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.
In the study of 103 male patients diagnosed with schizophrenia and 100 matched healthy male individuals, researchers found that the 2D:4D ratio may be an effective predictor of schizophrenia.
"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.