Abstract
In a study of 41 inpatient boys with psychiatric disorders, it was found that this group had significantly increased length of the long arm of the Y chromosome (Yq+) as compared to a normal control group. The length of the Y chromosome in the inpatient group correlated with psychiatric symptom severity, hyperactivity, parental psychopathology and paternal alcoholism. A further study of minor chromosomal variants in 56 inpatient boys and girls revealed no differences in individual or pooled variants in the patient group, as compared to the control group. However, those in the patient group with one or more variants showed more severe psychiatric and other psychosocial symptoms than those in the group without variants. Those who had both longer Y chromosomes and a minor chromosomal variant had more severe psychiatric symptom severity.