide? - and to the definition of several defences, including but not limited to insanity. If these other changes were made, there might well be room for a diminished responsibility defence, but to introduce it by itself would be harmful to some offenders and might, ironically, delay other reform. In England, the availability of diminished responsibility may have put pressure on the legally insane to use it instead of insanity. McKay found that in the UK there were on average about six special verdicts a year but it seems implausible that only six seriously mentally ill people were charged with criminal offences. What seems more likely is that other offenders used diminished responsibility or (if the offence was one with discretionary sentencing) pleaded guilty and hoped to have mitigation of their sentence.72 Rather

72 McKay, supra n 24, 143.

than supplementing insanity, diminished responsibility appears to have replaced it. This makes it even less likely the defence will be reformed. Yet the problems with insanity remain, and a new problem has emerged for those who accept the easier option of relying on diminished responsibility. If it is correct that those who are truly insane are not responsible for their actions, a manslaughter conviction is an objectionable outcome even when the disposition is medical rather than a prison term.

NZLII: Copyright Policy | Disclaimers | Privacy Policy | Feedback