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Updated: Jun 17, 2026

Handwriting Analysis Indicates Spontaneous Dyskinesias in Neuroleptic Naïve Adolescents at High Risk for Psychosis
Published on: November 21, 2013
Increased ratio of 2nd to 4th digit (2D:4D) in schizophrenia
Simon Lowes Collinson1, Matthew Lim, Jia Hui Chaw
1Department of Psychology, National University of Singapore, 117570, Singapore. psycsl@nus.edu.sg
Abstract:
Sex differences in the onset, epidemiology, clinical presentation and neuropathology of schizophrenia suggest that sexual dimorphism in brain development may be relevant to pathogenesis. Sex hormones, in particular testosterone, are considered to be crucial in brain development, but few investigations have examined the potential role of prenatal testosterone in schizophrenia. In this study, we examined a retrospective marker of prenatal testosterone release - 2D:4D finger length ratio (2D:4D), the relative length of 2nd to 4th digit, in 64 Asian patients with schizophrenia and 64 sex-matched controls. No significant difference in mean finger lengths was present, however 2D:4D ratio was significantly different between patients and controls. The effect was primarily seen in males consistent with a 'less masculinised' pattern and hypotheses suggesting that schizophrenia may be associated with an abnormality in prenatal circulating testosterone.
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