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ADHD, which is characterized by difficulties in paying attention, in keeping still, and in suppressing impulsive behaviors, is usually treated with stimulants, such as methylphenidate (Ritalin) or dextroamphetamine (Dexedrine, Adderall) because these drugs reduce the behavioral and attentional problems connected to their ADHD. As a result, children with ADHD perform better in school and on the job and relate better to family and friends. Research indicates that between three and five percent of all school-age children have
ADHD, and that the disorder is about four times more prevalent among boys than girls.
"While some clinicians have expressed concern about giving stimulants to children with ADHD because they fear it might increase the risk that these children will abuse stimulants and other drugs when they get older, this study shows exactly the opposite," says NIDA Director Alan I. Leshner. "Treating the underlying disorder, even if with stimulants, significantly reduces the probability they will use drugs later on."
In the study, researchers at Massachusetts General Hospital, Harvard School of Public Health, and Harvard Medical School compared the incidence of substance use disorders in 56 boys with ADHD who had been treated with stimulants for an average of about 4 years, in 19 boys with ADHD who had not been treated with stimulants, and in 137 boys without ADHD. All boys were at least 15 years old when they were evaluated for substance use disorders involving alcohol, marijuana, hallucinogens, stimulants, or cocaine. In a substance use disorder, a person continues to use a mood- or behavior-altering substance despite the fact that this substance causes significant problems in the person's life.
Results of the study showed that 75 percent of the nonmedicated ADHD boys had at least one substance use disorder, compared to 25 percent of the medicated ADHD boys and 18 percent of the boys without ADHD. The researchers -- Dr. Joseph Biederman, Dr. Timothy Wilens, Eric Mick, Dr. Thomas Spencer, and Dr. Stephen Faraone -- calculated that treating ADHD with medication (stimulants were used in over 90% of cases) was associated with an 84 percent reduction in risk of developing a substance use disorder. These researchers will continue to study this entire group of boys in a followup study funded by NIDA.
In previous studies, these same researchers had found that nearly twice as many adults with ADHD also had developed at least one substance use disorder at some point in their lives, compared to adults without ADHD. The adults with ADHD had developed the disorder in childhood and, in most cases, the disorder was neither diagnosed nor treated until much later.
NIDA supports more than 85 percent of the world's research on the health aspects of drug abuse and addiction. The Institute also carries out a large variety of programs to ensure the rapid dissemination of research information and its implementation in policy and practice. Fact sheets on health effects of drugs of abuse and other topics can be ordered free of charge in English and Spanish, by calling NIDA Infofax at 1-888-NIH-NIDA (-644-6432) or 1-888-TYY-NIDA (-889-6432) for the deaf.
These fact sheets and further information on NIDA research and other activities can be found on the NIDA home page at http://www.nida.nih.gov.