Diminished responsibility

In criminal law, diminished responsibility (or diminished capacity) is a potential defense by excuse by which defendants argue that although they broke the law, they should not be held criminally liable for doing so, as their mental functions were "diminished" or impaired. It is not universally accepted, e.g. in the Republic of Ireland the Irish Supreme Court rejected the defense in The People (DPP) v Joseph O' Mahony (1984) ILRM 244.

Discussion

This is an aspect of a more general insanity defense (see the M'Naghten Rules). Peter Arenella, in the Columbia Law Review (1977 p.830), stated, "the defense [of diminished responsibility]...was first recognized by Scottish common law to reduce the punishment of the 'partially insane'." It developed from the practice of juries in the 19th century of returning verdicts of guilty with a recommendation as to mercy or mitigation of sentence to reflect any extenuating circumstances. In a series of decisions, given mainly by Lord Deas, a doctrine grew that various types of mental weakness could have the effect of reducing what would otherwise be a conviction for murder (which attracted capital punishment) to one for culpable homicide (where the courts had greater discretion in sentencing). An example of a "diminished capacity" might be extremely low intelligence. The rationale of the defense is that, as a precondition to punishment, the criminal law requires conduct to be voluntary. If something interferes with the capacity of the individual to choose to break the law, this should be reflected by an excuse or exculpation. Thus, if an individual has the physical age of twenty years, but the intellectual age of five years, the law should balance the need to be fair to the individual but equally offer some protection to society from a person who may not have complete control over their behavior.

The effect of the defense varies between the jurisdictions. In some, it will result in full excuse and therefore produce a verdict of "not guilty". In others, it offers only exculpation to a degree, resulting in the substitution of a lesser offence (e.g., manslaughter instead of murder) or a mitigated sentence.

The California Penal Code states (2002), "The defense of diminished capacity is hereby abolished ... there shall be no defense of diminished capacity, diminished responsibility, or irresistible impulse..."

English law

Diminished responsibility operates only as a mitigatory defence to reduce what would otherwise have been murder to manslaughter (termed "voluntary" manslaughter for these purposes). This allows the judge sentencing discretion, e.g. to impose a hospital order under s37 Mental Health Act 1983 to ensure treatment rather than punishment in appropriate cases. Thus, when the actus reus (Latin for "guilty act") of death is accompanied by an objective or constructive version of mens rea, the subjective evidence that the defendant did intend to kill or cause grievous bodily harm because of a mental incapacity will partially excuse his conduct. The burden of proof is on the defendant to the balance of probabilities.

s2(1) of the Homicide Act 1957 states:

Where a person kills or is party to a 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 and omissions in doing or being a party to the killing.

Components

Abnormality of mind

The defence potentially includes a wide range of mental disorders, provided that the disorder results from:

• a condition of arrested or retarded development;
• any inherent causes; or
• disease or injury.

Thus, the scope is wider than a medical definition of mental illness because the M'Naghten Rules only apply to mental conditions which affect the accused’s cognitive processes to such an extent that the person does not know the nature or quality of his or her act, or does not know that that act was wrong. Whereas diminished responsibility requires a substantial impairment caused by an abnormality of mind which may cover not only abnormalities of perception or cognition, but also an abnormality affecting the ability to exercise will power, and extreme emotional states falling outside the medical definitions of illness and abnormality. Although the effects of voluntarily consuming alcohol or drugs are excluded, it does cover diseases such as delirium tremens caused by long-term alcoholism or drug-taking if the resulting condition causes an impairment of judgment and emotional responses, or the drinking or drug taking becomes involuntary (see R v Tandy (1988) 1 AER 267). In R v Byrne (1960) 2 QB 396 the defendant was a sexual psychopath who strangled a young woman and mutilated her body. Lord Parker CJ defined abnormality of mind as

a state of mind so different from that of ordinary human beings that a reasonable man would term it abnormal. It appears...to be wide enough to cover the mind’s activities in all its aspects, not only the perception of physical acts and matters, and the ability to form a rational judgment as to whether an act is right or wrong, but also the ability to exercise will-power to control physical acts in accordance with that rational judgment.

Whether a defendant is suffering from an "abnormality of mind" is a question for the jury having heard the medical evidence and all the evidence including the defendant's acts or statements. Hence, it has been pleaded with success in cases involving mercy killings, deserted spouses or disappointed lovers who kill while in a state of depression (once referred to as the "Hamlet syndrome"), reactive depressions, chronic anxiety states, alcoholism, women suffering from "pre-menstrual syndrome", and "battered wife syndrome" so long as the condition is verified as "real" by medical experts.

R v Shickle (2005) EWCA Crim 1881 the defendant stabbed a diabetic several times with syringes full of insulin. The defence denied that excess insulin was the cause of death and adduced evidence that insulin, even in excess, is not a toxic substance which causes death. Further, although Shickle could not remember having injected the deceased, it was possible that she had done so under the impression that he needed insulin and that she had, in her confused state, administered an overdose. Because these explanations were not consistent with a plea of diminished responsibility, the defence was not raised. Two later psychiatric examinations claimed that she suffered from a severe emotionally unstable personality disorder that prevented her from admitting the facts necessary to substantiate diminished responsibility. Reviewing the authorities on whether to accept fresh evidence to support a plea that was not advanced at the trial, the Court of Appeal noted that in R v Ahluwalia (1993) 96 Cr. App. R .133 Lord Taylor observed that:

If there is no evidence to support diminished responsibility at the time of the trial, this court would view any wholly retrospective medical evidence obtained long after the trial with considerable scepticism.

