Cognition in older age bipolar disorder: An analysis of archival data across the globe

BACKGROUND: Cognitive deficits in bipolar disorder (BD) impact functioning and are main contributors to disability in older age BD (OABD). We investigated the difference between OABD and age-comparable healthy comparison (HC) participants and, among those with BD, the associations between age, global cognitive performance, symptom severity and functioning using a large, cross-sectional, archival dataset harmonized from 7 international OABD studies.

METHODS: Data from the Global Aging and Geriatric Experiments in Bipolar Disorder (GAGE-BD) database, spanning various standardized measures of cognition, functioning and clinical characteristics, were analyzed. The sample included 662 euthymic to mildly symptomatic participants aged minimum 50years (509 BD, 153 HC), able to undergo extensive cognitive testing. Linear mixed models estimated associations between diagnosis and global cognitive performance (g-score, harmonized across studies), and within OABD between g-score and severity of mania and depressive symptoms, duration of illness and lithium use and of global functioning.

RESULTS: After adjustment for study cohort, age, gender and employment status, there was no significant difference in g-score between OABD and HC, while a significant interaction emerged between employment status and diagnostic group (better global cognition associated with working) in BD. Within OABD, better g-scores were associated with fewer manic symptoms, higher education and better functioning.

LIMITATIONS: Cross-sectional design and loss of granularity due to harmonization.

CONCLUSION: More research is needed to understand heterogenous longitudinal patterns of cognitive change in BD and understand whether particular cognitive domains might be affected in OABD in order to develop new therapeutic efforts for cognitive dysfunction OABD.