Study objectives: To review medical and legal case reports to determine how many appear to support the belief that violence against other individuals that occurs during Disorders of Arousal - sleepwalking, confusional arousal, and sleep terrors - is triggered by direct physical contact or close proximity to that individual and does not occur randomly or spontaneously.

Design: Historical review of case reports in the medical and legal literature.

Measurements and results: A total of 32 cases drawn from medical and legal literature were reviewed. Each case contained a record of violence associated with Disorders of Arousal; in each, details of the violent behavior were available. Violent behaviors associated with provocations and/or close proximity were found to be present in 100% of confusional arousal patients and 81% of sleep terror patients. Violent behaviors were associated with provocation or close proximity in 40%-90% of sleepwalking cases, depending on whether the legal verdict and other factors were taken into account. Often the provocation was quite minor and the response greatly exaggerated. The specific manner in which the violence was triggered differed among sleepwalking, confusional arousals, and sleep terrors.

Conclusions: In the cases reviewed, violent behavior directed against other individuals associated with Disorders of Arousal most frequently appeared to follow direct provocation by, or close proximity to, another individual. Sleepwalkers most often did not seek out victims, but rather the victims sought out or encountered the sleepwalker. These conclusions are tempered by several limitations: the selection of cases was not random and may not represent an accurate sample of violent behaviors associated with Disorders of Arousal. Also, final verdicts by juries in reported legal cases should not be confused with scientific proof of the presence or absence of sleepwalking. The pathophysiology of Disorders of Arousal with and without violent behavior could be associated with normally occurring deactivation of the frontal lobes during slow wave sleep (SWS) connected via atypically active thalamocortical pathways to the limbic areas. It is not known if the violent sleepwalker, confusional arousal patient, or sleep terror patient differs from other patients with these disorders. The conclusions of this case series await confirmation by the results of future sleep laboratory based studies.