Objective: The study examined the extent to which delusions motivate violent behavior among psychiatric patients with a history of delusions.
Methods: Fifty-four psychiatric inpatients identified by hospital staff as having delusions were interviewed about their history of delusions and incidents of violence that were concurrent with delusions. Raters used a 5-point scale to estimate the degree to which each reported incident of violence was motivated by a concurrent delusion. A second set of raters used a 5-point scale to estimate the severity of the violent incidents.
Results: Raters' mean estimate indicated overall that violent incidents were probably not motivated by concurrent delusions. However, a significant minority of violent subjects (40 percent) reported at least one violent incident that was judged to be probably or definitely motivated by a concurrent delusion. A smaller subgroup of violent subjects (17.5 percent) reported at least one incident that was judged to be both extremely violent and definitely motivated by a concurrent delusion.
Conclusions: Delusional motivation of violence is rare, but a moderate risk exists that delusions will motivate violence at some time during the course of a violent patient's illness.