Objectives: The purpose of this study was to investigate whether the presence of comorbid personality disorder influences the course of bipolar illness.
Methods: Fifty-two euthymic male bipolar I out-patients were assessed using the Structured Clinical Interview for DSM-III-R Personality Disorders (SCID II). Bipolar patients with an axis II diagnosis were compared with those without an axis II diagnosis on retrospectively obtained demographic, clinical and course of illness variables.
Results: Thirty-eight percent of the bipolar patients met criteria for an axis II diagnosis. Two (4%) met criteria for (only) a Cluster A disorder, four (8%) for (only) a Cluster B, and six (12%) for (only) a Cluster C disorder. One (2%) bipolar patient met criteria a disorder in both Clusters A and B, and one (2%) for a disorder in Clusters B and C. Five (10%) met criteria for at least one disorder in Clusters A and C, and one met criteria for disorders in Clusters A, B, and C. The presence of a personality disorder was significantly associated with a lower rate of current employment, a higher number of currently prescribed psychiatric medications, and a higher incidence of a history of both alcohol and substance use disorders compared with the bipolar patients without axis II pathology.
Conclusions: Our results extend previous findings of an association between comorbid personality disorder in bipolar I patients and factors that suggest a more difficult course of bipolar illness.