Men and women who develop schizophrenia are at increased risk, compared with the general population, to engage in violence toward others and, in so doing, often lay waste to their own lives. The reasons for this finding remain obscure.

The present work aims to analyze the relationship between active symptoms of the disease, substance abuse and violence in schizophrenic patients admitted to a forensic ward in our country (Portugal).

A population of inpatients (male and female) from two forensic wards was studied as to personal and psychiatric history, substance abuse, social and cultural background, family history, symptoms at the time of the violent behavior and patient's insight.

The prevalence of offenses was the highest among male schizophrenic subjects with coexisting substance abuse, and more than half of the schizophrenic offenders also had problems with substance abuse. Most perpetrators were acutely ill at the time of the offence but only a small number was under mental healthcare.

Our results were consistent with those found in classic literature. We hope this will help us start a structured programme in our hospitals in which behavioral factors, substance misuse and social dislocation are managed together with the active symptoms of the disorder in order to prevent such violent behavior and to promote adequate treatment of schizophrenic patients.