Fifty adults with either a present or past complaint of somnambulism were evaluated to determine the development and clinical course of their disorder as well as their personality patterns. Generally, when sleepwalking was outgrown, its onset was before age 10 years and its termination before age 15 years. Current sleepwalkers, compared with past sleepwalkers, started sleepwalking at a later age, had a higher frequency of events, and had episodes earlier in the night. Their episodes were also characterized by more intense clinical manifestations. Furthermore, current sleepwalkers demonstrated high levels of psychopathology, whereas past sleepwalkers had essentially normal psychological patterns. Specifically, the current sleepwalkers showed active, outwardly directed behavioral patterns, suggestive of difficulties in handling aggression. The clinical application of these findings is discussed and practical recommendations are given for the evaluation and management of sleepwalking.