The relationship of predominant polarity with cognitive functions in patients with bipolar disorder in remission

Objective: In our study, it is aimed to elucidate the relationship of the predominant polarity in bipolar disorder with other clinical features, sociodemographic characteristics and cognitive dysfunction. Materials and methods: Patients with bipolar disorder in remission (n=84) and healthy control group volunteers (n=27) participated in the study. Patients were divided into 3 subgroups according to their predominant polarity characteristics: manic predominant polarity (n=31), depressive predominant polarity (n=25), and undetermined predominant polarity (n=28). Structured Clinical Interview for DSM-5 Disorders-Clinician Version (SCID-5/CV), (WAIS-R)-Vocabulary Subtest, Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale, Young Mania Rating Scale were administered to the volunteers. Those who met the criteria were included in the study. Rey's Auditory Verbal Learning Test (RAVLT), Trail Making Test (TMT), Stroop Test, WMS-R Visual Reproduction Subtest, Controlled Oral Word Association Test (COWAT), Auditory Consonant Trigrams Test (ACT), Reading the Mind in the Eyes Test (RMET), Hinting Test (HT), Wisconsin Card Sorting Test (WCST), and Conners Continuous Performance Test (CCPT) were administered to the participants. Results: Prolongation in Stroop C duration and Stroop interference and a decrease in the RAVLT, in the number of words recalled and remembered late were found in each of the predominant polarity groups compared to the Healthy Control (HC) group. Although impairment in global cognition, verbal memory and learning was demonstrated for each of the predominant polarity groups compared to the HC group, impairment in these domains could not be associated with the predominant polarity. In the Manic Predominant Polarity (MPP) group compared to the HC group, worse performance was observed in ACT, COWAT, social cognition tests, WCST, CPT correct target section and a prolongation in TMT-A. Compared to the Depressive Predominant Polarity (DPP), the MPP group showed a decrease in performance in COWAT and social cognition tests. MPP and Undetermined Predominant Polarity (UPP) groups showed deterioration in processing speed compared to HC. In addition, the MPP group showed impairment in working memory and attention compared to HC group. In the domain of problem-solving and reasoning, deterioration was found in the MPP group compared to the HC and UPP groups, and in the DDP group compared to only HC group. When the relationship between cognitive functions and the number and characteristics of episodes in Bipolar Disorder (BD) was evaluated, it was found that processing speed, global cognition, visual copying scores, WCST perseverative error, CPT correct target number, TMT- A and B durations were associated with both the total number of episodes and the number of manic episodes. In BD, problem-solving/reasoning, visual memory/learning, working memory, TMT B-A durations, ACT, COWAT, visual recall, social cognition tests scores, WCST correct and error numbers were only found to be associated with the number of manic episodes. Conclusion: Although the MPP group was the polarity group with more cognitive impairment, it performed worse on the verbal fluency and social cognition tests compared to the DDP group. In addition to demonstrating the relationship between the MPP group and cognitive dysfunction, cognitive disorders were found to be associated with the total number of episodes and the number of manic episodes in our study. Long-term prospective follow-up studies are needed to elucidate this relationship in the context of causality. Keywords: Bipolar Disorder, Cognitive Function, Predominant Polarity