Objective: To investigate the potential association between the ratio of the second digit length to the fourth digit length (2D:4D) and schizophrenia, to provide evidence regarding the pathogenesis of schizophrenia.
Methods: In this study, we enrolled 843 patients with schizophrenia (387 men and 456 women), all of whom met the diagnostic criteria of the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), and 1050 normal healthy controls (477 men and 573 women). The digit lengths of both hands were measured in all subjects and the 2D:4D ratio was analyzed.
Results: In the healthy controls, the 2D:4D ratio was sexually dimorphic, with a larger value in women than in men. In addition, the 2D:4D ratio in the schizophrenia patients was significantly larger than in the healthy controls. The 2D:4D ratio of the right hand was more sexually dimorphic than the left hand. Furthermore, the difference in 2D:4D ratios between the male patients and male controls was significantly larger than in their female counterparts.
Conclusions: By analyzing the 2D:4D ratio and considering alternative factors related to schizophrenia, our findings support the hypothesis that there are abnormal cerebral conditions in schizophrenia patients.
Keywords: 2D:4D; Minor physical anomaly; digit ratio; pathogenesis; schizophrenia; surface feature.