March 3, 2008 -- Children treated with stimulants for attention deficit hyperactivity disorder are no more likely to abuse drugs or alcohol during early adulthood than their untreated peers, new research shows.
More than 100 boys were followed for 10 years after they were diagnosed with ADHD, and those who took stimulants for the disorder were found to have no greater risk for later substance abuse than those who did not.
While some studies have linked the ADHD treatment to later substance abuse, others have not.
The new study is among the longest and most rigorously designed trials ever to address the issue, and the findings should reassure clinicians and parents weighing the risks and benefit of the treatment, says study co-author Michael C. Monuteaux, ScD, of Massachusetts General Hospital.
The National Institutes of Health (NIH)-funded study appears in the March issue of the American Journal of Psychiatry.
"This is strong evidence that treatment does not increase the risk for subsequent substance abuse," he tells WebMD.
ADHD, Stimulants, and Substance Abuse
The 112 study participants ranged in age from 16 to 27 at the end of the 10-year follow-up. Their average age was about 22.
Three out of four had been treated with stimulants for ADHD at some time during childhood; the rest had not.
The young men were asked about their use of alcohol, tobacco, and recreational drugs, and they were also assessed for the presence of psychiatric disorders associated with substance abuse using widely accepted testing methods.
Among the biggest shortcomings of earlier trials has been the failure to control for such disorders, Monuteaux says.
Stimulant use for the treatment of ADHD was found to have no impact on substance abuse later in life, he adds.
An earlier, four-year assessment of the same group of boys suggested that childhood use of stimulants for ADHD might help protect against later drug and alcohol abuse, but this was not the case in the 10-year follow-up.
This might mean that ADHD treatment has a role in delaying, but not preventing, substance abuse later in life, the researchers note.
The boys are being followed for an additional five years, during which time most will reach their mid-20s.
"That will give us a more definitive answer, since many of these boys have not reached the age where they are at the greatest risk for substance abuse," says Monuteaux, who is the assistant director of research for Massachusetts General Hospital's pediatric psychopharmacology program.
The Massachusetts General researchers are also following a group of girls with ADHD to determine if treatment affects their risk for abusing drugs or alcohol or tobacco later in life.
"We can't really say if these results can be extended to females," he says.
David Luckenbaugh, MA, of the National Institute of Mental Health (NIMH), agrees that the new study should reassure parents and clinicians.
Luckenbaugh and NIMH colleagues also found no link between stimulant use for ADHD and later substance abuse in an earlier, smaller study.
"This is good news," he tells WebMD. "Ten years is longer follow-up than we have seen, and the findings are pretty convincing."