Violence in schizophrenia patients may result from many factors besides the symptoms of schizophrenia. This study examined the relationship between childhood antisocial behavior and adult violence using data from the NIMH CATIE study. The prevalence of violence was higher among patients with a history of childhood conduct problems than among those without this history (28.2% vs. 14.6%; P < 0.001). In the conduct-problems group, violence was associated with current substance use at levels below diagnostic criteria. Positive psychotic symptoms were linked to violence only in the group without conduct problems. Findings suggest that violence among adults with schizophrenia may follow at least two distinct pathways—one associated with premorbid conditions, including antisocial conduct, and another associated with the acute psychopathology of schizophrenia.