Could the shortness in the digit ratio (2D:4D) of manic people with bipolar disorder be directly associated with criminal behavior?

Abstract The purpose of this study was to examine the relationship between 2D:4D digit ratio and aggression and impulsivity in manic patients (BP) with and without a history of criminal behavior. The study included a total of 106 participants, which encompassed 41 healthy individuals, 34 BP with a history of criminal behavior (CBP), and 31 BP who had not engaged in criminal activity (NCBP). All participants were administered a socio-demographic data form, the Buss-Perry Aggression Scale (BAQ), Barratt Impulsiveness Scale-11 (BIS-11), and the Young Mania Rating Scale (YMRS) for those with bipolar manic disorder and 2D:4D digit ratio measurement. The right hand 2D:4D finger ratios of BP included in the study were significantly lower compared to the control group, and that the right hand 2D:4D finger ratio was correlated with the duration of the illness. Moreover the BAQ scores of BP were higher compared to the control group. In CBP, both the right hand 2D:4D and left hand 2D:4D were significantly lower compared to the control group. Furthermore, the BIS-11 score and YMRS of CBP were significantly higher compared to NCBP.