Boston Children's Hospital researchers found that a significant number of children diagnosed with autism as toddlers no longer meet the criteria for ASD when they reach school age.
When a parent receives the news that their son or daughter has autism spectrum disorder (ASD), they assume it will persist throughout the child's life. However, new research suggests this might not be the case with all children, especially those diagnosed with autism at a young age.
In the study, published on October 2 in JAMA Pediatrics, researchers at Boston Children's Hospital found that among toddlers diagnosed with ASD at 12 to 36 months, nearly 40% no longer met the diagnostic criteria of autism by age six.
These findings contradict previous research that showed autism persistence rates ranged from 68% to 100%.
To conduct the research, the investigators identified 213 children diagnosed with ASD at 12 to 36 months and followed them until they reached five to seven years of age. At the end of the follow-up, the researchers used criteria from the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) and other measures to determine whether the participants still met the diagnostic criteria for autism.
All participants received some type of intervention. However, 201 received autism-specific interventions such as applied behavioral analysis (ABA).
The research team found that at around six years of age, 37.1% of the participants did not meet diagnostic criteria for autism. In addition, females and participants with higher adaptive skills, including communication, decision-making, and self-care skills, were more likely to lose their autism diagnosis than males or children with a lower adaptive skill level.
Moreover, the researchers revealed that while most participants received intervention therapy, the intensity of these interventions did not play a significant role in whether a child had persistent or nonpersistent ASD.
Still, the study authors say that interventions do matter. However, their findings suggest the need for a more individualized approach when treating autistic children.
Are early autism diagnoses accurate?
Healthnews spoke with lead study author Elizabeth Harstad, M.D., M.P.H., an assistant professor of pediatrics at Harvard Medical School and attending physician in Developmental Medicine at Boston Children's Hospital, about whether inaccurate early autism diagnoses could play a role in the study's findings.
Harstad said, "These findings suggest that applying the current Diagnostic and Statistical Manual of Mental Disorders (DSM-5) behavioral criteria to young children may capture children with a range of developmental differences and that some children will continue to exhibit behavioral characteristics consistent with ASD, while others will not."
Although the study was not able to determine whether the children were initially misdiagnosed, Harstad says they identified participants with autism using the "gold standard" approach, which included a very rigorous clinical evaluation to determine if they met the diagnostic behavioral criteria for ASD.
For example, a team of providers, including a developmental-behavioral pediatrician and a psychologist, completed assessments of the participants' developmental skills and employed the Autism Diagnostic Observation Schedule (ADOS) — a behavioral observation test to assess ASD symptoms.
However, according to Harstad, some study participants who were initially diagnosed with ASD but did not meet autism diagnostic criteria later still displayed traits associated with the developmental disorder.
"We are currently analyzing the developmental profiles of the children who did not meet ASD criteria at the research assessment," Harstad explained. "It is possible that some children continued to have some traits associated with autism. For example, some of the children have reported communication difficulties."
Is it autism or something else?
Previous versions of the DSM-5 included Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS) as an autism diagnostic category. Before being removed from the DSM-5 in 2013, a child could be diagnosed with PDD-NOS instead of autism if they had some autistic traits but did not meet the full diagnostic criteria for ASD.
However, because the study found that nearly 40% of toddlers eventually lose their autism diagnosis by the time they reach school age, should clinicians consider PDD-NOS as a possible diagnosis for some children?
"Within the diagnosis of PDD-NOS, the diagnostic criteria could be applied fairly loosely, as there was not a minimum number of diagnostic criteria that had to be met for a child to receive the diagnosis of PDD-NOS," Harstad said.
Harstad doesn't believe the study's evidence suggests that clinicians should consider PDD-NOS for some children due to the lack of strict criteria associated with this diagnosis.
"Instead, perhaps an ASD diagnosis given at a young age (such as < 3 years old) should be thought of as an early 'ASD profile,'" Harstad explained. "A condition which requires support and interventions but should be assessed again in future years to determine if the symptoms persist or not."