Alcohol‐induced sleepwalking or confusional arousal as a defense to criminal behavior: a review of scientific evidence, methods and forensic considerations

Abstract

Summary An increasing number of criminal cases have claimed the defendant to be in a state of sleepwalking or related disorders induced by high quantities of alcohol. Sleepwalkers who commit violent acts, sexual assaults and other criminal acts are thought to be in a state of automatism, lacking conscious awareness and criminal intent. They may be acquitted in criminal trials. On the other hand, criminal acts performed as the result of voluntary alcohol intoxication alone cannot be used as a complete defense. The alcohol‐induced sleepwalking criminal defense is most often based on past clinical or legal reports that ingestion of alcohol directly ‘triggers’ sleepwalking or increased the risk of sleepwalking by increasing the quantity of slow wave sleep (SWS). A review of the sleep medicine literature found no sleep laboratory studies of the effects of alcohol on the sleep of clinically diagnosed sleepwalkers. However, 19 sleep laboratory studies of the effects of alcohol on the sleep of healthy non‐drinkers or social drinkers were identified with none reporting a change in SWS as a percentage of total sleep time. However, in six of 19 studies, a modest but statistically significant increase in SWS was found in the first 2–4 h. Among studies of sleep in alcohol abusers and abstinent abusers, the quantity and percentage of SWS was most often reduced and sometimes absent. Claims that direct alcohol provocation tests can assist in the forensic assessment of these cases found no support of any kind in the medical literature with not a single report of testing in normative or patient groups and no reports of validation testing of any sort. There is no direct experimental evidence that alcohol predisposes or triggers sleepwalking or related disorders. A legal defense of sleepwalking resulting from voluntarily ingested alcohol should be consistent with the current state of art sleep science and meet generally accepted requirements for the diagnosis of sleepwalking and other parasomnias.

Zolpidem Ingestion, Automatisms, and Sleep Driving: A Clinical and Legal Case Series

“…15 The prevalence of sleep walking suggests that there might be coincidental overlap in some patients who are prescribed hypnotic sedatives. The likelihood of sleepwalking and other NREM parasomnias is increased by factors or conditions that increase slow wave sleep (such as sleep deprivation) or cause 34 Such a defense would seem to be stronger if there is a history of prior parasomnia and if the medication was used properly.…”

Role of the Expert Witness in Sleep-Related Violence Trials

“…In the case of alleged assault that I am discussing, the defense attorney hired a medical expert who supported the sleepwalking defense based primarily upon the premise that alcohol ingestion was the immediate trigger for the event. A recent thorough review of the scientific literature reveals, however, that there is no direct experimental evidence that alcohol predisposes or triggers sleepwalking or related disorders [13]. It is my belief that the sleepwalking defense should only be considered after other conditions have been exhausted and that consideration should be first given to the relative risks of violence and sexual crimes following episodes of clear alcohol intoxication.…”

An Essay on Sleep-Related Sexual Behaviours and Offences Related to Sexual Behaviours

“…His review is preceded with pertinent questions for the forensic area:" Table 2) and controversially use an alcohol provocation test in their sample case. Their work has led to some controversy [32][33][34][35][36][37][38][39][40].…”