Background: Some evidence suggests that prenatal exposure to maternal smoking contributes to the etiology of Attention-Deficit/Hyperactivity Disorder (ADHD). The present study tested an intervention targeting disruptive behavior to establish whether exposure to maternal smoking during pregnancy predicts intervention failure in elementary schoolchildren.
Methods: Five hundred and eight elementary schoolchildren were followed from ages 7 to 11. At ages 8 and 9, they were randomly assigned to a control condition, or to a two-year universal classroom-based intervention targeting disruptive behavior. Measures included maternal reports of smoking during pregnancy, teacher-rated symptoms of ADHD from ages 7 to 9 years, and children's self-report of experimentation with smoking at ages 10 and 11 years.
Results: At age 7, prenatally exposed children had higher ADHD symptom scores. The intervention did not affect the course of their ADHD symptoms and the probability of early-onset experimentation with smoking. Among non-exposed children, the intervention positively affected the course of ADHD symptoms, and reduced the probability of early-onset experimentation with smoking.
Conclusions: Prenatally exposed children are most prone to follow a path of high levels of ADHD symptoms and associated elevated risk for early-onset experimentation with smoking, which is unreceptive to a universal preventive intervention. In these children, the developmental course of ADHD symptoms seems to have been influenced by their prenatal exposure to maternal smoking. Future research should further explore whether prenatal smoking is a proxy measure that indexes another risk factor, or a causal factor for adverse developmental outcomes.