New research bolsters evidence that stimulants like Ritalin used for attention deficit problems may stunt children's growth, but it does not address whether the effect is permanent.
Children who took stimulants during the two-year study grew more than half an inch less and gained more than eight pounds less than those who weren't medicated.
The study involved 540 youngsters with attention deficit hyperactivity disorder, who were aged 7 to 9 at the outset of the study and were randomly assigned to receive common treatments including medication, behavior management and a combination of the two.
Girls generally reach their final height around age 16 and boys around age 18, so it's too soon to tell if the growth delays continued or were permanent, the researchers said.
American Academy of Pediatrics' guidelines that recommend treating ADHD with stimulants and behavior therapy say evidence collected by following youngsters into adulthood indicates the drugs don't cause any significant height reduction.
Weight loss, however, is a known potential side effect from long-term stimulant use.
The study, led by University of California at Berkeley researcher Stephen Hinshaw, was funded by the National Institute of Mental Health and appears in the April issue of Pediatrics.
Initial results after 14 months of follow-up, published in 1999, showed that drugs alone or used with behavior therapy were the most effective treatment.
The 24-month follow-up found that drug treatment with or without behavior therapy remained superior, though the effect diminished somewhat over time. The researchers attributed this in part to patients stopping or starting medication.
ADHD, the most common neurobehavioral disorder in childhood, affects 4 percent to 12 percent of U.S. school-age children. Symptoms may include short attention span, impulsive behavior, and difficulty focusing and sitting still.