Clinical correlates of late‐onset versus early‐onset bipolar disorder in a global sample of older adults

Objectives Late‐onset bipolar disorder (LOBD) represents a significant subgroup of bipolar disorder (BD). However, knowledge for this group is mostly extrapolated from small studies in subjects with early/mixed age of illness onset. In this global sample of older adults with BD (OABD: ≥50 years old) we aim to characterize the sociodemographic and clinical presentation of LOBD (≥40 years at BD onset) compared to early‐onset BD (EOBD: 0.05). Late‐onset bipolar disorder was associated with higher endocrine comorbidities (odds ratio = 1.48, [95%CI = 1.0,12.1], p = 0.03). This difference did not remain significant when subjects with BD onset ≥50 years old were analyzed. Limitations This study is limited by the retrospective nature of the variable age of onset and the differences in evaluation methods across studies (partially overcame by harmonization processes). Conclusion The present analysis is in favor of the hypothesis that LOBD might represent a similar clinical phenotype as classic EOBD with respect to core BD symptomatology, functionality, and comorbid physical conditions. Large‐scale global collaboration to improve our understanding of BD across the lifespan is needed. Key points Knowledge of older age bipolar diosrder is mostly extrapolated from studies in subjects with early/mixed age of illness onset, with limited sample sizes. The Global Aging and Geriatric Experiments in Bipolar Disorder (GAGE‐BD) consortium provided international data to compare Late‐Onset BD versus early‐onset BD (EOBD). International sites (n = 14) provided data on patients over 50 years of age (n = 437) to assess depression, mania, functionality, and physical comorbidities. Late‐onset (n = 105) did not differ from Early‐onset (n = 332) subjects on depression, mania, global functioning, nor employment status (p > 0.05) and the results are in favor of supporting the hypothesis that late‐onset bipolar disorder (LOBD) might represent a similar clinical phenotype as classic EOBD.