Young children who are prescribed stimulants to treat attention-deficit hyperactivity disorder (ADHD) are no more likely to have alcohol or other drug addiction problems later in life than other young people, according to researchers.

However, older kids given Ritalin did have higher rates of drug problems as adults, one study found.

Reuters reported April 1 that researcher Salvatore Mannuzza of New York University and colleagues tracked 176 young men prescribed Ritalin as 6- and 7-year-olds and found that they had about the same rate of addiction problems (27 percent) as adults as a control group that had not received Ritalin (29 percent). However, kids prescribed Ritalin between the ages of 8 and 12 did have higher rates of drug problems as adults (44 percent).

Mannuzza said that researchers could not establish a cause-and-effect relationship among the older group until the older cadre of Ritalin users is compared to other kids of the same age who had ADHD but were not treated with stimulants. "You can't conclude that late-treated cases will develop substance abuse even though that's what our findings seem to suggest," Mannuzza said.

In a separate long-term study, however, researcher Joseph Biederman of Massachusetts General Hospital and colleagues found that boys treated with ADHD drugs had no greater risk of addiction a decade later than those with ADHD who did not receive stimulants like Ritalin.

The research was published in the American Journal of Psychiatry.