A University of Florida study is among the first to evaluate whether a child’s age at the time of an attention deficit hyperactivity disorder diagnosis influences treatment and raises numerous questions about why young children with ADHD are being heavily medicated.

Researchers in the UF College of Pharmacy determined that a child’s age when diagnosed with ADHD may be a strong predictor of the types and number of medications that are later prescribed to treat psychiatric conditions.

“There is a significant amount of ADHD drug treatment happening at a young age that is not supported by evidence,” said Almut Winterstein, PhD, a professor and the Dr. Robert and Barbara Crisafi Chair in Pharmaceutical Outcomes and Policy at the college, part of UF Health, the university’s academic health center. “In many instances, we do not know the impact these drugs have on the developing brain and whether any physical side effects may happen.”

Published in the Journal of Clinical Psychiatry, the study found that preschoolers with ADHD were more likely to receive antipsychotics, anticonvulsants and multiple mental health drugs during a five–year follow–up period compared with children with later–onset ADHD. The probability of a 3–year–old diagnosed with ADHD ending up on three mental health drug classes at the age of 8 was about 40 percent. In contrast, an 8–year–old’s probability of being on three drug classes when diagnosed with ADHD at age 8 was less than 10 percent and only increased about 13 percent by age 13.

For children diagnosed with ADHD between ages 3 and 9, each year of follow–up increased the probability of taking multiple mental health drugs and antipsychotic and anticonvulsant use, with the most profound effect in children diagnosed at age 3. In contrast, children diagnosed after age 9 showed no significant growth in any of the three outcomes over time.

American Academy of Pediatrics guidelines state that behavioral therapy is the recommended first–line treatment for ADHD in young children and should be tried before medication is prescribed.

The role of behavioral therapy in a treatment plan is one of a host of questions raised by the findings. UF researchers point out the treatment regimens, and the rationale for such clinical decisions, do not make a lot of sense. For instance, why did 40 percent of patients in the study diagnosed with only ADHD receive a triple combination of drugs, when two of the drug classes have no evidence of effectively treating ADHD?

“This study raises a lot of questions,” Winterstein said. “What is driving the treatment of young children, who seem to only have ADHD, with so many mental health drugs is a very important clinical research question that needs to be understood.”

To execute the study, Medicaid billing records from more than 16,500 children and adolescents in 28 states were analyzed between 1999 and 2006. A patient’s medications were evaluated in one–year intervals following the first observed diagnosis of ADHD. Children were followed for five years to assess the use antipsychotic, anticonvulsants and multiple mental health medications.

Rene Soria–Saucedo, PhD, an assistant professor of pharmaceutical outcomes and policy in the UF College of Pharmacy, was as a co–author of the study.