Connection between Childhood ADHD and Risk of Substance Abuse

Data collected from two long-term studies verifies previous claims that ADHD alone drastically increases the risk of cigarette smoking and substance abuse.

It has been reported that data collected from two separate long-term studies verifies previous claims that Attention-Deficit Hyperactivity Disorder (ADHD) alone drastically increases the risk of cigarette smoking and substance abuse in both boys and girls.

The studies were both centered around the influence of ADHD on the development of psychiatric disorders in young adults.

"Our study, which is one of the largest set of longitudinal studies of this issue to date, supports the association between ADHD and substance abuse found in several earlier studies and shows that the increased risk cannot be accounted for by co-existing factors such as other psychiatric disorders or family history of substance abuse," said Timothy Wilens, MD, leader of the study performed by researchers at Massachusetts General Hospital (MGH).

"Overall, study participants diagnosed with ADHD had a one and a half times greater risk of developing substance abuse than did control participants," said Wilens.

Previous data from studies performed by investigators at MGH and other institutions have discovered an increased risk of substance abuse in adolescents and young adults with ADHD.

But speculations have been raised concerning whether particular aspects of ADHD—such as impulsive behavior, cognitive problems, educational roadblocks, associated conditions such as bipolar disorder or conduct disorder, or family factors—could actually be factors responsible for the increase in risk.

To examine these potential factors, the researchers analyzed data from two previous studies—one of boys, one of girls–which assessed the pervasiveness of numerous psychiatric and behavioral disorders in participants diagnosed with ADHD as children.

From those two combined studies, more than a decade of follow-up information was available for the 268 participants with ADHD and 220 control participants; both groups were divided equally by gender.

32% of the 268 ADHD participants developed a form of substance abuse (cigarette smoking included) during the follow-up period, while only 25% of the 220 control participants had substance abuse issues.

Exterior factors such as gender, cognitive difficulties, mood disorders, educational roadblocks, or family history of substance abuse were found to have no impact on the risk of developing substance abuse problems.

The only factor that had an effect was the diagnosis of conduct disorder, which tripled the risk in combination with ADHD.

"Anyone with ADHD needs to be counseled about the risk for substance abuse, particularly if they have any delinquency," explained Wilens. "We still need to understand why some kids with ADHD develop substance abuse and others don't, whether particular treatment approaches can prevent substance problems and how best to treat young adults that have both ADHD and substance abuse."

The report from MGH investigators will appear in the Journal of the American Academy of Child & Adolescent Psychiatry.