A new study suggests that stimulants prescribed for ADHD may be responsible for a handful of unexplained deaths in children and adolescents. Researchers compared medical records and parent interviews of children and teens who died between 1985 and 1996, including 564 who died from unexplained heart-rate abnormality. When they excluded deaths that had other possible causes--such as asthma or congenital heart defects--researchers found that 1.8 percent of the group had been taking a stimulant...