Methods: Data from a large longitudinal study of boys who were between kindergarten and age 13 years were used to (1) test whether Gray's and Cloninger's personality dimensions measured in kindergarten predicted the early onset of stable, highly delinquent behavior; (2) test whether 1, 2, or 3 dimensions were needed; and (3) test the predictive value of a categorical approach.
Results: The impulsivity dimension was the best predictor of the early onset of stable, highly delinquent behavior. Anxiety and reward dependence made significant but weaker contributions. The categorical approach corroborated Cloninger's suggestion that boys who are high in impulsivity, low in anxiety, and low in reward dependence would be more at risk for delinquent involvement. Boys who were high in impulsivity and low in anxiety but high in reward dependence were much less at risk for delinquency. Differences in antisocial behavior among extreme kindergarten personality groups were stable from ages 11 to 13 years.
Conclusions: The behavioral activating system appears to be the major dimension underlying the propensity toward early onset of antisocial behavior, but both the behavioral inhibition system and the need for social rewards play important roles. The behavioral style (personality) that results from the interplay of these systems is clearly in place by the kindergarten year. Preventive efforts should target preschool children with at-risk behavior profiles. However, longitudinal-experimental studies with at least yearly assessments between birth and school-entry age are needed to understand the extent to which the behavioral styles are antecedent to preschool disruptive behavior disorders.