Predominant polarity in bipolar disorder: Findings from the bipolar disorder course and outcome study from India (BiD-CoIN study)

Aim: This cross-sectional study aimed to assess the predominant polarity (PP) in patients with bipolar disorder (BD) and the factors associated with PP. Methodology: For this study, 773 participants with at least 10 years of illness, were recruited from 14 centres, were evaluated using the National Institute of Mental Health- Retrospective Life Charts to assess the course of illness and PP was determined by both Barcelona proposal and the Harvard Index. Results: According to Barcelona proposal for PP, 20.6% of the patients belonged to depressive PP, 45.8% belonged to manic PP and 33.6% belonged to indeterminate polarity. According to Harvard index of PP, 31.6% of the patients belonged to depressive PP, 56.1% belonged to manic polarity and 12.3% of the patients could not be categorized into any of these categories and hence, were considered to have indeterminate polarity. Those with depressive PP were more often having BD-II, had later age of onset, spent more time in episodes, had higher residual depressive symptoms, had lower residual manic symptoms, more often had depression as the first lifetime episode, and less often had at least one psychotic episode. Conclusion: In the Indian subcontinent, although the prevalence of PP is influenced by the definition used, the most common PP is that of mania.