CHICAGO — Psychostimulants are commonly prescribed for children with autism, and that treatment is often continued for several years, according to results of a large new study, Katherine Nickels, M.D., reported at the annual meeting of the Society for Developmental and Behavioral Pediatrics.
Nearly two-thirds of children with autism in a population-based cohort received psychopharmacologic treatment, with more than half having been treated with psychostimulants.
Previous studies have shown that 6.7%–20% of children with autism are treated with psychostimulants. But these studies were small or had biased subject populations, said Dr. Nickels, a pediatric resident at the Mayo Clinic, Rochester, Minn.
“What makes our research unique is that it is a large, population-based cohort of research-identified autism spectrum disorders,” Dr. Nickels said.
“The patients were nonreferred and represent every case of autism spectrum disorders in a population at risk,” she said.
Using data from the Rochester Epidemiology Project, Dr. Nickels and colleagues identified 124 patients that fulfilled the DSM-IV research criteria for autism. Ninety-five were male and 29 female, and the majority were cognitively impaired, as defined by an IQ of 70 or less.
The children were drawn from all 0- to 21-year-old residents of Olmsted County, Minn., who received either inpatient or outpatient care at all sites providing medical care from 1976 to 1997.
Information on all psychopharmacologic medications ever used was abstracted, including name, dose, and dates at which treatment was started and stopped. Duration of follow-up was defined as the time between the first and last documented medical visits. Treatment outcomes were not assessed.
Psychopharmacologic treatment of any kind was used for 82 cases (66%). Among these, 65 patients (79%) were treated with psychostimulants. Overall, 53% of the 124 patients with research-identified autism were treated with stimulants.
There was no difference in stimulant use by gender (53% male vs. 52% female). The median age at which treatment began was 8 years.
The most commonly prescribed stimulant was methylphenidate (80%), followed by dextroamphetamine (54%), and mixed amphetamine salts (20%).
The median time between the first and last documented psychostimulant treatment was 4.3 years. Median duration of follow-up was 12.5 years overall for autism cases and 13.9 years for cases treated with stimulants.
The study did not look at the difference in treatment preference by decade. But, some children were diagnosed after treatment began.
“Some of these children were treated at a time when autism and autism spectrum disorders were not a very popular diagnosis,” Dr. Nickels said. “I remember reading through charts of children, who very obviously fit all DSM-IV criteria, and yet their symptoms were still blamed on their mothers.”
The study was limited in that it was retrospective, although the investigators were able to apply the DSM-IV criteria to all patients given the detailed records available on this medically well-served population.
Additionally, the racial demographics of the study (96% white) suggest caution in generalizing the findings to the U.S. population, Dr. Nickels said. However, a recent population-based study demonstrated that the rate of autism spectrum disorders is comparable between African American and white children.