Personality traits of 47,XYY and 47,XXY males found among juvenile delinquents.

The mental features of nine 47,XYY males and six 47,XXY males found among Japanese juvenile delinquents were examined. The results of intelligence tests suggested a slight impairment among 47,XYY and 47,XXY males. The psychiatric interviews and the psychological tests revealed that 47,XYY males had a high activity level while 47,XXY males had a low one. Analyses of the offense type and psychophysiological features supported these findings. As the activity level is considered to be largely determined genetically, the extra Y is suspected to be responsible for the high activity level and the extra X in males to be responsible for the low activity level.