Cognitive performance in older-age bipolar disorder: Investigating psychiatric characteristics, cardiovascular burden and psychotropic medication

Objective: This study aimed to explore a large range of candidate determinants of cognitive performance in older-age bipolar disorder (OABD). Methods: A cross-sectional study was performed in 172 BD patients aged ≥50 years. Demographics, psychiatric characteristics and psychotropic medication use were collected using self-report questionnaires and structured interviews. The presence of cardiovascular risk factors was determined by combining information from structured interviews, physical examination and laboratory assessments. Cognitive performance was investigated by an extensive neuropsychological assessment of 13 tests, covering the domains of attention, learning/ memory, verbal fluency and executive functioning. The average of 13 neuropsychological test Z-scores resulted in a composite cognitive score. A linear multiple regression model was created using forward selection with the composite cognitive score as outcome variable. Domain cognitive scores were used as secondary outcome variables. Results: The final multivariable model (N = 125), which controlled for age and education level, included number of depressive episodes, number of (hypo)manic episodes, late onset, five or more psychiatric admissions, lifetime smoking, metabolic syndrome and current use of benzodiazepines. Together, these determinants explained 43.0% of the variance in composite cognitive score. Late onset and number of depressive episodes were significantly related to better cognitive performance whereas five or more psychiatric admissions and benzodiazepine use were significantly related to worse cognitive performance. Conclusion: Psychiatric characteristics, cardiovascular risk and benzodiazepine use are related to cognitive performance in OABD. Cognitive variability in OABD thus seems multifactorial. Strategies aimed at improving cognition in BD should include cardiovascular risk management and minimizing benzodiazepine use