ADHD Meds Do Not Lead to Future Drug Abuse

Sid Kirchheimer

January 06, 2003

Jan. 6, 2003 — Children who take medication to treat attention deficit hyperactivity disorder (ADHD) face no greater risk of future substance abuse, finds the latest study to test a theory that stimulants used to treat the disorder "sensitize" children to various types of drugs, paving the way for subsequent use.

Researchers say this study, published in the January issue of Pediatrics, is now the eleventh to find no evidence of the so-called "sensitization theory," suggesting that children treated with ADHD medications such as methylphenidate (Ritalin) , d-amphetamine (Adderall), and pemoline (Sylert) are more likely to smoke, drink, or take illicit drugs as teenagers or adults. Only one study documented an increased risk of later cocaine use among children who have been treated with these stimulants, which bring improvement in about 80% of children with ADHD.

"While stimulant medication is certainly not the only important intervention, it is the single most powerful intervention we have for treating ADHD," said study author and researcher Mariellen Fischer, PhD, of the Medical College of Wisconsin. "Putting a child on a stimulant medication is a very difficult decision for parents to make, even if children have substantial problems at home and at school, and one of the biggest worries that comes to mind is how will this impact their risk for later drug abuse."

That fear is largely due to earlier concerns, shared until recent years by the National Institute of Mental Health (NIMH), that long-term stimulant use in children might alter the way the brain reacts to those and other drugs, serving as a "gateway" for later tendency to abuse or addiction. These concerns stemmed largely from research in the early 1990s that measured brain activity in lab rats who were given stimulants — particularly dextroamphetamine, which is used to treat ADHD, but not as frequently as methylphenidate and other drugs.

"However, those researchers were administering doses that were far in excess to what would ever be used in humans," said Dr. Fischer. In her study, the researchers did not compare different types of stimulants used by their patients because the overwhelming majority were taking methylphenidate, which had not been implicated as much as dextroamphetamine in the animal studies.

Still, fears of the "sensitization theory" linger. As recently as last September, a congressional subcommittee met to discuss the issue, prompted by a campaign by the Citizens Commission on Human Rights, an affiliate of the Church of Scientology. In that meeting, an NIMH official stated that recent studies suggest that there is no evidence that ADHD medications increase risk of later drug abuse.

"There is an organized campaign to pass misinformation about the use of these stimulants," says E. Clarke Ross of Children and Adults with Attention Deficit Hyperactivity Disorder (CHADD), which serves as a clearinghouse for information about ADHD to patients and their families. "These findings are very important to families who want reassurance that ADHD treatment options are safe and effective — and particularly that stimulant medications are safe and effective."

Dr. Fischer's study tracked 147 clinic-referred hyperactive children for more than 13 years. They measured their tendency to use tobacco, alcohol, and drugs such as marijuana and cocaine in adolescence and early adulthood compared with another group not diagnosed with ADHD, along with how the ADHD patients took the treatment stimulants. All study participants were aged between 4 and 12 years when the study began.

"One might expect that the longer a child stayed on the medication, the greater their risk for sensitization, and later drug use," Dr. Fischer told Medscape. "But that didn't occur. There was no relationship at all."

Meanwhile, another report published in thesame issue of Pediatrics suggests that stimulant therapy in childhood may actually lead to a lower risk of later drug and alcohol use. In that article, another group of researchers examined six previous studies tracking nearly 1,000 patients into adolescence and adulthood, finding that those taking stimulants had a lower rate of later substance abuse compared with kids who were not treated with medication.

Pediatrics. 2003;111(1):97-109, 179-185

Reviewed by Gary D. Vogin, MD


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