The association between psychotropic medications and cognitive functioning in bipolar disorder

Many individuals with bipolar disorder have decreased levels of cognitive functioning even when in a euthymic mood state. Persons with bipolar disorder are usually treated with psychotropic agents, but the effects of these medications on their cognitive functioning have not been extensively studied.

A total of 567 people with bipolar disorder were assessed on a cognitive battery, the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and Trail Making Test, part A (Trails A) and Letter-Number Sequencing. The machine-learning tool of cross-fit partialing-out least absolute shrinkage and selection operator (LASSO) regression was used to examine the independent association between the cognitive test scores and receipt of individual psychotropic medications considering relevant demographic and clinical covariates. Ordered logistic regression models were employed to examine the effects of medication dosage on the cognitive scores.

We found that 3 medications, ziprasidone, benztropine, and clonazepam, were independently associated with significantly reduced cognitive scores compared with individuals not receiving these medications. Benztropine showed a significant dose-related relationship with all of the cognitive measures. Reduced memory and psychomotor speed were the domains most associated with receipt of these medications.

Prescribers may consider limiting the administration of the medications which can affect cognitive functioning. Interventions should be further developed for people with bipolar disorder to improve their cognitive functioning and quality of life.