Personality disorders and completed suicide: A methodological and conceptual review

Case-based and cohort studies on personality disorders (PD) and completed suicide are reviewed. Approximately 30-40% of suicides are committed by individuals with PD; borderline, antisocial, and possibly avoidant and schizoid PD increase risk. Although longitudinal, or cohort, designs are increasingly popular in psychopathology research, they have tended to yield small, nonrepresentative samples of suicides. Moreover, case-based studies have identified putative risk factors that cohort studies have overlooked. Only the case-control design can identify risk factors in a representative sample of suicides. Ideally, future use of that design would examine more rigorously whether avoidant PD, schizoid PD, and unusual combinations of personality traits increase suicide risk.