Evaluate the development of the criminal law in relation to the defence of insanity.

        For a defence of insanity, the rules have established that three conditions need to be satisfied: first that the accused was suffering from a disease of the mind; second, that this gave rise to a defect of reason; and third, that as a result he either did not know that what he was doing was wrong.

        Disease of the mind is a legal term not a medical one. The law is primarily concerned with whether the accused is to be held legally responsible for his acts; this will depend on his mental state and its compliance with the legally defined criteria. The problem here however is that, not all medical conditions of the mind meet the legally defined criteria and vise versa. This creates a problem for the medical witness in deciding whether he should speak the language of the psychiatrist or convert these terms into what he believes they equate to in the legal terminology. If the psychiatrist seeks to translate medical terms into legal terms there is a danger that he will subvert the role of the jury by answering which are for their consideration, whereas, if he does not and simply confines himself to the role of the expert witness giving evidence for the jury’s evaluation, there is a danger that he will mystify the jury.

        So the question inevitably falls upon to what amounts to a legal definition of ‘disease of the mind’. Let us now look at how common has adapted this principle. It was argued in Kemp that ‘disease of the mind’ meant that there had been an organic disease of the brain, which had caused degeneration of the brain.

Devlin J stated (at p. 407):

“ The law is not concerned with the brain but with the mind. In my judgment the condition of the brain is irrelevant and so is the question whether the condition of the mind was curable or incurable, transitory or permanent”.

This dictum received the approval of Lord Denning in Bratty, who added a further gloss, stating (at p. 412):

“Any mental disorder which has manifested itself in violence and is prone to recur is a disease of the mind. At any rate it is the sort of disease for which a person should be detained in hospital rather than be given an unqualified acquittal”

This statement has only added to the confusion of the definition as, diseases of the mind may manifest themselves in other ways, which do not involve violence, there are also conditions which manifest themselves in violence which do not fall within the definition as the case of Quick (failure to take insulin) demonstrates. The Judge ruled that the defence of automatism amounted to a plea of insanity, and as a result the defendant pleaded guilty rather face the jury returning the special verdict. However, the Court of Appeal quashed the conviction, with Lawton LJ interpreting the phrase ‘disease of the mind’ to mean a ‘malfunctioning of the mind caused by disease’ and it was held: that, malfunctioning of the mind caused by some external factor cannot fairly be said to be to be due to a to a disease. The use of such criterion to distinguish insanity from automatism seems somewhat fatuous. For example, hypoglycaemic coma is an internal cause, which results from an overproduction of insulin by the pancreas, and should the sufferer of such disease commit an offence the result would be the finding of insanity. Is a person suffering from such a condition more deserving of the label ‘criminally insane’ than a diabetic who fails eat after insulin2? The current state of law fails to clarify this.

        

        The case of Sullivan gives us further scope as to the frailties within the legal definition ‘disease of mind’. The defence was raised that, the attack was committed in the course of an epileptic seizure and he was not aware of doing it. It was held however that the defence of automatism was really a defence of insanity, which resulted in the defendant changing his plea from not guilty to guilty.

Sullivan indicates, the defences of insanity and automatism are closely linked, as for both defences the accused has acted while not in control of his mental faculties. However, Lord Diplock stated that the defence of automatism would only be available where temporary impairment resulted from an external physical factor. This would demonstrate that a person suffering a epileptic attack who commits an offence would be presumed insane for the purpose of criminal liability whereas a diabetic in hypoglycaemic coma, caused by low low-sugar, is not. By contrast, however, a diabetic in hyperglycaemic coma, caused by high blood-sugar level, is insane.

It seems rather absurd that conditions such as diabetes or epilepsy, which do not fall within the medical definition of mental disorders, would fall within the legal definition under the M’Naghten Rules.

