Researchers further say these stimulants, such as Ritalin, may actually have a protective effect when it comes to substance addiction.
The researchers "found absolutely no evidence" for later substance abuse, says Mariellen Fischer, a professor of neurology at the Medical College of Wisconsin in Milwaukee and second author of a 13-year prospective study that appears in the January issue of Pediatrics. "Stimulants are the first-line medications. They work the best and we know the most about them and they're the safest. I think we'll feel more comfortable using them now."
"We asked, 'Does treating younger children predispose them to becoming substance abusers?' The very straightforward answer to that is 'no,'" adds Dr. Timothy Wilens, a child psychiatrist at Massachusetts General Hospital in Boston and lead author of a second study, also appearing in Pediatrics. "As for the second question -- 'Does it help?' -- we think that the answer to that is, 'Yes, it does help.'"
ADHD is on the rise among American schoolchildren, with some 4 percent to 9 percent of youths affected, according to information in the Wilens study. The preferred treatment for the disorder, which usually manifests with restlessness, lack of focus and impulsivity, is stimulants such as Ritalin.
These medications have had great success with ADHD, with some 74 percent to 97 percent of children responding positively. Although 10 previous studies failed to find evidence that the stimulants made children more prone to drug abuse, parents remain wary.
"A lot of our parents are very concerned about the use of stimulant medication leading to substance abuse, and that's a complex concern," says Patricia Saunders, a clinical psychologist and director of Graham Windham's Manhattan Mental Health Center in New York City, the oldest child welfare agency in the country. "I doubt that any psychiatrist prescribing medication or psychologist or clinical social worker working with children shares the concern to that degree."
Addiction, Saunders says, involves many complex factors. In addition to a biological component, there are also socioeconomic and cultural vectors. It was a biological factor that raised a red flag regarding future addictive behavior. The stimulants used to treat ADHD affect the same neurotransmitters as some drugs of abuse.
The 13-year prospective study followed 147 hyperactive children, 98 of whom received stimulant medication. The children were aged four to 12 at the beginning of the study and were checked again at adolescence (mean age 15) and in early adulthood (mean age 21).
"Thirteen years is enough time," Fischer says. "We're talking about a period of time that's the highest risk of substance abuse, too."
With one small exception, the researchers found that children diagnosed with ADHD and taking stimulants had no greater risk than those not taking stimulants for turning towards illegal drugs when they were older. As for the exception (a small increased risk for trying cocaine one time in high school), "we really think that had to do more with the individuals the children were associating with," Fischer says.
The second study was a meta-analysis that assessed six existing studies, and it concluded that stimulant therapy in childhood actually resulted in a 1.9-fold reduction in the risk for substance abuse later on.
No one is sure why stimulants have these effects, but experts have an idea as to why it might be so.
"My gut feeling from a research standpoint and clinical standpoint is that when you reduce the demoralization, when you improve self-esteem and academic performance, these are three very bad risks for substance abuse," Wilens says. Successfully treating ADHD also reduces a child's social isolation and lessens the likelihood that they'll end up in the wrong crowd.
"What we know from ADHD kids is that they will aggregate to other kids eventually but a tougher peer group," he says.
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