Forty-one subjects between 12 and 63 years of age with a complaint of nocturnal wandering were reviewed retrospectively, and a prospective investigation of their compliance to treatment was performed. Twenty-nine of 41 subjects committed violence against themselves or others (''violent group''). Clinical investigation of their problem involved polysomnography, wake and sleep EEGs and ambulatory EEG recording in the home environment. The nocturnal wandering may have started from NREM sleep or REM sleep, and violence was observed in both of these sleep states. Arousal from sleep may have been triggered by sleep-disordered breathing or may have been related to temporal lobe abnormalities, and, in some cases, no abnormal polygraphic features were noted. Violence was always preceded by many instances of nocturnal wandering that had received little clinical attention. Temporal lobe abnormalities, a rare cause of nocturnal wandering, were present only in the ''violent'' group. This group also had a higher percentage of men than the ''nonviolent'' group. In both groups, the frequency of nocturnal wandering increased with an increase in daytime stressors. Pharmacological and psychiatric treatment approaches were beneficial in both groups.
