Jacolien H. van der Maas; The Influence of IQ on the Relationship between Stressful Life. Events and Severity of Delinquency among Dutch Incarcerated Male Adolescents

Research has consistently shown that juvenile delinquent behavior is related to risk factors such as a lower IQ and the experience of stressful life events. The aim of this study was to investigate the role IQ plays in the relationship between stressful life events and the severity of delinquency among Dutch incarcerated male adolescents.

In this study, 163 incarcerated male adolescents, aged 12-18 years old, were screened for stressful life events using JTV (Childhood Trauma Questionnaire) and were tested with the Wechsler Intelligence Test (WISC-III or WAIS-III). Criminal offences of these juvenile were categorised into twelve categories from least to most severe offences (Brand et al., 2005).

Our main findings were significant relationships between Verbal IQ (VIQ) and severity of delinquency, as well as Performance IQ (PIQ) and severity of delinquency. Another interesting finding was the prevalence of almost equal groups of disharmonic profiles of VIQ < PIQ and VIQ > PIQ. These results are noteworthy, because a number of previous studies have found a regular pattern of a higher prevalence of VIQ < PIQ profiles and a smaller number of VIQ > PIQ profiles. Unexpectedly, no moderation effect of Verbal IQ on the relationship between stressful life events and severity of delinquency was found. These results nevertheless suggest that it is important to stimulate the cognitive development of at risk juveniles, in order to reduce the likelihood of delinquency and recidivism.