ADHD drugs seen as not linked to future drug abuse

WASHINGTON (Reuters) - Using stimulants like Ritalin to treat attention-deficit hyperactivity disorder in children, particularly younger ones, does not seem to boost the risk of later substance abuse, researchers said on Tuesday.

There has been a debate over whether such medications are the best way to treat ADHD, a condition marked by inattention, hyperactivity and impulsive behavior that appears more often in boys than girls. Some experts have worried these drugs could make children more prone to substance abuse later on.

Two teams of researchers who examined the issue in studies published in American Journal of Psychiatry said their findings should offer some reassurance about using these stimulants.

A team led by Salvatore Mannuzza of New York University followed for 17 years a group of 176 young men who had been prescribed Ritalin for ADHD as boys. Those who began taking Ritalin at ages 6 or 7 had essentially the same rate of drug abuse as young adults -- 27 percent -- as a group of young men who did not have ADHD and did not take Ritalin -- 29 percent.

Those with ADHD who started taking Ritalin at a slightly older age -- 8 through 12 -- did have a higher rate of future drug abuse -- 44 percent, the study found.

Mannuzza said it was premature to conclude it was the Ritalin, rather than the mere fact of having a condition like ADHD, that increased their likelihood of later drug abuse.

He said that question could be better answered by comparing children with ADHD treated with the medication starting at ages 8 to 12 with others with ADHD who were not treated with medication at all, to see if those groups had differing rates of drug abuse as adults.

"You can't conclude that late-treated cases will develop substance abuse even though that's what our findings seem to suggest," Mannuzza said.

Another team led by Dr. Joseph Biederman of Massachusetts General Hospital tracked for 10 years another group of boys with ADHD, some of whom were treated with stimulant medications and some not.

Those treated with medications had neither an increased nor decreased risk for subsequent drug or alcohol abuse compared to those not given drugs for their ADHD.

"Considering that ADHD affects 5 to 10 percent of children worldwide, and addictions are worldwide problems as well, I think the fact that these drugs do not have an adverse effect in increasing those risks is very important information for families and doctors taking care of children with ADHD," Biederman said in a telephone interview.

The U.S. National Institutes of Health, which helped fund the studies, estimates that between 3 and 5 percent of children have ADHD.

(Editing by Maggie Fox and Todd Eastham)