J Korean Neuropsychiatr Assoc.  2009 Nov;48(6):496-501.

The Differences of 2nd to 4th Digit Length Ratio between Schizophrenia Patients and Normal Controls

• Cho HW
• Chae JH
• Lee YS

Abstract

OBJECTIVES
The length ratio of the second to the fourth finger (2D : 4D) is a known indirect measure of prenatal sex hormone exposure. Sex hormones influence brain development through structural and epigenetic modifications of neurons. We examined the 2D : 4D in schizophrenia patients and normal controls to investigate the relationship between prenatal sex hormone exposure and the genesis of schizophrenia.
METHODS
The participants were 187 schizophrenia patients (94 male, 93 female) and 190 normal controls (95 male, 95 female). We determined handedness via the Edinburgh Handedness Inventory and age of onset of schizophrenia via clinical records or directly questioning the patients. We measure digit length using vernier caliper and performed T-tests, ANOVA, and ANCOVA to analyze the data.
RESULTS
There were no significant 2D : 4D differences between schizophrenic participants and normal controls. Also, there was no significant correlation between the 2D : 4D and the age of onset of schizophrenia. Among the controls, the 2D : 4D was significantly higher (more "feminized") in females than in males (F=4.937, p=.027). But, there were no significant 2D : 4D sex differences among the schizophrenia patients (F=3.429, p=.066).
CONCLUSION
These results imply that sex hormone changes during fetal development might play some role in the development of schizophrenia.

Keyword

Sex hormones; 2D : 4D; Schizophrenia

MeSH Terms

Age of Onset
Brain
Epigenomics
Female
Fetal Development
Fingers
Functional Laterality
Gonadal Steroid Hormones
Humans
Male
Neurons
Schizophrenia
Sex Characteristics
Gonadal Steroid Hormones