Neurocognitive features in male patients with schizophrenia exhibiting serious violence: a case control study

BACKGROUND The relationship between violence and neurocognitive function in schizophrenia is unclear. We examined the backgrounds and neurocognitive functions of violent and nonviolent patients with schizophrenia to identify factors associated with serious violence. METHODS Thirty male patients with schizophrenia who were hospitalized after committing serious violent acts were compared with 24 hospitalized male patients with schizophrenia and no history of violence. We evaluated psychiatric symptoms using the Positive and Negative Syndrome Scale (PANSS) and neurocognitive functions using the Brief Assessment of Cognition in Schizophrenia (BACS)-Japanese version. RESULTS Repeated-measures analyses of variance on BACS subcomponents z-scores showed that the violent and control groups had different neuropsychological profiles at trend level (p = 0.095). Post hoc analyses of variance indicated that the violent group had significantly better working memory and executive function than the control group. In post hoc ANOVAs also controlling for the effect of the presence of substance abuse on cognitive function, violent or nonviolent group had a significant main effect on executive function but not on working memory. CONCLUSIONS Patient with violent or non-violent schizophrenia have distinct neuropsychological profiles. These results may help develop improved psychosocial treatments.