Cognitive Functions of Bipolar Disorder Patients in Remission on Monotherapy: A Follow-Up Study

Objective: Multiple sectional studies indicate that the cognitive functions of bipolar disorder (BD) patients in remission are damaged. These studies also suggest that cognitive functions get worse over time. Although the results are inconsistent, there are limited follow-up studies that reveal any contradictory results. Interestingly, there have been major difficulties in the interpretation related to this subject. In particular, scarcity of longitudinal studies and not eliminating the role of multidrug side effects on cognitive functions are just a few. Due to these aforementioned limitations, the longitudinal course of cognitive functions and their sectional differences were investigated in BD patients that underwent remission with monotherapy in this study. Methods: In this study, the cognitive functions (premorbid IQ, attention, executive functions, memory, visual-spatial skills, and psychomotor speed) of BD patients (n=27) in remission and on monotherapy for at least 1 month were assessed at baseline and at an 18 (6-77) month follow-up period and compared to healthy controls (n=35). Results: The BD group's performance was worse than those of the control group on tests that evaluated attention, executive functions including concept formation, mental flexibility, response inhibition, set shifting, and reasoning, verbal memory, and psychomotor speed. On the other hand, the BD group showed no significant differences at baseline and follow-up examinations. Conclusion: All cognitive functions of BD patients on monotherapy remained stable during the follow-up. This suggests that this group might be a sub-group of BD with good prognosis, and monotherapy may not be harmful on cognitive functions. On the other hand, it needs longer time to detect cognitive dysfunctions.