Large social cognitive impairments characterize homicide offenders with schizophrenia

Schizophrenia is associated with an increased violence risk, particularly homicide. One possible, but scarcely explored, contributor to the increased violence risk is social cognitive impairment. Individuals with schizophrenia show impairments in social cognition that are associated with poor functional outcome. This study examined social cognition among homicide offenders with schizophrenia (HOS), applying validated measures of emotion perception and theory of mind (ToM). Two groups of individuals with schizophrenia were compared, one had committed homicide (HOS, n = 26), and the other had no violence history (non-HOS, n = 28). Healthy controls (HC, n = 71) were included as reference group for one measure. Emotion perception was indexed by the Emotion in Biological Motion (Emotion) and Pictures of Facial Affect (PFA) tests. ToM was assessed with the Hinting Task and Movie for the Assessment of Social Cognition (MASC). The results showed that HOS participants had significantly poorer performance than non-HOS in both emotion perception and ToM. For the MASC test, HOS participants showed large deficits compared to HC (-4 standard deviations). Particularly, HOS participants made a substantial number of undermentalizing errors. The results suggest that emotion perception deficits and a tendency to undermentalize may be important for understanding homicide in schizophrenia.