This study is the first to examine teenage substance abuse and treatment for ADHD in a large multi-site sample. It also is the first to recognize that increased use of cigarettes in teenagers with ADHD histories commonly occurs with use of other substances such as alcohol and marijuana.
"This study underscores the significance of the substance abuse risk for both boys and girls with childhood ADHD," said Brooke Molina, Ph.D., professor of psychiatry and psychology at the University of Pittsburgh School of Medicine and lead author of the report. "These findings also are the strongest test to date of the association between medication for ADHD and teenage substance abuse."
Researchers studied nearly 600 children over an eight-year period from childhood through adolescence to test the hypothesis that children with ADHD have increased risk of substance use and abuse or dependence in adolescence. Molina and colleagues also examined substance abuse patterns, the effects of ADHD medications over time, and the relationship between medication and substance use.
The findings showed:
- When the adolescents were an average of 15 years old, 35 percent of those with ADHD histories reported using one or more substances, as compared to only 20 percent of teens without ADHD histories.
- Ten percent of the ADHD group met criteria for a substance abuse or dependence disorder, which means they experienced significant problems from their substance use, as compared to only 3 percent of the non-ADHD group.
- When the adolescents were an average of 17 years old, marijuana was particularly problematic with 13 percent versus 7 percent of the ADHD and non-ADHD groups, respectively, having marijuana abuse or dependence.
- Daily cigarette smoking was very high at 17 percent of the ADHD group, a significantly higher rate than national estimates for this age. The smoking rate of non-ADHD teens was only 8 percent.
- Alcohol use was high in both groups, highlighting its common occurrence for teenagers in general.
- Substance abuse rates were not different for children who were still being treated with ADHD medication compared to children who were not.
"We are working hard to understand the reasons why children with ADHD have increased risk of drug abuse. Our hypotheses, partly supported by our research and that of others, is that impulsive decision making, poor school performance, and difficulty making healthy friendships all contribute," added Molina.
"Some of this is biologically driven because we know that ADHD runs in families. However, similar to managing high blood pressure or obesity, there are non-medical things we can do to decrease the risk of a bad outcome. As researchers and practitioners, we need to do a better job of helping parents and schools address these risk factors that are so common for children with ADHD."