Second to fourth digit ratio and cognitive functioning in bipolar disorder.

Objective: Bipolar disorder (BD) involves complex mood, neuropsychological, immunological, and physiological changes, with cognitive impairment persisting even during remission. Our study investigated the relationship between the second-to-fourth digit ratio (2D:4D) and cognitive function in BD patients.

Methods: This cross-sectional study, which included 47 BD patients in remission for = 6 months and 47 healthy volunteers, was designed to thoroughly determine the relationship between the 2D:4D and cognitive function in BD. The Stroop Test, the Wisconsin Card Sorting Test, and the Trail Making Test A and B forms were administered to all participants. The same researcher measured the 2D:4D ratio using a digital caliper to ensure consistency and accuracy.

Results: The left 2D:4D ratio was significantly higher in the patient group than the control group. There were also significant differences in all test scores between groups, with the BD group scoring higher and being more unsuccessful. We also observed a weak negative correlation between completion time of Form A of the Trail Making Test and right-hand 2D:4D finger ratio in the BD group.

Conclusions: Our findings have significant implications, revealing a marked difference in the 2D:4D of BD patients compared to healthy controls and a decline in cognitive function even during remission.