The Schizophrenia Suicide Risk Scale (SSRS): development and initial validation

Background: Estimations about the lifetime risk of suicide in schizophrenia vary between 4 and 10%. At present, there does not exist a suicide risk sc ale developed particularly for schizophrenic patients. The aims of the pres ent study were to: (1) develop a clinically useful semi-structured scale fo r the estimation of short-term suicide risk among schizophrenic patients, a nd (2) to carry out an initial validation of the scale. Methods: A 25-item Schizophrenia Suicide Risk Scale (SSRS) was constructed on the base of the literature. The SSRS scores of 69 living schizophrenic patients (LS group) were compared with the scores of 69 schizophrenic suicides (SS group) whose data had been collected previously from The Finnish nationwide and represe ntative psychological autopsy study. Internal consistency of the SSRS was e valuated with Cronbach alpha. The most important SSRS items predicting suic ide were identified with a logistic regression analysis. Sensitivity, speci ficity, positive predictive value, and negative predictive value of the SSR S in predicting suicide with various cut-off scores were calculated. Result s: In the final logistic regression model, the following SSRS items signifi cantly predicted suicide: suicide plans communicated to someone during the past 3 months; one or more previous suicide attempts; loss of professional skills demanding job; depression observed during an interview; and suicide plans communicated during an interview. With high cut-off scores the specif icity of the SSRS became satisfactory, but the sensitivity dropped below 32 %. Internal consistency of the anamnestic history of the SSRS was low, whic h suggests that anamnestic risk factors for suicide in schizophrenia are mu ltifactorial. Internal consistency of the interview-based items was high, a nd present state risk factors seemed to consist of two separate factors, de pression-anxiety and irritability. Conclusions: The SSRS may be clinically useful in identifying schizophrenic patients with a particularly high risk for suicide. However, the SSRS seems not to be a practical screening instru ment for suicide risk in schizophrenia, and it is probably impossible to co nstruct a suicide risk scale with both high sensitivity and high specificit y in this disorder. (C) 2001 Elsevier Science B.V. All rights reserved.