        It is therefore submitted that the Lords in attempting to define ‘disease of mind’ in later cases, have prevented those who seek to use the defence of automatism who might be otherwise considered sane and labelling them insane instead. It may also prevent those who are seeking to use to defence of insanity, as although a ‘disease of the mind’, may be medically proven it may fail to meet the legal criteria of the definition. This has resulting in many defendants changing their plea to guilty, rather than face the operation of an insanity defence, demonstrating a great deal of dissatisfaction with the defence, as the burden proof is reversed and placed upon the defendant to prove they are insane on the balance of probability. One might query whether this is a breach of Article 6(2) of the European Convention on Human Rights (which provides that everyone charged with a criminal offence shall be presumed innocent until proved guilty). It is quite clear that those who are deemed fit to plead have a difficult decision of whether to put their mental incapacity before the court, the risk in doing so, would require the application of the M’Naghten Rules, which remains the test for insanity in the eyes of the law.

The House of Lords has been reluctant to budge from the principles laid down in the M’Naghten Rules, despite persistent criticism by lawyers and medical officials on several grounds. First of which, they do not reflect current psychiatric thinking on mental disorder. One must point out that the rules were made in 1843 when there was limited understanding of mental illness, and the development in technology has given a greater scope of mental capacity, the rules have failed to be updated to reflect modern society. Secondly, it has led to absurd decisions (as discussed). Thirdly, it has failed to cover provisions under the Mental Health Act 1983.

        Arguments about reforming the insanity defence have continued on and off for decades. The debate was given renewed impetus by the Butler Report and by the Law Commission’s reworking of the Report in the Draft Code. The Butler proposals form basis the for the mental disorder provisions in the Draft Code. The Draft Code abandons the language used in the M’Naghten Rules and replaces them with medical terminology such as ‘mental disorder’, ‘severe mental illness’ and ‘severe mental handicap’. Clause 34 contains definitions, which clarify the conditions which amount to a ‘mental disorder’, this has a broader range of effects for criteria needed for a mental disorder verdict, which are not covered by the M’Naghten Rules.

        There is a possible deficiency in these definitions, as ‘severe mental illness’ does not cover cases where a characteristic of the illness is uncontrollable impulses, this would result in the unavailability of the defence which may result in a conviction. However, although a there is a need for a slight retuning of the Draft Code the provisions would ensure that it met the criteria The Mental Health Act.

        As we have demonstrated there is a clear need for reform in the law relating to the defence of insanity. A medical based test seems to take a better direction, as it would give greater impetus on medical knowledge of the workings of the mind, which is vital to establish whether the accused are culpable for their actions.

 The disease can be a mental disease or a physical disease, which affects the mind (Sullivan (1984)). Any mental illness, which has manifested itself in violence and is prone to recur, is a disease of the mind (Bratty (1963), Burgess (1991)). The disease can be of any part of the body if it has effect on the mind; for example, arteriosclerosis affecting the flow of blood to the brain (Kemp (1957); or high blood sugar levels because of diabetes (Hennessey (1989)). The disease can be one, which causes a transient or intermittent impairment of reason, memory or understanding. The condition need not be permanent (Sullivan (1984)). Where the cause is external and not a disease, then this is not insanity; for example the effect of a drug (quick (1973)).

        The defect of reason must be more than absent-mindedness or confusion (Clarke (1972)). It must be due to a disease, which affects the mind.

        Disease of the mind is a legal term not a medical one. The disease can be a mental disease or a physical disease, which affects the mind (Sullivan (1984)). Any mental illness, which has manifested itself in violence and is prone to recur, is a disease of the mind (Bratty (1963), Burgess (1991)). The disease can be of any part of the body if it has effect on the mind; for example, arteriosclerosis affecting the flow of blood to the brain (Kemp (1957); or high blood sugar levels because of diabetes (Hennessey (1989)). The disease can be one, which causes a transient or intermittent impairment of reason, memory or understanding. The condition need not be permanent (Sullivan (1984)). Where the cause is external and not a disease, then this is not insanity; for example the effect of a drug (quick (1973)).

        The concept of insanity is at the heart of debates about the effect of the accused mental state. The scope and limits of insanity are a major factor in shaping other defences founded on states of automatism, intoxication and diminished responsibility. More fundamentally, the recognition of an insanity defence is a mark of the maturity and humanity of the criminal law. As the Royal Commission on Capital punishment commented fifty years ago, “it has for centuries been recognised that, if a person was, at the time of his unlawful act, mentally so disordered that it would e reasonable to impute guilt to him, he ought not to be held liable to conviction and punishment under criminal law”.

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