The objective of this study is to determine whether violence in psychiatric patients is associated with brain dysfunction independent of substance abuse. Psychiatric inpatients with a history of violent behavior in the community were compared to nonviolent inpatients on several variables related to brain dysfunction. The two groups were similar in terms of demographics and psychiatric diagnosis. No significant differences were found in neuropsychological function, but violent patients were significantly more likely to have co-occurring substance abuse and nearly 4 times more likely to have a history of closed-head injury. Logistic regression revealed that the association between violence and head injury can be explained by comorbid substance abuse.