Aggressive Behaviour, Mental Sub-normality and the XYY Male

  title={Aggressive Behaviour, Mental Sub-normality and the XYY Male},
  author={Patricia A. Jacobs and Muriel Brunton and MARIE M. Melville and Robert P. Brittain and W. M. F. McClemont},
IT is well known that 1 per cent of males in institutions for the mentally sub-normal are chromatin-positive and that the majority of these have an XXY sex chromosome constitution1. In 1963 Forssman and Hambert2 reported on a survey of the nuclear sex of 760 male patients in three Swedish institutions for criminal and ‘hard-to-manage’ males of sub-normal intelligence. They found 2 per cent to be chromatin positive, but the chromosome constitution of these patients was not reported. Casey… 

Psychopathy, Mental Deficiency, Aggressiveness and the XYY Syndrome

Preliminary findings are reported from a survey in a comparable population in the United States of mentally sub-normal male patients with “dangerous, violent or criminal propensities” found that seven of 197 inmates had an XYY sex chromosome constitution.

an XYY complement . normal males and males with Testosterone excretion rates in

The incidence of males with an XYY chromosome complement in a maximum security hospital was found to be 3% (Jacobs et al., 1965). These males were exceptionally tall, and it was found that 1 in 3 of

Testosterone excretion rates in normal males and males with an XYY complement.

The incidence of males with an XYY chromosome complement in a maximum security hospital was found to be 3% (Jacobs et al., 1965). These males were exceptionally tall, and it was found that 1 in 3 of

The Mental Implications of Sex Chromosome Aberrations

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

Chromosome errors in men with antisocial behavior. Comparison of selected men with Klinefelter's syndrome and XYY chromosome pattern.

A wide spectrum of criminal offenses and psychopathology, including psychosis, was manifested in both groups, and the Klinefelter males of this series displayed a mean intelligence quotient of 80 as opposed to 84 for the 47,XYY males.

Criminality and antisocial behaviour in unselected men with sex chromosome abnormalities

XYY males showed a significantly higher frequency of antisocial behaviour in adolescence and adulthood and of criminal convictions than the controls, but multiple regression analysis showed this to be mediated mainly through lowered intelligence.

Criminal Behaviour and the XYY Male

The most remarkable finding in the completed survey was the discovery among 315 men of nine patients with an XYY sex chromosome constitution, and their behaviour has now been closely studied.

Double Barr Bodies in Women in Mental Hospitals

It is not yet clear whether mentally defective women also contain an unusually large number with the XO constitution, but it is shown that mild mental deficiency is a common accompaniment of an XYY constitution in males.

Males with an XYY sex chromosome complement.

  • W. Brown
  • Medicine
    Journal of medical genetics
  • 1968
There exist serious imperfections in knowledge of the range of phenotypes that may be linked with this abnormal chromosome complement, and it is by no means certain that impaired testicular descent was merely a chance association with the XYY complement in some of the cases described in this first phase.

Childhood of males with the XYY syndrome

An investigation of the childhood of 20 adult males and 2 boys with the XYY syndrome, ranging in age from 6 to 58 years at the time of diagnosis, indicated that truancy, vagabondage, impulsiveness, and difficulties at school and in establishing contact with people were more frequent among patients with karyotype 47,XYY.



An XYY man with progeny indicating familial tendency to non-disjunction.

This case is the first XYY male on record and was it not for mongolism and other anomalies among his progeny he would have escaped the cytologist's curiosity, underscoring the advisability of extending chromosome study to relatives of patients with odd karyotypes.

XYY genotype. Report of a case in a male.