Stimulant treatment of children with ADHD reduces subsequent substance abuse

A study by researchers at Harvard University has provided more evidence that using stimulant medications such as methylphenidate to treat children with attention-deficit/hyperactivity disorder (ADHD) may reduce their risk of developing drug and alcohol use disorders later in life.

Dr. Timothy Wilens, lead investigator, and colleagues used a statistical method called meta-analysis (an examination of whether data compiled from multiple scientific studies provides evidence for statistical significance) to evaluate the relationship between stimulant therapy and subsequent substance use disorders (SUD) in youths with ADHD. After searching the literature for studies of children, adolescents, and adults with ADHD that had information on childhood exposure to stimulant therapy and later SUD outcomes, the researchers applied meta-analyses to six long-term studies. Two studies followed patients into adolescence and four followed patients into young adulthood. These studies comprised data from 674 youths receiving medication therapy for ADHD and 360 unmedicated youths with ADHD. Of those receiving medications, 97 percent were taking the stimulants methylphenidate or amphetamine.

From the compiled data, researchers found that youths with ADHD who were treated with stimulants had an almost two-fold reduction in the risk for developing SUD when compared with youths with ADHD who did not receive stimulants. Examination of each study individually suggested that stimulant medications might have a protective effect against the development of SUD.

Analysis of studies that reported follow-up into adolescence revealed that youths treated with stimulants were 5.8 times less likely to develop SUD than those not treated. However, analysis of studies that followed subjects into adulthood found that those treated with stimulants were about 1.5 times less likely to develop SUD. The researchers say that the less robust effect during adulthood may have occurred because the patients discontinued stimulant treatment when they reached a certain age or that parents may closely monitor the medications of youths with ADHD.

WHAT IT MEANS: Overall, treating ADHD pharmacologically appears to reduce the risk of substance abuse by half. Untreated, ADHD is associated with a two-fold increased risk for developing a substance abuse disorder. Hence, while not truly immunizing against substance abuse, treating ADHD pharmacologically reduces the risk for drug and alcohol abuse and addiction to the level of risk faced by the general population. The report¡¦s findings are among the most robust in child psychiatry demonstrating a protective effect of pharmacological treatment on reducing the risk for later substance abuse.

The study, funded by the National Institute on Drug Abuse (NIDA), is published in the January 6, 2002, issue of Pediatrics.

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