Background: Schizophrenia and schizoaffective disorder are diagnostic categories that are particularly at risk for suicide. A number of risk factors have been proposed to play a role in vulnerability to suicide, but it is unclear whether these are specific to certain diagnostic groups at risk for suicide or generalizable across disorders. It remains to be better understood what differentiates schizophrenic from non-schizophrenic suicides and whether or not these two groups share a common suicide liability.
Methods: Five hundred and twenty seven consecutive suicides, 43 of whom met criteria for schizophrenia and schizoaffective disorder, were investigated by means of proxy-based interviews using structured diagnostic instruments and personality trait assessments.
Results: Compared to other suicides, we found that schizophrenic and schizoaffective suicides presented comparably elevated levels of impulsive aggressive traits. They also had comparable levels of family history of suicidal behaviour among first degree relatives. Overall, schizophrenics and schizoaffective suicides met criteria for fewer psychiatric disorders, and were less likely to meet criteria for more than one disorder. Compared to suicides without schizophrenia or schizoaffective disorders, lower levels depressive disorders, of current and lifetime comorbid alcohol abuse, and personality disorders were found within those suicides who met criteria schizophrenia and schizoaffective disorders.
Conclusions: Elevated levels of impulsive-aggressive personality traits, considered as indicative of an elevated risk for suicide in other diagnostic categories, are also found among schizophrenic and schizoaffective suicide completers. Elevated levels of impulsive aggressive behaviours may serve as a common liability to suicide across major psychopathological categories, including schizophrenia and schizoaffective disorder.