Changes in the severity of autism symptom domains are related to mental health challenges during middle childhood

Many autistic children experience changes in core symptom severity across middle childhood, when co-occurring mental health conditions emerge. We evaluated this relationship in 75 autistic children from 6 to 11 years old. Autism symptom severity change was evaluated for total autism symptoms using the autism diagnostic observation schedule calibrated severity score, as well as social-communication symptoms calibrated severity score, and restricted/repetitive behaviors calibrated severity score. Children were grouped based on their symptom severity change patterns. Mental health symptoms (attention-deficit hyperactivity disorder, anxiety, disruptive behavior problems) were assessed via parental interview and questionnaire and compared across the groups. Co-occurring mental health symptoms were more strongly associated with change in social-communication symptom or restricted/repetitive behavior severity than with total autism symptom severity. Two relevant groups were identified. The social-communication symptom-increasing-severity-group (21.3%) had elevated and increasing levels of anxiety, attention-deficit hyperactivity disorder, and disruptive behavior problems compared with children with stable social-communication symptom severity. The restricted/repetitive behavior-decreasing-severity-group (22.7%) had elevated and increasing levels of anxiety; 94% of these children met criteria for an anxiety disorder. Autism symptom severity change during middle childhood is associated with co-occurring mental health symptoms. Children that increase in social-communication symptom severity are also likely to demonstrate greater psychopathology, while decreases in restricted/repetitive behavior severity are associated with higher levels of anxiety. Lay abstract: For many autistic children, the severity of their autism symptoms changes during middle childhood. We studied whether these changes are associated with the emergence of other mental health challenges such as anxiety and attention-deficit hyperactivity disorder. Children who had increased social-communication challenges had more anxiety and attention-deficit hyperactivity disorder symptoms and disruptive behavior problems than other children. Children who decreased their restricted and repetitive behaviors, on the contrary, had more anxiety. We discuss why these changes in autism symptoms may lead to increases in other mental health concerns.