The Mental Implications of Sex Chromosome Aberrations

Abstract

I have chosen as the subject for my Blake Marsh Lecture the influence of sex chromosome aberrations on intelligence, mental health and social adjustment. This subject provides a fascinating example of how a branch of research, beginning in the field of mental retardation, arrived at discoveries which proved to be of significance to quite other fields of psychiatry. Ten years ago we learned that sex-chromatin-positive males, that is, males with additional X chromosomes, at least in some cell lines, were more often encountered among the intellectually retarded than among the average population of males. Shortly after this we learned that the same was true of women with double Barr bodies, that is, women with more than the usual two X chromosomes, at least in some cell lines. Today we have facts showing that an abnormal sex chromosome complement may have an unfavourable effect on mental health, and this in several different ways; thus we know that it may contribute to the development of functional psychoses, and may even influence such a complex variable of behaviour as our ability to adapt ourselves to the laws of the community. Myself, I am convinced that study of aberrations in the sex chromosomes will prove to have a radical effect on large sections of psychiatric thinking.