A polysomnographically documented case of adult somnambulism with long-distance automobile driving and frequent nocturnal violence: parasomnia with continuing danger as a noninsane automatism?

A case of childhood-onset somnambulism is reported in which a 43-year-old man presented with repeated sleep-related injuries incurred during violent nocturnal activity, which included frenzied running, throwing punches and wielding knives. He had also driven an automobile a long distance during a presumed somnambulistic state. His wife had been repeatedly injured, and she felt that her life was threatened by his nocturnal violence 2-3 times yearly. Polysomnography (PSG) documented multiple episodes of complex and violent behaviors arising exclusively from stage 3/4 sleep, thus confirming the diagnosis of somnambulism. Other causes of sleep-related violence were excluded. The patient responded promptly to treatment with bedtime clonazepam, and benefit was maintained at 5-year follow-up. Although this strictly clinical case did not have any legal repercussions, it does carry forensic implications, particularly when placed in the context of the published medical literature on PSG-documented parasomnias (somnambulism, rapid eye movement sleep behavior disorder) containing explicit examples of recurrent violence, at times life-threatening, directed toward the bed partner and others. Thus, a new medical-legal concept is proposed, consisting of "parasomnia with continuing danger" as a noninsane automatism. Treatment guidelines, within the context of forensic medicine, are presented.