Predictors and prevalence of bipolar disorders in patients with a major depressive disorder

Abstract

Introduction Onset of bipolar disorder (BD) involves a major depressive episode (MDE) in approximately half of type-I (BD-I) patients and three-quarters of those diagnosed with type-II (BD-II). Aim To detect the soft signs and the predictors of BD in patients with a MDE. Participants and methods A sample of 500 patients was solicited fulfilling the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) diagnostic criteria for a current MDE. Patients were given the HCL-32-R2 questionnaire to assess the presence of manic/hypomanic symptoms; those scoring less than 14 were considered bipolar. We also examined whether demographics, psychiatric history, clinical characteristics, and the incidence of comorbid conditions differed significantly between patients with BD and unipolar disorder. Results A number of factors were highly predictive of bipolarity, including age at illness onset, family history of bipolarity, seasonality, mixed state, manic switch, mood irritability, and mood reactivity. Of the comorbidities examined, thyroid disorders, cardiovascular disorders, generalized anxiety disorder, presence of psychotic features, and borderline personality disorder occurred at a higher rate in patients with BDs than in those with unipolar disorders. Conclusion A number of factors in the patient’s psychiatric history as well as clinical aspects of the episode itself may signal an increased likelihood of bipolarity.