Violence and severe mental illness: the effects of substance abuse and nonadherence to medication.

OBJECTIVE Violent behavior among individuals with severe mental illness has become an important focus in community-based care. This study examines the joint effect of substance abuse and medication noncompliance on the greater risk of serious violence among persons with severe mental illness. METHOD Involuntarily admitted inpatients with severe mental illness who were awaiting a period of outpatient commitment were enrolled in a longitudinal outcome study. At baseline, 331 subjects underwent an extensive face-to-face interview. Complementary data were gathered by a review of hospital records and a telephone interview with a family member or other informant. These data included subjects' sociodemographic characteristics, illness history, clinical status, medication adherence, substance abuse, insight into illness, and violent behavior during the 4 months that preceded hospitalization. Associations between serious violent acts and a range of individual characteristics and problems were analyzed by using multivariable logistic regression. RESULTS The combination of medication noncompliance and alcohol or substance abuse problems was significantly associated with serious violent acts in the community, after sociodemographic and clinical characteristics were controlled. CONCLUSIONS Alcohol or other drug abuse problems combined with poor adherence to medication may signal a higher risk of violent behavior among persons with severe mental illness. Reduction of such risk may require carefully targeted community interventions, including integrated mental health and substance abuse treatment.