Abstract: | The present longitudinal study examined resting heart rate and heart rate variability and reactivity to a stressful gambling task in adopted adolescents with aggressive, delinquent, or internalizing behavior problems and adopted adolescents without behavior problems (total N=151). Early‐onset delinquent adolescents showed heart rate hyporeactivity to the stress‐eliciting gambling task compared to late‐onset delinquent adolescents and adolescents without behavior problems. Heart rate, heart rate variability, and reactivity to stress were not related to environmental factors such as early‐childhood parental sensitivity, parental socioeconomic status, or adoptee's health status at arrival. We conclude that the distinction between delinquency and aggression and between childhood‐onset and adolescence‐onset delinquency is important for the study of stress reactivity in adolescents. |