Comparison of Neuropsychological Functions in Euthymic Bipolar I Disorder Patients and General Population

Abstract

Background: Bipolar disorder is associated with persistent deficits in neuropsychological functions, which may be considered as an endophenotype. This study aimed to compare neuropsychological functions, including cognitive flexibility, inhibition, working memory, selective attention, and sustained attention in patients with bipolar I disorder in the euthymic phase and healthy individuals. Methods: In this causal-comparative study, 30 patients with bipolar I disorder in the euthymic phase and 30 healthy individuals, matched in terms of age and gender, were selected through purposive sampling. Neuropsychological assessments were conducted using computerized tools, including the Wisconsin (cognitive flexibility), Go/No-Go (inhibition), Wechsler and N-Back (working memory), Stroop (selective attention), and CPT (sustained attention). Data were analyzed using multivariate analysis of variance (MANOVA). Findings: The results revealed significant differences between the two groups in several indices. Patients with bipolar disorder exhibited poorer performance compared to the healthy group in cognitive flexibility (perseverative errors, correct responses, and other errors), inhibition (commission error score and percentage), N-Back working memory (omission, correct response count and percentage, mean response time, and standard deviation of response time), and selective attention (number of congruent and incongruent errors, incongruent omissions, and number of correct congruent and incongruent responses). No significant differences were observed in other subscales despite the poorer performance of patients. Conclusion: It appears that bipolar disorder impacts neuropsychological functions, and these deficits continue either persistently or selectively even during the euthymic phase. Our findings emphasized the importance of cognitive assessment and the consideration of neuropsychological rehabilitation interventions for these patients. © 2026, Isfahan University of Medical Sciences(IUMS). All rights reserved.