Personality disorders as predictors for the conversion from major depressive disorder to bipolar disorder: A prospective cohort study

Abstract

Studies suggest that personality disorders can predict mood disorders. The present study aims to assess whether personality traits in individuals with major depressive disorder (MDD) can predict the conversion to bipolar disorder (BD). This was a prospective cohort study conducted in two waves. In the first wave, 585 subjects were diagnosed with MDD; in the second wave, all of them were reevaluated in a three-year follow-up. Personality traits were evaluated, in the first phase, using the Millon Clinical Multiaxial Inventory (MCMI). MDD and BD diagnosis was performed by trained psychologists using a clinical structured interview based on diagnostics criteria of DSM IV, the Mini International Neuropsychiatric Interview, Plus version (MINI-PLUS). During the second wave, 468 individuals were reevaluated. Diagnostic conversion rate from MDD to BD was 12.4%. Higher mean scores in Antissocial, Borderline personality traits and in the sum of all Cluster B disorders were found among individuals who had converted to BD. In addition, individuals who converted to BD had lowest scores in obsessive-compulsive personality traits. Our findings suggest that Cluster B personality disorders can be considered as predictors of diagnostics conversion from MDD to BD. Also, it seems that obsessive-compulsive traits were lower among those individuals who have converted to BD.

Keywords

• Personality disorders
• Major depressive disorder
• Bipolar disorder
• Diagnostic conversion
• Cohort study