Sleepwalking defense in murder trials

Sleepwalking, scientifically called somnambulism, is becoming more and more common among population. In fact, some sleepwalkers are capable of violent actions while sleepwalking and it may have tragic implications, even the death of the victim. Every case where the sleepwalking defense is raised is quickly gaining publicity, as it tackles numerous legal, medical and ethical issues.

Sleepwalking is a complex phenomenon, which consists of multiple actions. Even though scientists are able to characterize nature of sleepwalking, one question is left unanswered: what is the degree of control exhibited by sleepwalkers? The conflict of views on the nature of sleepwalking creates controversy especially when the future of the defendant is at stake.

The first success of sleepwalking defense happened during Boston trial in 1846 when Albert Tirrell was acquitted of his lover's murder on basis of sleepwalking defense. However, there was no steady pattern for success of sleepwalking defense. Obliviousness to pain, a strong family history of parasomnias were the decisive factors for acquittal. Nonetheless, jury often considered actions of sleepwalkers to be too complex for involuntary actions and found sleepwalkers quilty.

To analyze this tendency, it is necessary to look into existing classification of sleepwalking defense. Automatism, insanity and unconsciousness are major types of this defense. In case of automatism the defendants should prove that their actions were the result of involuntary bodily movement. In R v Parks (Canada) sleeping was determined as automatism because sleepwalking is neither a neurological, nor a psychiatric illness. However, defendants who could use it tend to rely instead on a defense of insanity or diminished capacity due to existing biases towards sleepwalking. Unconsciousness and insanity defenses are based on denial of a criminal intent.

Unconsciousness means temporary mental incapacitation, which happens when a person suddenly loses control over his mind. In case of insanity the defendant has a permanent mental disease or defect. Nowadays, it is suggested to introduce a unique sleepwalking defense with the burden of proof on the defendant. This approach will ensure the complex evaluation of medical evidence and create a basis for specific examination of each sleepwalking case. The evidence can include the laboratory data (i.e. brain scans) and data on family history of sleepwalking

The rarity of offences committed by sleepwalkers often discourage experts from dealing with it. However, the further research in this direction has an ultimate value in its medical, legal, and philosophical aspects. Finding the proper approach to sleepwalkers in trial will ensure the main aims of criminal law. There are should be rules for medical examination in cases of sleepwalking, where basic ideas of sleepwalking defense are incorporated.

Исследование выполнено в рамках реализации комплекса мероприятий Программы стратегического развития ПетрГУ на 2010-2016 гг.

А. О. Штромберг