<p>The subjects were 130 male prisoners in Swedish jails were examined by SCID and the diagnoses given in terms of DSM-IV. The most common mental disorder was drug abuse. On Axis II several personality disorders were diagnosed. Personality assessments were made by KSP. High scores were mainly found for e.g. impulsiveness, sensation seeking, aggression and low scores in socialisation.</p><p>MAO assays were performed in 99 male criminal offenders and in 60 non-criminal volunteers. Offenders had lower MAO activity than controls also with the confounding factor smoking under control. It is proposed that platelet MAO is linked to personality traits, which can predispose for criminality. </p><p>For testing the existence of combinations of vulnerability factors, a configuration frequency analysis (CFA) was used. The criteria which formed the basis for the subgrouping were; MAO activity below or above –0.5 SD of the mean (L and H), the presence or absence of an Axis I disorder (= drug abuse) (Y/N), the presence or absence of an Axis II disorder (Y/N), or the presence or absence of an Axis I and II disorder (Y/N). In this way eight subgroups were formed. Two significant "types" were found among the criminals: One was characterised by low platelet MAO activity, Cluster B personality diagnosis as well as Drug Abuse Disorder diagnosis (LYY); and the other by a pattern of normal platelet MAO activity, no Cluster B personality disorder, and no Drug Disorder diagnosis (HNN). Also two "antitypes", occurring less frequent than expected, were identified; LYN and LNY. Thus, the aggregation of certain risk factors in the same individual has been shown to contribute to the development of criminal behaviour.</p><p>The subgroups HNN, LYN, LNY and LYY were then analysed for a variety of criminological factors. There was a difference in mean age between the subgroups, the HNN being lowest. Economical crimes were more common at an early criminal debut and crimes involving violence at an adult debut. The HNN subgroup had a lower number of crimes and times spent in jail than the other subgroups. More than 50% of the clients in all groups had previously been sentenced to Reformatory.</p>

The subjects were 130 male prisoners in Swedish jails were examined by SCID and the diagnoses given in terms of DSM-IV. The most common mental disorder was drug abuse. On Axis II several personality disorders were diagnosed. Personality assessments were made by KSP. High scores were mainly found for e.g. impulsiveness, sensation seeking, aggression and low scores in socialisation. MAO assays were performed in 99 male criminal offenders and in 60 non-criminal volunteers. Offenders had lower MAO activity than controls also with the confounding factor smoking under control. It is proposed that platelet MAO is linked to personality traits, which can predispose for criminality. For testing the existence of combinations of vulnerability factors, a configuration frequency analysis (CFA) was used. The criteria which formed the basis for the subgrouping were; MAO activity below or above –0.5 SD of the mean (L and H), the presence or absence of an Axis I disorder (= drug abuse) (Y/N), the presence or absence of an Axis II disorder (Y/N), or the presence or absence of an Axis I and II disorder (Y/N). In this way eight subgroups were formed. Two significant "types" were found among the criminals: One was characterised by low platelet MAO activity, Cluster B personality diagnosis as well as Drug Abuse Disorder diagnosis (LYY); and the other by a pattern of normal platelet MAO activity, no Cluster B personality disorder, and no Drug Disorder diagnosis (HNN). Also two "antitypes", occurring less frequent than expected, were identified; LYN and LNY. Thus, the aggregation of certain risk factors in the same individual has been shown to contribute to the development of criminal behaviour. The subgroups HNN, LYN, LNY and LYY were then analysed for a variety of criminological factors. There was a difference in mean age between the subgroups, the HNN being lowest. Economical crimes were more common at an early criminal debut and crimes involving violence at an adult debut. The HNN subgroup had a lower number of crimes and times spent in jail than the other subgroups. More than 50% of the clients in all groups had previously been sentenced to Reformatory.