PSYCHOPATHY, PLATELET MAO ACTIVITY AND CRIMINALITY AMONG FORMER JUVENILE DELINQUENTS

Psychopathy-related personality traits as well as platelet monoamine o xidase (MAO) activity and criminality from the age of 15 years were st udied in a group of 68 male former juvenile delinquents and 32 control subjects. The former juvenile delinquents registered for crime as adu lts were found to have higher Psychopathy Check List (PCL) scores and lower platelet MAO activity than either juvenile delinquents who were not registered criminals from the age of 15 years or non-criminal cont rols. Although PCL scores and platelet MAO activity were unrelated, a configural frequency analysis showed a significant interaction. Indivi duals with PCL scores, low platelet MAO activity and persistent crimin al behaviour constituted a significant 'type'. Among the 27 former juv enile delinquents who developed persistent criminality, 21 subjects (7 8%) had PCL scores greater than 0 and low platelet MAO activity, while none of these persistent criminals were characterized by a combinatio n of zero PCL score and high platelet MAO activity.