Adult ADHD and Substance Abuse

After a British tabloid photo of Michael Phelps apparently smoking marijuana at a college party surfaced early this month, the Olympic swimmer apologized to his fans and to the public, citing his youth, his “regrettable” behavior, and his “bad judgment.” What he didn't mention—and what may or may not have influenced his behavior—was attention deficit hyperactivity disorder (ADHD), a condition with which he was diagnosed at age 9.

About 60 percent of children with ADHD have symptoms that persist into adulthood. Phelps no longer takes medication for ADHD, and his mother has said he is now able to focus his attention using physical training (including swimming) and behavioral modification he learned as a child.

While the 14-time gold medalist is generally seen as an all-American role model, this most recent photo was not the first blemish on his record: In November 2004, Phelps—just 19 at the time—ran a stop sign and was arrested for driving under the influence.

In recent days, several blogs have raised Phelps’ ADHD in connection with the party photo, suggesting that he may have been “self-medicating”—that lots of people with ADHD smoke pot; or, at the very least, that they tend to act before thinking. Other commentators have suggested that Phelps is simply a normal 23-year-old cutting loose after years of rigorous training and self-discipline.

No one can say if ADHD played a role in Phelps’ behavior. However, the episode does serve as a reminder that there are unanswered questions about ADHD's impact on impulsive decision-making and substance use—and the importance of seeking diagnosis and treatment as soon as possible, before problems develop.

Research suggests that children with ADHD are more likely than their non-ADHD peers to drink alcohol and use drugs as teenagers. A 2003 study published in the Journal of Abnormal Psychology found that more than a third of the ADHD participants (out of 140 teenagers who had been diagnosed as children) reported smoking marijuana, compared to just over a quarter of the non-ADHD control group. Nearly twice as many in the ADHD group reported being drunk more than once in the previous six months.

For children whose ADHD continues into adulthood, the overall risk of developing a substance use disorder is as high as 50 percent, by some estimates. (Substance use disorders include a range of problematic drinking and drug-use patterns, not dependence or addiction alone.)

Inattention and impulsivity both play a role

Although the exact connection remains unknown, experts believe ADHD and substance use are linked by a complex blend of environmental and genetic factors.

"Some of the risk factors for ADHD are also risk factors for substance abuse," says Stephen Faraone, Ph.D., professor of psychiatry and behavioral sciences at SUNY Upstate Medical University. "The apparent genetic link between ADHD and substance abuse is pretty well validated by family studies and twin studies."

Several questions about the link between ADHD and substance use remain unanswered, however. It is unclear, for instance, whether the symptoms of ADHD—most notably impulsivity—lend themselves to substance use (and abuse), or whether negative effects of those symptoms (such as difficulty with school, work, or relationships) steer people toward drinking and drug use.