March 1972

Evidence Linking an Extra Y Chromosome to Sociopathic Behavior

Author Affiliations

Syracuse, NY
From the Genetic and Endocrine Unit, Department of Pediatrics, State University of New York, Upstate Medical Center, Syracuse, NY.

Arch Gen Psychiatry. 1972;26(3):220-222. doi:10.1001/archpsyc.1972.01750210028005

Two lines of evidence have emerged from a study of XYY males in the literature that tend to refute the argument that aggressive behavior in these individuals is a myth promoted by the mass media. First, there is a higher incidence (1.8% to 12%) of XYY males in institutions than in the general population (0.14% to 0.38%) as determined from newborn surveys. Secondly, a psychological evaluation of a group of XYY men characterized them as passive, dependent on others, and incapable of controlling their impulses. The extra Y chromosome does have an apparent effect on behavior, and should be considered a factor in assessing a defendant's responsibility in a court of law.