This study examined the proximate causes of psychotic patients’ aggression upon the admission to the psychiatric wards of a university and two state hospitals.

The authors used a semistructured interview to elicit proximate causes of assaults from the assailants and victims. The treating psychiatrists and nurses provided additional information. Based on this interview, aggressive episodes were categorized as psychotic, impulsive and planned.

A total of 820 assaults committed by 289 newly admitted violent psychotic inpatients were evaluated. The interview ratings indicated that 76.71% of the assaults were directly driven by psychotic symptoms and 22.32% of all attacks were labeled as impulsive. Only 0.98% of assaults were categorized as planned.

These findings indicate that assaultive behavior among recently admitted acute psychiatric inpatients with untreated or undertreated psychosis is primarily driven by psychotic symptoms and disordered impulse control. Because each type of assault requires a different management, identifying the type of assault is crucial in determining treatment interventions.