Shankar Vedantam:

Children taking stimulant drugs such as Ritalin to treat attention-deficit hyperactivity disorder are several times as likely to suffer sudden, unexplained death as children who are not taking such drugs, according to a study published yesterday that was funded by the Food and Drug Administration and the National Institute of Mental Health.
While the numbers involved in the study were very small and researchers stopped short of suggesting a cause and effect, the study is the first to rigorously demonstrate a rare but worrisome connection between ADHD drugs and sudden death among children. In doing so, the research adds to the evolving puzzle parents and doctors face in deciding whether to treat children with medication.
Doctors have speculated about such a connection in the past because stimulants increase heart rate and have other cardiovascular effects. Physicians are currently advised to evaluate patients for cardiac risks before prescribing the drugs, and FDA officials said yesterday that those guidelines do not need strengthening in light of the new study. About 2.5 million children in the United States take ADHD medications such as Ritalin and Adderall.