Therefore it can be seen that the law draws a distinction between automatism caused by a disease of the mind and that which is not caused by a disease of the mind. The first, insane automatism follows the McNaughten rules, and if pleaded successfully, the verdict would be not guilty by reason of insanity. However, the second, sane automatism, provides an acquittal, (Quick), unless the condition is self inflicted (Lipman (1970)).
Following this there have been two approaches used by the court in determining sane or insane automatism. First of which is the Continuing Danger theory. This concerns the likelihood of the condition presenting a recurring danger to the public. If so, the condition should be treated as insane. In Bratty, Lord Denning stated, “A mental disorder which has manifested itself in violence and is prone to recur is a ‘disease of the mind.’ However, it must also be noted that even where there may be no danger of recurrence, it is not conclusive that this would be non- insane automatism. For example, in the sleepwalking case of Burgess (1991) Lord Lane said, “a danger of recurrence may be an added reason for categorising the condition as a ‘disease of the mind’ but presence or otherwise of recurrence is not conclusive.” This test was also suggested in the case of Sullivan (1984), however, the Judge said, that it was irrelevant whether the source of the defect was “permanent or transient and intermittent, provided that it subsisted at the time of the commission of the act.”
The second approach that has been used by the courts is the ‘External Factor’ theory. The inability of the defendant to control his or her acts must result from the operation of some external factor upon the working of the brain, rather than an inherent mental defect to be non-insane automatism. In Quick (1973) the Judge stated, “A malfunctioning of the mind of transitory effect caused by the application to the body of some external factor such as violence, drugs, including anaesthetics, alcohol and hypnotic influences cannot fairly be said to be due to disease.” The external factor test was introduced in this case, involving a hypo-glycaemia diabetic who failed to eat after injecting insulin. The Judge commented, it would be “an affront to common sense to detain a diabetic when pushing a lump of sugar into his mouth would cure his problem” However, Where the cause of the behaviour is 'internal' such as a 'disease of the mind' or a disease of the body the relevant defence will be that of insanity rather than automatism such as in the case of Hennessy (1989). In this case of a hype-glycaemia diabetic it was the diabetes that caused the condition and not the insulin. As an external factor was not present this was deemed to be insane automatism. This is also the case with epilepsy, in Sullivan the defendant was held to be legally insane as it was held to be a ‘disease of the mind.’ The disease of the mind was given the very large scope of an impairment of “reason, memory and understanding.”
In light of these decisions it is surprising that in the case of T (1991), the court accepted that post traumatic stress, a disease of the mind, could satisfy automatism. However, because this condition had been caused by an outside factor, rape, the Judge allowed automatism to be put to the jury.
In Hennessy, D also claimed to be having marital problems which had caused him stress and anxiety, arguing that these were external factors. However, the judge rejected this argument, as “stress, anxiety and depression are not in themselves separately or together external factors of the kind capable in law of causing or contributing to a state of automatism.”
The issue of ‘self induced’ automatism needs also to be taken into account. A defendant may be prevented from raising the defence of automatism where there is evidence to show that he was in some way at fault in bringing about the state of automatism. If, for example, the defendant takes dangerous drugs, making him at fault in bringing about the autonomic state, he has a defence to crimes of 'specific intent', but not to those of 'basic intent'. ; In the case of Bailey, D would have a defence if he did not realise that failing to eat would put him into a state in which he might attack someone. However, he ought not to have an offence if he did realise this, therefore being reckless in failing to eat.
In the condition of sleepwalking the law is unsettled and highly unsatisfactory, and has not been followed in other Commonwealth countries. The British case of Burgess (1991) the defendant attacked his girlfriend whilst asleep, and pleaded the defence of automatism to a charge of unlawful wounding. The trial judge ruled that the defendant was pleading insanity, as sleepwalking was an internal disorder. However, as this is the only authority, this constitutes a weak area of the law. The Canadian case of Parks (1990), the defendant’s loss of memory, reason and understanding was said to be caused by sleep, not sleepwalking. Therefore, the underlying cause was not a disease of the mind, therefore not a ‘disease of the mind’ under the McNaughten rules. These cases indicate that the defence may be more straightforward and approachable if this distinction was eradicated, and it is also not suggested in the Bratty description of automatism.
There is also very little direct authority in the area of Psychological blow automatism. The case of Falconer (1990) shows how the defence may be simplified. The defendant shot her husband, saying that he had sexually assaulted her; she claimed she could remember nothing, and on appeal it was held that automatism was available to her. The standard here was based on the ‘ordinary person.’ It can be proved that D was below this standard, insane automatism would be the outcome, but if they were above this standard, they would be considered a sane automaton. The Australian case of Radford (1985) dismissed the internal/external distinction, and it was held that it only matters whether the defendant was of sound or unsound mind.
The evidential burden in establishing the defence lies on D, he must produce sufficient evidence of automatism for a jury to decide upon. Whether or not he has done so is a matter of law for the trial judge, but it is apparent from the decided cases dealing with the defence that the defendant will need to produce some expert medical evidence as to his mental and physical state at the time of the offence, such as Hill v Baxter, “You must bring forward credible evidence to assign the course of action to an involuntary act.” Following Bratty and Woolmington v DPP there is a presumption that the act you commit is voluntary and that D is sane, which has to be disproved. However, the ultimate burden is on the prosecution to prove that D’s act was in fact, voluntary. The evidential burden here is high and if a defendant pleads insanity through a ‘defect of reason’ and the jury rejects this, it is not then possible to plead automatism if evidence only points towards insanity.
Automatism is a complete defence in that if the defendant succeeds in establishing it, he will be acquitted. This factor may explain the reluctance of the courts to recognise the defence of automatism in certain situations. Where a defence of automatism is raised, the courts will have to consider whether the defendant should in fact be classed as criminally insane.
Therefore, the defence of automatism is a great deal more complicated to prove than the quote from Bratty suggests, especially due to the distinction between external and internal causes of the ‘disease of the mind.’ However, it is largely accurate in its basic portrayal of the way in which the term ‘automatism’ is viewed in law.
There have been a number of criticisms to the defence of automatism, the main one being that distinguishing between internal and external causes leads to absurd and irrational distinctions - such as that drawn between Hennessy and Quick. The main reason given for the difference is that automatism caused by an internal factor, namely a disease, is more likely to recur than such a state caused by an external factor. This may be true of a comparison between an automatic state caused by a long-term mental illness, and one caused by a blow to the head, but as the cases on diabetes show, the distinction can be tenuous.
The draft Criminal Code proposes maintaining the law on automatism as it stands, because the public interest is best served by the complete acquittal of anyone who acts while in a condition of non-insane automatism. This may be reasonable for the one-off offender, however, it offers no public protection against someone who is prone to recurring states of automatism through an external factor.
Also the distinction between internal and external causes could be abolished. Reform of the insanity defence to bring it in line with medical descriptions would aim towards this; behaviour that was allegedly automatic but clearly did not fall within medical definitions of insanity could then be considered solely in the light of the danger of recurrence, and the element of recklessness in the behaviour of the accused.