The ratio of the lengths of the index finger and the ring finger in men may be an effective predictor of schizophrenia, scientists have found.
Turkish researchers found that the ratio of the lengths of the second digit (2D) and fourth digit (4D) may be predictive of a variety of disorders related to disturbed hormonal balance in males.
When the index finger is shorter than the ring finger, this results in a small 2D:4D ratio, pointing to a high exposure to testosterone in the uterus, researchers said.
There were significant differences between schizophrenia and control groups concerning the ratio of the lengths of the second digit to the fourth digit, as well as its asymmetry, in both hands.
"Asymmetry index showed moderate discriminatory power and, therefore asymmetry index has a potential utility as a diagnostic test in determining the presence of schizophrenia," said Dr Taner Oznur from Gulhane Military Medical Faculty, Department of Psychiatry, Ankara.
The study was published in the journal Clinical Anatomy.