Comorbid personality disorders in subjects with bipolar I disorder

Objective. The purpose of this study was to present the frequencies of personality disorders in a sample of bipolar I patients and to investigate whether the presence of comorbid personality disorders affect the course of bipolar illness.

Seventy euthymic bipolar I patients were assessed using the Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID II). Bipolar patients with comorbid personality disorder were compared with those of without personality disorder comorbidity on demographic and clinical variables.

Forty bipolar I patients (57%) had at least one comorbid personality disorder. The most common personality disorder cluster was cluster C (36%), followed by cluster B (17%) and cluster A (17%) personality disorders. The most prevalent personality disorder in the whole group was obsessive-compulsive personality disorder (21%). Patients with comorbid personality disorders had an earlier age of onset than those of without comorbidity.

Although the rates of comorbid personality disorders are high in bipolar I patients, the presence of comorbidity has no relevant impact on the course of bipolar I patients except for earlier age of onset of bipolar I disorder.