Risk factors for suicide in schizophrenia: findings from a Swedish population-based case-control study

Previous reports regarding risk factors for suicide in schizophrenia have been inconclusive. We performed a matched case-control study of in-patient-treated schizophrenia patients in order to assess the suicide risk associated with socioeconomic, demographic, and psychiatric factors. The cases were 84 patients who died by suicide within five years after diagnosis in a cohort of all patients discharged for the first time from psychiatric hospitals in Stockholm County, Sweden, with a diagnosis of schizophrenia, schizophreniform disorder or schizoaffective disorder between the years 1984 and 2000. One control was individually and randomly matched with each case from the same cohort by date (+/-1 year) and age (+/-5 years) at index diagnosis. Data were retrieved from clinical records of the case-control pairs in a blind fashion. Of the suicides, 54% were men and 46% were women. In multivariate analyses, higher educational attainment (odds ratio [OR] 3.0, 95% confidence interval [CI] 1.03-8.0), age >or=30 years at onset of symptoms (OR 4.8, CI 1.1-21.2), and a history of a suicide attempt requiring non-psychiatric medical treatment (OR 5.0, CI 1.6-15.4) were found to be significantly associated with an increased suicide risk. Gender did not significantly affect the suicide risk, nor did a history of self-discharge, compulsory in-patient treatment, substance-use disorder or a family history of mental disorders or suicide. In schizophrenia, certain suicide risk factors may differ from those in the general population. Clinical suicide risk assessment for schizophrenia patients should be performed taking this into account.