Insanity
Diminished responsibility
Automatism
Defence to
All offences
Murder
All offences
Cause
Must be internal
Must arise from a recognised medical condition
Must be external
Definition requires
Disease of the mind
Abnormality of mental functioning
Loss of consciousness
Burden of proof
On the accused
On the accused
On the prosecution
Standard of proof
Balance of probabilities
Balance of probabilities
Beyond reasonable doubt
Outcome if plea successful
Not guilty by reason of insanity
(special verdict)
(Voluntary) manslaughter
Acquittal
2.1 Insanity
Someone might be deemed insane at the time of their trial, and therefore “unfit to plead” (Law Commission 2010).1 Alternatively, they might be considered sane at the time of the trial, but with one or more sides in the case arguing that they were insane at the time the crime was committed.2 It is this latter scenario, in which the so called “special verdict” of “not guilty by reason of insanity” would be given, that is of greater interest in the current context.
In some senses, insanity is both the best place and the worst place to start a consideration of legal approaches to mental disorders and culpability. It is the best place since many of the rules governing the definition of insanity are essentially unaltered since the M’Naghten case of 1843.3 It is the worst place because it is only infrequently used as a defence in the UK, fewer than five times per year throughout most of the 1970s and 1980s (Jefferson 2009). Following the Criminal Procedures (Insanity and Unfitness to Plead) Act 1991, this number has risen to 20–30 special verdicts per year; still a small drop in the ocean of about 90,000 people per annum tried in the Crown Court (Law Commission 2012). It is also a poor place to start since the rules outlined by the presiding judge Lord Tindal CJ (see Sect. 2.1.1) have been interpreted in contradictory ways during the subsequent 170 years.
2.1.1 The M’Naghten Case
In 1843, Scottish woodturner Daniel M’Naghten was put on trial for the murder of Edward Drummond, but was found not guilty by reason of insanity. The judgment might have passed unnoticed except that the intended target was not Drummond, but rather his boss, Prime Minister Robert Peel. Not for the last time, the metaphorical proximity of a national political leader to the crime led to post hoc questioning of the ruling.
The matter was referred to the House of Lords and a debate on the concept of insanity. During the discussion, Lord Tindal observed that: “the jurors ought to be told in all cases that every man is to be presumed to be sane, and to possess a sufficient degree of reason to be responsible for his crimes, until the contrary be proved to their satisfaction; and that to establish a defence on the ground of insanity, it must be clearly proved that, at the time of the committing of the act, the party accused was labouring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he was doing; or, if he did know it, that he did not know he was doing what was wrong.” (quoted by Clarkson et al. 2010: p. 378).
There are several relevant points to note. Firstly, there is the presumption of sanity and, in consequence, responsibility. Secondly, insanity is stated as originating with “disease of the mind”, which thirdly, causes “defect of reason” at the time of the crime. Fourthly, this defect of reason is manifest as a lack of discernment regarding either the nature and quality of the act, or that it was wrong. Because of this emphasis on knowing right from wrong, this has subsequently been referred to as a “cognitive test” of criminal responsibility (in contrast to a “volitional test”, which we will mention later).
2.1.2 Interpretation of the M’Naghten Rules
Pivotal within the M’Naghten rules is the notion of “disease of the mind”. It is this phrase, more than any other, which has proven problematic in the application of the rules both in the UK and overseas. It also has implications when we move on to consider the potential relevance of emerging biological understanding about the workings of the brain (Chap. 3).
Case law has shown that the “disease of the mind” need not be a mental illness, nor indeed a disease at all in a strict medical sense. Probably the most important demarcation to emerge has been the distinction between “internal causes” and “external causes”. For a defence of insanity, the cause must be internal; if the cause is external then it is considered a case of automatism (Sect. 2.3). This distinction has led to a series of judgments which, when seen side by side, look most peculiar; none more so than in regard to diabetic defendants.
A diabetic who was involved in a criminal incident as a consequence of going hypoglycaemic, that is they had excessively low blood sugar, was found to be exhibiting automatism (because the condition is caused by taking insulin, which was deemed to be an external cause),4 whereas another diabetic who went hyperglycaemic (i.e. they have excessively high blood sugar, the natural outcome if they have not taken insulin) was found to be insane.5 As Clarkson and colleagues note “we are left with a law under which some diabetics will be able to secure a complete acquittal while others will be regarded as insane. Such a position is absurd” (Clarkson et al. 2010: p. 383). At other times epilepsy,6 atherosclerosis (hardening of the arteries)7 and sleepwalking8 have all been classified as diseases of the mind leading on to the special verdict.
Anomalies of these kinds have been offered, over many years, as evidence in calls to reform legislation in this area (see Sect. 2.4: Reform of the law). In 2012, the UK Law Commission conducted a consultation on Insanity and Automatism (Law Commission 2012), with their recommendations reported the following year (Law Commission 2013a). Their proposals are outlined in Sect. 2.4 (where it will also be explained why these are unlikely to be enacted in the near future). As it stands, therefore, the definition of insanity remains largely unaltered from M’Naghten.
There have, nonetheless, been some developments in the potential consequences of being found “not guilty by reason of insanity”. As originally drafted, a successful defence of insanity would have led to detention in a secure hospital, possibly “with restrictions”, i.e. until the Home Secretary deemed it appropriate for them to be released. This is clearly inappropriate for a diabetic who failed to remember to take their insulin, or an epileptic who causes harm whilst having a seizure. If the crime was murder, then hospitalisation for life was mandatory.
Since the Criminal Procedures (Insanity and Unfitness to Plead) Act 1991 came into force (in 1992) and was subsequently amended by the Domestic Violence, Crime and Victims Act 2004, judges have been granted more discretion regarding sentencing. A judge can now decide on the basis of medical evidence from two doctors, whether she considers the accused is unfit to plead. If, after this assessment, the judge does elect to go forward to trial, then a “trial of the facts” ensues, in which the prosecution must convince a jury beyond reasonable doubt that the defendant did carry out the crime for which they stand accused. If the jury find against the defendant then the judge can choose from a range of sentences from detention in a psychiatric hospital, with restrictions, down to an absolute discharge.
2.2 Diminished Responsibility
Without being as susceptible to contradictory interpretations as the rules on insanity, there remain a number of complications regarding the defence of diminished responsibility. Most significantly, diminished responsibility is only applicable in cases of murder (or assisting in murder, but not attempted murder).9
Historically, this was appropriate; the defence stems from an era when the punishment for murder would have been execution.10 It is really a partial defence; pleading diminished responsibility was de facto an admission to having killed someone, but offered an avenue for reducing the sentence to, for example, life imprisonment in circumstances where some explanation for the actions of the defendant might be offered. Since we are no longer in the habit of applying death sentences, at least not in the UK, some have argued that diminished responsibility should either be broadened to cover other crimes as well or abandoned as a defence (particularly if the punishment for murder is reduced from the current mandatory life sentence). In the chess game of legislation, claiming diminished responsibility is not without its risks. A successful appeal on these grounds leads inevitably to being found guilty of manslaughter and may still result in a long period of incarceration.
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