Features preceding diagnosis of bipolar versus major depressive disorders

Abstract Background Better and earlier predictive differentiation of bipolar (BD) vs. unipolar major depressive disorder (UD) diagnoses should improve long-term clinical planning. Methods We reviewed randomly selected clinical records of 334 adults diagnosed with DSM-IV-TR BD-I ( n =109), BD-II ( n =106), and UD ( n =119) and compared features preceding major affective episodes or diagnoses, using bivariate, multivariate, and Bayesian methods. Results We identified antecedents selectively associated with later BD vs. UD in 52.6% vs. 31.1% of subjects in childhood, starting at age 7.4 years, and 60.0% vs. 32.8% in adolescence, with far more features in BD than UD cases (10.3 vs. 4.64/100 person-years; p male sex > family BD-history > cyclothymic or hyperthymic temperament > antecedents/person-year. Nonaffective (anxiety, eating, or substance-use) disorders preceded BD vs. UD in 41.4% vs. 28.6% of subjects ( p =0.02). By ROC analysis, differential prediction of BD vs. UD was optimal with any ≥3 factors/person. Limitations The validity and timing of antecedent events and factors identified retrospectively from clinical records could not be verified independently, but information was recorded systematically and consistently by a single mood-disorder expert prior to diagnosis, and extracted by two independent observers. Comment Early clinical features distinguished later BD from UD, often by years. Such prediction should improve treatment-planning and limit risk of mood-switching.