The study was partially funded by the Food and Drug Administration, but agency experts say there may be problems with the methodology, causing errors in the results.
Drug companies maintain the use of stimulants "is" safe for most children. But a mother whose son was on ADD medication blames the drug for her child's sudden death.
"How do you explain a 14-year-old dying of a heart attack with no prior health problems. Her doctor says stimulant drugs can cause sudden death as a result of cardiac arrest," said the victim's mother Ann Hohmann.
The study is published in today's issue of the "American Journal of Psychiatry." The FDA says it is collecting data for a larger, more in-depth study of the drugs' risks.