Schizophrenia and impulsive aggression: a heuristic inquiry with forensic and clinical implications

Assessment of a violent act committed by an offender with schizophrenia typically focuses on whether the act was due to distortions in thought or perception, i.e., delusions or hallucination. An important but less appreciated feature is the impulsivity of the act, which can have forensic and therapeutic implications. Here a modification of Barratt's classification of aggressive behavior is presented that includes premeditated (instrumental), medical (secondary), impulsive (expressive), and compulsive (instrumental and expressive) aggression. Violence due to a mental condition such as schizophrenia is considered medical, but even aggression motivated by delusions or hallucinations can also be characterized as impulsive, premeditated, or compulsive.Although research on aggression and schizophrenia is limited with regard to the impulsivity-premeditation dimension and difficult to compare, current evidence suggests this to be an important consideration in the assessment of aggression in individuals with schizophrenia, important both forensically and therapeutically. Future research on the impulsive-premeditated quality of aggressive acts by offenders with schizophrenia--research wherein aggressive behavior is defined, situational context is clarified, and diagnostic criteria are explicitly followed--should further refine our understanding of the nature of aggressive acts associated with schizophrenia. Findings from such research will undoubtedly inform assessment, treatment, and forensic relevance of schizophrenia-related physical aggression.