Objective: Previous research on developmental regression in youth with autism spectrum disorders (ASD) has often been limited by the definition, assessment, and methodology used to evaluate and describe regression. This study sought to overcome these limitations by examining the prevalence, timing, and correlates of documented cases of developmental regression in a large, epidemiological sample of youth with ASD.
Method: Utilizing a population-based surveillance methodology, this study includes 862 youth with ASD identified through abstraction and clinician record review.
Results: Approximately 21% of the sample had developmental regression documented in their medical or educational records with the mean age of regression being 24.2 ± 14.3 months. Youth with ASD and a history of regression were more likely to have comorbid intellectual disability, a prior community diagnosis of ASD, and be eligible for educational services as a student with autism. Youth with a documented history of regression also had higher rates of restricted, repetitive behaviors, such as stereotyped speech, nonfunctional routines/rituals, and sensory interests.
Conclusion: Results suggest that youth with a history of regression are not only more likely to have comorbid intellectual disability but are also are more likely to have been previously diagnosed with ASD in the community, suggesting that development regression may play an important role in identifying children who are at the risk for ASD and need evaluation. Higher rates of restricted, repetitive behaviors in youth with a documented history of regression may also provide important insights into the relationship between ASD and developmental regression.