Childhood Trajectories of Inattention, Hyperactivity and Oppositional Behaviors and Prediction of Substance Abuse/Dependence: A 15-Year Longitudinal Population-Based Study

Numerous prospective studies have shown that children diagnosed with ADHD are at higher risk of long-term substance abuse/dependence. However, there are two important limits to these studies: a) most did not differentiate the role of hyperactivity and inattention; b) most did not control for associated behavioral problems; c) most did not consider females. Our aim was to clarify the unique and interactive contributions of childhood inattention and hyperactivity symptoms to early adulthood substance abuse/dependence. Behavioral problems of 1804 participants (814 males) in a population-based longitudinal study were assessed yearly between 6 and 12 years by mothers and teachers. The prevalence of substance abuse/dependence at age 21 years was 30.7% for nicotine, 13.4% for alcohol, 9.1 % for cannabis and 2.0% for cocaine. The significant predictors of nicotine dependence were inattention (OR: 2.25; 95% CI: 1.63–3.11) and opposition (OR: 1.65; 95%: 1.20–2.28). Only opposition contributed to the prediction of cannabis dependence (OR: 2.33; 95% CI: 1.40–3.87) and cocaine dependence (OR: 2.97; 95% CI: 1.06–8.57). The best behavioral predictor of alcohol abuse/dependence (opposition) was only marginally significant (OR: 1.38; 95% CI: 0.98–1.95). Frequent oppositional behaviors during elementary school were clearly the most pervasive predictors of substance abuse/dependence in early adulthood. The association of childhood ADHD with substance abuse/dependence is largely attributable to its association with opposition problems during childhood. However, inattention remained a key predictor of nicotine dependence, in line with genetic and molecular commonalities between the two phenotypes suggested in the literature.