The effect of the abnormality

The abnormality of mind must substantially impair, but need not totally impair, the defendant's mental responsibility. As in Byrne, the defendant may understand the nature and quality of what he is doing, and/or know that it is wrong, and may have some degree of control over himself. In R v Egan (1992) 4 AER 470, it was held that "substantial" impairment was the kind of word that could be interpreted in a broad common sense way. Hence, it meant that there was:

...more than some trivial degree of impairment which does not make any appreciable difference to a person's ability to control himself, but it means less than total impairment.

The relationship to drunkenness and drug taking

Drunkenness cannot be a defence to manslaughter or any other crime of basic intent, and the fact that a defendant might have been drunk at the time of committing a murder is also irrelevant to support a plea of diminished responsibility because it is an "external" not an "inherent cause" within s2. In R v Gittens (1984) QB 698 a defendant who suffered from depression killed his wife and stepdaughter after drinking and taking drugs for medication. The direction to a jury facing both diminished responsibility and drunkenness should be:

• Would the defendant have killed as he did if he had not been drunk?

and if the answer to that is yes,

• Was he suffering from diminished responsibility when he did so?

The more chronic forms of alcoholism and the long-term use of heroine and cocaine (see R v Sanderson (1994) 98 Cr. App. R. 325) can become a relevant factor where a craving for drink or drugs causes an abnormality of mind. This must be distinguished from the situation in which the abnormality of mind causes a craving for drink or drugs . R v Tandy (1989) 1 AER 267 held that where a defendant could show that she was suffering from an abnormality of the mind, that it was induced by disease (namely alcoholism), and that it substantially impaired her responsibility for her actions, then the defence of diminished responsibility would be made out. In the actual case, the craving for alcohol did not render the use of alcohol involuntary. The defendant was in control when she began drinking, and the state of mind in which she killed her daughter was merely induced by the alcohol. In R v Dietschmann (2003) UKHL 10, the House of Lords held that where a defendant suffers from an abnormality of mind within s2(1) also consumes alcohol before the killing, the jury should find him or her guilty of manslaughter if they are satisfied that, notwithstanding the alcohol consumed and its effect, the abnormality of mind substantially impaired the mental responsibility for the fatal acts. The sub-section does not require the abnormality of mind to be the sole cause of the defendant’s acts; even if the defendant would not have killed if he had not consumed alcohol, the causative effect of the alcohol does not prevent an abnormality of mind suffered by the defendant from substantially impairing his mental responsibility for the fatal acts.

Scottish law

During the course of the 20th century the courts began to limit the mental conditions falling within diminished responsibility. In HM Advocate v Savage (1923) JC 49 Lord Alness addressed the jury (at 51):

It is very difficult to it put in a phrase, but it has been put in this way: that there must be aberration or weakness of mind; that there must be some form of mental unsoundness; that there must be a state of mind which is bordering on, though not amounting to, insanity; that there must be a mind so affected that responsibility is diminished from full responsibility to partial responsibility. In other words, the prisoner in question must be only partially accountable for his actions. And I think one can see running through the cases that there is implied ... that there must be

some form of mental disease. This statement became the authoritative version of the test for diminished responsibility and the various factors mentioned by Lord Alness were regarded as being cumulative in nature. The effect was that the test became difficult to satisfy, and the courts adopted the position that the scope of the plea was not to be further widened (e.g. Carraher v HM Advocate (1946) JC 108 held that the plea was not available to a person suffering from psychopathic personality. But in Galbraith v HM Advocate (2002) JC 1 it was held that the formula in Savage was not to be read in a narrow sense, and it was not necessary that all the criteria in that formula had to be present. Furthermore, although the plea had to be based on some form of mental abnormality, that condition need not be one bordering on insanity. Instead the court ruled that diminished responsibility required the existence of an abnormality of mind which had the effect that the accused's ability to determine or control his actings was substantially impaired. However, the Court excluded from the scope of the plea:

1. any condition brought on by the consumption of drink or drugs, and
2. psychopathic personality disorder.

References

• Boland, F, Diminished Responsibility as a Defence in Irish Law, (1995) 5 Irish Criminal Law Journal 193.
• Boland, F, Diminished Responsibility as a Defence in Irish Law: Past English Mistakes and Future Irish Directions, (1996) 5 Irish Criminal Law Journal 19.
• Butler Committee (1975) The Butler Committee on Mentally Abnormal Offenders (London: HMSO) Cmnd 6244.
• Dell, S, Diminished Responsibility Reconsidered, (1982) CLR 809.
• Griew, E, Reducing Murder to Manslaughter: Whose Job? (1986) 12 Journal of Medical Ethics 18.
• Griew, E, The Future of Diminished Responsibility, (1988) CLR 75.
• Scottish Law Commission. Discussion Paper on Insanity and Diminished Responsibility. Discussion Paper No 122. (2003) [1]