Second fourth finger ratio (2D:4D) and cognitive functions in patients with bipolar disorder

The aim of the study is to examine the relationship between Bipolar Disorder (BPD) and 2:4 finger length ratio and cognitive functions. This study is a cross-sectional study conducted in the psychiatry outpatient clinic of Akdeniz University Hospital. The study included 47 BPD patients aged 18-65, aged between 18-65, who were diagnosed with BPD by two different doctors according to the DSM-5 diagnostic criteria, were in remission for at least 6 months, had no additional psychiatric or neurological diagnosis, and were literate. According to the DSM-5 diagnostic criteria, 47 healthy controls who did not have a psychiatric or neurological diagnosis in the past or at the time of enrollment were included in the study. Sociodemographic form developed by the researcher in the form of face-to-face questions and answers to all participants and structured in accordance with the purpose of the research, Stroop test (ST), Wisconsin card matching test (WCST), Tracking test A and B forms (IST A-B), Hamilton depression scale, Young mania scale was applied, 2nd and 4th finger lengths were measured with caliper. In our study, when the BPD and control groups were compared, a statistically significant difference was found in the ratio of left 2nd and 4th finger lengths. The BPB group performed ST, WCST, IST A and IST B forms statistically more unsuccessful than the control group. A statistically significant correlation was found between the finger ratios of the control group and the success of WCST, IST B form. An important finding in our study is the relationship between 2nd and 4th finger length ratios and BPD. This finding may help explain the etiology of BPD. Another important finding is that the 2nd and 4th finger length ratios of the control group were correlated with cognitive functions. 2nd and 4th finger ratios have been associated with intrauterine testosterone, estrogen and some genes in the literature. This shows that intrauterine testosterone and estrogen levels may be related to cognitive functions. This situation needs to be evaluated with future studies.