Investigation of second to fourth finger length ratio (2D:4D) in schizophrenia patients

Correspondence: Faruk Kilic, Suleyman Demirel University, Faculty of Medicine, Department of Psychiatry, Isparta Turkey Phone: +90 246 211 93 35 E-mail: drfarukk33@hotmail.com Received: August 15, 2019; Revised: September 23, 2019; Accepted: October 18, 2019 ABSTRACT Objective: Schizophrenia is a significant burden for the patient and causes great costs for society. The etiology of schizophrenia, which is known to be a neurodevelopmental disorder, has not been fully elucidated. Differences in prenatal gonadal hormones have been suggested to play a role in the pathogenesis of schizophrenia. An easy way to evaluate a biomarker that gives insight about prenatal androgen is the second to fourth digit ratio (2D:4D) of the hand. In this study, we aimed to compare the 2D:4D ratio of schizophrenia patients to healthy controls and to investigate the relationship with positive and negative symptoms. Method: Seventy-six patients with schizophrenia and 67 healthy controls were included in the study. Finger lengths were measured from the proximal finger crease to the tip using a digital vernier caliper with a precision of 0.01 mm. The Scale for the Assessment of Positive Symptoms (SAPS) and the Scale for the Assessment of Negative Symptoms (SANS) were used to evaluate the symptoms of schizophrenia. Results: While the left 2D:4D ratio of the patients with schizophrenia was not different from the controls’, the right 2D:4D ratio was significantly lower. The correlation between finger lengths and the SAPS and SANS scores by gender showed a negative correlation of the left and right 2D:4D ratio with the SANS scores in female patients, while the SANS scores were found to be positively correlated with the right 2D:4D ratio in men. Conclusion: The findings of our study support the view that the right 2D:4D ratio may be an indicator for schizophrenia.