Differences between juvenile offenders with and without intellectual disabilities in the importance of static and dynamic risk factors for recidivism

Background: Juvenile offenders with intellectual disability (ID) have been largely ignored in the literature of risk assessment, while they are overrepresented in the criminal justice system, and ID is a risk factor for juvenile delinquency and recidivism. The aim of this study was to examine whether there are differences between juvenile offenders with and without ID in the impact of risk factors for recidivism. Both the impact of static and dynamic risk factors were examined. Static risk factors were examined in the criminal history domain and dynamic risk factors were examined in the domains of family, school, use of free time, friends, alcohol/drugs, attitude, aggression and skills. This knowledge is important for both assessment and treatment of juvenile offenders with ID.

Method: The sample consisted of adolescents who appeared before the courts for a criminal act and for whom the Washington State Juvenile Court Assessment (WSJCA) was completed. The group of ID juvenile offenders (n = 102) consisted of juvenile offenders with a formal diagnosis of ID, which means a full scale IQ of less than 70, coupled with significant deficits in adaptive behaviour, with childhood onset. The juveniles of this group are special education students or they have a formal diagnosis of a special education need. The group without ID (n = 526), was a random sample of all juvenile offenders without a formal diagnosis of ID.

Results: No differences were found between juvenile offenders with and without ID in the impact of risk factors on recidivism in most domains. However, in the skills domain, the relations between all risk factors and recidivism were significantly stronger in adolescents without ID than in adolescents with ID. Although not or only borderline statistically significant, these risk factors were all negatively related to recidivism in adolescents with ID, whereas these risk factors were significantly and positively related to recidivism in adolescents without ID.

Conclusions: There are few differences between juvenile offenders with and without ID in the impact of risk factors for recidivism, suggesting that the same assessment methods can be used for juvenile offenders with and without ID. There were, however, differences between juvenile offenders with and without ID in the skills domain. What these differences mean for the treatment of juvenile offenders is yet to be determined. For now it is important to be aware of potential negative (side) effects on recidivism when skills training is offered to juvenile offenders with ID.