Cognitive Impairment Among Female Patients With Bipolar Disorder According to the Polarity of the First Episode

Background: Bipolar disorder (BD) is a severe, recurrent mood disorder with alternating episodes and persistent cognitive deficits. There are sex differences in episode type, onset age, cognitive dysfunction, and other aspects. Female patients have distinct cognitive impairments. Understanding sex differences is important to assess the condition and optimize treatment. This study investigated the characteristics of cognitive impairment in female patients with BD based on first-episode polarity (manic/hypomanic vs. depressive) and identified associated clinical risk factors. Methods: This cross-sectional study enrolled 61 female BD patients (20 with manic/hypomanic onset, 41 with depressive-onset) and 31 healthy controls. Cognitive domains were assessed using the Wisconsin Card Sorting Test (WCST), the Continuous Performance Test (CPT), and the Digit Span Test (DST). Group comparisons and multivariate regression analyses were conducted to evaluate cognitive patterns and clinical correlates. Results: (a) Both the manic/hypomanic-onset and the depressive-onset groups showed significantly worse scores compared with the healthy controls; (b) the manic/hypomanic-onset group demonstrated significantly higher scores than the depressive-onset group; and (c) a history of exposure to mental stimuli was associated with reduced patients’ executive function. Additionally, a lower educational level and an early onset were potential risk factors for impaired memory functions. Conclusions: Female patients with BDs exhibited cognitive impairments that varied according to first-episode polarity. Those with manic/hypomanic onset exhibited less severe cognitive impairment than those with depressive-onset. Lower educational attainment and earlier disease onset were identified as independent risk factors for cognitive dysfunction.