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ASD symptom severity differences increased by age 6 years

Only a small portion of developmental trajectories in autism spectrum disorder severity and adaptive functioning occurs during the preschool years, suggesting that some children with more severe and stable symptoms show significant improvements.

“This finding highlights the importance of close surveillance of these two domains independently over time,” Peter Szatmari, MD, of the Centre for Addiction and Mental Health at The Hospital for Sick Children at the University of Toronto, and of the Pathways in ASD Study Team, and colleagues wrote.

Peter Szatmari

The research team collected prospective data of 421 newly diagnosed preschool children with autism spectrum disorder (ASD) aged 2 to 4 years at four points from diagnosis to age 6 years.

Data indicate that group 1 (11.4%) demonstrated less severe symptoms, with an improved trajectory (P<.05). However, group 2 (88.6%) presented more severe symptoms and a stable trajectory, researchers wrote.

Regarding adaptive functioning, group 1 (29.2%) displayed reduced functioning and a declining trajectory; group 2 (49.9%) appeared to have moderate functioning and a stable trajectory, and group 3 (20.9%) had higher functioning and improved trajectory (P<.05), based on study data.

Boys were more likely to be in the group with severe symptoms, but a more stable trajectory compared with girls in the study.

Conversely, earlier age of diagnosis was associated with being in a group with greater functioning and improvements, they wrote. Some of the differences increased by age 6 years, suggesting that improvements may be possible when diagnosis is determined earlier, they concluded.

Disclosure: The researchers report no relevant financial disclosures.