THE CRIMINALITY OF NONINSTITUTIONALIZED MENTALLY-RETARDED PERSONS - EVIDENCE FROM A BIRTH COHORT FOLLOWED TO AGE 30

This study examines the criminality of noninstitutionalized mentally r etarded (NIMR) men and women in a Swedish birth cohort composed of 15, 117 participants followed from before birth to age 30. NIMR participan ts were compared with participants who had never been placed in a spec ial class or in an institution for the mentally retarded or admitted t o a psychiatric ward (NMR). NIMR participants were more likely than NM R participants to have been convicted for a criminal offense before ag e 30 and for a violent offense. NIMR offenders had been convicted, on average, for the same number of offenses as NMR offenders. Among the N IMR offenders, 71% of men and only 43% were first convicted before the age of 18. For both NIMR men and women, childhood conduct problems we re found to be associated with adult criminality.