Predicting suicidal risk in schizophrenic and schizoaffective patients in a prospective two-year trial

Background: Enhanced ability to reliably identify risk factors for suicidal behavior permits more focused decisions concerning treatment interventions and support services, with potential reduction in lives lost to suicide. Methods: This study followed 980 patients at high risk for suicide in a multicenter prospective study for 2 years after randomization to clozapine or olanzapine. A priori predictors related to diagnosis, treatment resistance, and clinical constructs of disease symptoms were evaluated as possible predictors of subsequent suicide-related events. Results: Ten baseline univariate predictors were identified. Historical predictors were diagnosis of schizoaffective disorder, history or current use at baseline of alcohol or substance abuse, cigarette smoking, number of lifetime suicide attempts, and the number of hospitalizations in the previous 36 months to prevent suicide. Predictive clinical features included greater baseline scores on the InterSePT scale for suicidal thinking, the Covi Anxiety Scale, the Calgary Depression Scale (CDS), and severity of Parkinsonism. Subsequent multivariate analysis revealed the number of hospitalizations in the previous 36 months, baseline CDS, severity of Parkinson's, history of substance abuse, and lifetime suicide attempts. Clozapine, in general, was more effective than olanzapine in decreasing the risk of suicidality, regardless of risk factors present. Conclusions: This is the first prospective analysis of predictors of suicide risk in a large schizophrenic and schizoaffective population judged to be at high risk for suicide. Assessment of these risk factors may aid clinicians in evaluating risk for suicidal behaviors so that appropriate interventions can be made.