Age as a predictor of cognitive decline in bipolar disorder

Cognitive dysfunction is a core feature of bipolar disorder (BD) in both adult and geriatric patients. However, little is known about whether cognitive functioning declines at a faster rate in patients with BD, and there are conflicting reports regarding the relationship between age and cognitive functioning in this population. This cross-sectional study examined the relationship between age and cognitive functioning in patients with BD.

Patients with BD I (N = 113) and healthy adults (N = 64) ages 18-87 completed measures of processing speed, attention, executive functioning, verbal fluency, and clinical symptomatology. Groupwise comparisons were used to examine differences between patients and the comparison group and adult and geriatric BD cohorts. A series of linear regressions was conducted to examine the relationship of age and cognitive functioning and clinical variables and cognition.

Patients performed significantly worse than the comparison group on all neuropsychological measures. Age was a significant predictor of Trails A scores with older age associated with worse performance.

Older age was associated with poorer performance on Trails A in patients with BD but not healthy adults. These results are suggestive of greater dysfunction in processing speed with older age in patients with BD compared with a healthy comparison group. Because cognitive functioning is associated with community outcomes, these findings suggest a need for treatments targeting cognitive symptoms across the life span. Future research exploring neurobiologic evidence for neurodegenerative processes in BD will pave the way for potential therapeutic interventions.