In a new study, researchers found that during early childhood, girls with autism tend to show greater reduction and less rise in their autism symptom severity than boys with autism.
The research was conducted by a team at the UC Davis MIND Institute.
Early childhood is a period of substantial brain growth with a critical ability for learning and development. It also is the typical time for an initial diagnosis of autism and the best time for early intervention.
In the U.S., about 1 in 54 children have been identified with autism spectrum disorder (ASD), with four times as many boys with ASD as girls.
Previous studies have shown inconsistent results in terms of changes in autism severity during childhood. The general sense was that the severity of autism at diagnosis would last a lifetime.
In the study, the team evaluated changes in symptom severity in early childhood and the potential factors associated with those changes.
It included 125 children (89 boys and 36 girls) with ASD from the Autism Phenome Project (APP), a longitudinal project in its 14th year at the MIND Institute.
The children received substantial community-based autism intervention throughout their childhood.
The researchers classified participants based on their severity change score into a Decreased Severity Group (28.8%), a Stable Severity Group (54.4%), and an Increased Severity Group (16.8%).
One key finding was that children’s symptom severity can change with age. In fact, children can improve and get better.
The team found that nearly 30% of young children have less severe autism symptoms at age 6 than they did at age 3. In some cases, children lost their autism diagnoses entirely.
It is also true that some children appear to get worse. Unfortunately, it is not currently possible to predict who will do well and who will develop more severe autism symptoms and need different interventions.
Optimal outcome is a standard achieved when someone previously diagnosed with ASD no longer meets autism diagnostic criteria due to loss of autism symptoms.
In this study, seven participants (four girls and three boys) had an ADOS CSS below the ASD cutoff at age 6, potentially indicating optimal outcome.
Children showing decreasing symptom severity had better adaptive skills in multiple domains compared to those in the stable or increased severity groups.
Girls and boys might be characterized by different manifestations of autism symptoms. Girls might show better developmental results than boys in cognition, sociability, and practical communication skills.
The team found that girls with autism decrease in severity more than boys and increase in severity less than boys during early childhood.
One possible explanation for this difference is the girls’ ability to camouflage or hide their symptoms. Camouflaging the characteristics of autism includes masking one’s symptoms in social situations.
This coping strategy is a social compensatory behavior more prevalent in females diagnosed with ASD compared to males with ASD across different age ranges, including adulthood.
The study also found that IQ had a significant relationship with change in symptom severity. Children with higher IQs were more likely to show a reduction in ASD symptoms.
The researchers could not identify a relationship between early severity levels and future symptom change.
Surprisingly, the group of children with increased symptom severity at age 6 showed significantly lower severity levels at age 3, and their severity scores were less variable than the other groups.
One author of the study is David Amaral, a distinguished professor of psychiatry and behavioral sciences, faculty member at the UC Davis MIND Institute.
The study is published in the Journal of Autism and Developmental Disorders.
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