Risk factors for completed suicide in schizophrenia and other chronic psychotic disorders: A case–control study

Abstract

Objective Despite an increased risk for suicide among individuals diagnosed with psychotic disorders, risk factors for completed suicide remain largely unexamined in this population. Using a case–control design, this study aimed to investigate clinical and behavioural risk factors for suicide completion in schizophrenia and other chronic psychotic disorders. Method A total of 81 psychotic subjects were examined; of these, 45 died by suicide. Proxy-based interviews with, on average, 2 informants were conducted using the SCID I and II interviews and a series of personality trait assessments. Results Psychotic individuals at risk for suicide are most readily identified by the presence of depressive disorders NOS, moderate to severe psychotic symptoms and a family history of suicidal behaviour. They also exhibited fewer negative symptoms, had more comorbid diagnoses and, contrary to findings in other populations, we found that cluster A and C personality trait symptoms seem to have protective effects against suicide in schizophrenics and other chronic psychotic suicides. Conclusions Our study suggests that behavioural mediators of suicide risk, such as impulsive–aggressive behaviours, do not play a role in schizophrenic and chronic psychotic suicide. This is contrary to findings in other diagnostic groups, thus implying heterogeneity in predisposing mechanisms involved in suicide.