Rationale: Rates of attempted suicide for individuals with schizophrenia are approaching 30%. Attempted suicide is among the most potent predictors of subsequent suicide. Several studies suggest that suicide is more likely to occur in patients who are not being adequately treated or not being treated at all. An effort was made in the last decade to evaluate the antisuicide effects of pharmacological treatment in schizophrenia with emphasis on the role of the newer second-generation antipsychotics (SGA).
Objective: The aim of the present study was to assess in a large cohort of schizophrenia patients the effects of exposure to SGA on suicidality of patients suffering from schizophrenia or schizoaffective disorder. The study is a retrospective case-controlled evaluation over a 5-year period undertaken in a large university affiliated tertiary care psychiatric hospital.
Methods: Between January 1998 and December 2002, all records of admissions of schizophrenia or schizoaffective disorder patients (ICD-10) were assessed. Data as to age, gender, diagnosis, suicide attempt prior to admission, treatment with antipsychotic medication, dose and duration of treatment (mg daily, duration) with SGA was extracted from patients' files. All patients who had attempted suicide prior to admission were defined as the index group. The case-controlled group was comprised of the next admission of a patient suffering from schizophrenia (or schizoaffective disorder), matched for gender and age, who did not attempt suicide.
Results: Records of 756 patients (4486 admissions for said period) were analyzed (56.6% male, mean age 39.1+/-13.5 years). Amongst 378 patients who attempted suicide (index group), 16.1% were exposed to SGA while 37% were exposed in the control group (P=0.0001). The protective effect (odds ratio) of treatment by SGA was 3.54 (95%CI: 2.4-5.3). Risperidone was more frequently prescribed in the control group (54.3%) and had a larger effect-size than olanzapine (3.16 versus 1.76), although not statistically significant. Clozapine was prescribed only to a few patients.
Conclusions: Schizophrenia patients exposed to both risperidone and olanzapine may gain protection from suicidality. The antisuicide effects seem to differ between SGAs. The long duration and large sample size support this finding, despite the retrospective nature of this study.