Age of onset and course and outcome of bipolar disorder: Findings from the bipolar disorder course and outcome study from India (BiD-CoIN study).

Background: There is limited data on subtyping of bipolar disorder (BD) based on age of onset (AOO) from developing countries. Aim: Accordingly this study aimed to compare the long-term course of bipolar disorder among patients with early onset (onset before 18 years) and later AOO (onset after 18 years). Methods: Using the data of the Bipolar Disorder Course and Outcome study from India (BiD-CoIN study), the study sample was divided into two groups and the groups were compared for the course of illness, predominant polarity, cognitive impairment, disability, and insight. Results: The study shows that compared to BD patients with later AOO, those with early AOO have a higher number of depressive and manic episodes, spend significantly lower time in episodes, have lower level of cognitive impairment, a higher proportion of them have history of relapse due to poor adherence, higher proportion have history of hospitalization, receiving electroconvulsive therapy (ECT), a higher prevalence of unipolar mania, predominant manic polarity, and receive higher mean dose of valproate. Conclusion: To conclude, this study suggests that age of onset of BD has impact on the course of illness in the form of more severe illness.