Developmental Regression Followed by Epilepsy and Aggression: A New Syndrome in Autism Spectrum Disorder?

Autism spectrum disorder (ASD) with regression (ASD-R) involves the loss of previously attained developmental milestones, typically during the first or second year of life. As children age, it is not uncommon for them to develop comorbid conditions such as aggressive behaviors or epilepsy, which can inhibit habilitation in language and social function. In this paper, we hypothesize that aggressive behaviors and epilepsy more commonly develop in patients with ASD-R than in those without a history of regression (ASD-NR). We conducted a retrospective review of non-syndromic patients with ASD over 12 years of age and compared the rates of epilepsy and aggression between ASD-R and ASD-NR patients. Patients with ASD-R, as compared to ASD-NR patients, demonstrated non-significantly higher rates of epilepsy (51.8% vs. 38.1%, p = 0.1335) and aggressive behaviors (73.2% vs. 57.1%, p = 0.0673) when evaluated separately. The rates for combined epilepsy and aggression, however, were statistically significant when comparing ASD-R versus ASD patients (44.5% vs. 23.8%, p = 0.0163). These results suggest that epilepsy with aggression is more common in ASD-R as compared to ASD-NR patients. When considering the impact of epilepsy and aggression on quality of life, these co-morbidities effectively cause a second regression in patients who experienced an earlier regression as toddlers. A larger, prospective trial is recommended to confirm these associations and further define the timeline in which these characteristics develop from early childhood to adolescence.