ANN ARBOR—Clinicians are apparently getting better at diagnosing autism in young children. More than 75 percent of children diagnosed with autism at age 2 appear to still have the condition at age 9, according to a report by a University of Michigan autism expert and colleagues from other universities.

Catherine Lord, director of the University of Michigan Autism and Communications Center, and colleagues studied 192 children who had been referred to autism clinics or centers in North Carolina and Chicago and 22 control children who were developmentally delayed but not referred for or diagnosed with autism. The report is in the June issue of Archives of General Psychiatry.

“Judgment of experienced clinicians, trained on standard instruments, consistently added to information available from parent interview and standardized observation,” the authors conclude.

Autism is a developmental condition characterized by difficulties with social interactions and communication and a tendency toward restricted and repetitive behaviors. Parents usually identify problems in their autistic children during the first year of life, but most diagnoses are not usually made until children are older.

The definition of autism has recently expanded to include milder conditions known as autism spectrum disorders, including Asperger’s syndrome and pervasive developmental disorder not otherwise specified (PDD-NOS).

In the study, the children were assessed at ages 2, 5 and 9 and diagnosed using three measures: a parent interview; an observational scale that clinicians used to rate the children’s social and communication behaviors; and the judgment of the clinicians who examined the children and made initial diagnoses.

Each child received a best-estimate diagnosis, made by two additional psychologists or psychiatrists who reviewed all three of these measures and discussed the diagnosis until they reached a consensus.

About 76 percent of those diagnosed with autism at age 2 received the same diagnosis at age 9, and 90 percent of those diagnosed with an autism spectrum disorder at age 2 received a diagnosis of autism or an autism spectrum disorder at age 9.

Parent interviews, observation scale scores and clinicians’ judgment at age 2 each independently predicted a diagnosis of autism at age 9, with clinical judgment most strongly linked.

For the diagnoses that did change between ages 2 and 9 years, 18 (8 percent) improved and 38 (18 percent) worsened. Only one in 84 children diagnosed with autism at age 2 was not diagnosed with autism or a spectrum disorder at age 9, while more than half of children diagnosed with PDD-NOS at age 2 received an autism diagnosis at age 9.

“There are real questions about the usefulness of PDD-NOS as a categorical diagnosis,” the authors write.” However, especially for very young children, having a way for experienced clinicians to acknowledge their uncertainly about some 2-year-olds was ultimately helpful as a means of flagging children who by age 9 years had a range of difficulties from autism to very mild social deficits.

“Because more than half of the children with PDD-NOS clinical diagnoses at age 2 years received best-estimate diagnoses of autism by age 9 years, health care professionals should be wary of telling parents that their young children do not have autism, only PDD-NOS.”

This work was supported by grants from the National Institute of Mental Health and the National Institute of Child Health and Human Development. Lord and Susan Risi, research coordinator at the U-M Autism and Communications Center, receive royalties from the publication of the Autism Diagnostic Interview-Revised and Pre-Linguistic Autism Diagnostic Observation Schedule, though at the time of this study the instruments were distributed free of charge.

article on children with PDD-NOSFor more on the U-M Autism and Communications Center and a video from recent news features on NBC’sFor more on Catherine Lord