Co-occurring Psychiatric Symptoms in Verbal, School-Aged Children With Autism Spectrum Disorder and at Least Average IQ

PURPOSE: Increased levels of co-occurring psychiatric symptoms are observed in children and adolescents with autism spectrum disorder (ASD). Former research often investigated heterogeneous samples of youth with ASD. However, concurrent symptom presentation appears to differ with individual characteristics such as intellectual abilities. METHOD: The present study investigated verbal, school-aged children and adolescents (n = 103) with ASD and at least average intellectual abilities (i.e., full-scale intelligence quotient, FSIQ). Co-occurring psychiatric symptomatology was assessed with the Child Behavior Checklist (CBCL). Path analyses were conducted to investigate whether autistic characteristics or intellectual abilities predicted co-occurring psychiatric symptoms. RESULTS: In the investigated youth with ASD the extent of co-existing symptoms was elevated in all CBCL syndrome domains. Few associations of Autism Diagnostic Observation Schedule (ADOS-2), Autism Diagnostic Interview (ADI-R), and FSIQ scores with concurrent psychiatric symptomatology were found, limited to small effect sizes. CONCLUSION: Within the investigated youth with ASD likelihood of experiencing elevated levels of co-occurring psychiatric symptomatology is increased. However, among individuals above the diagnostic threshold for ASD, variance in ASD symptoms may be of limited influence on concurrent symptom severity. Findings highlight the importance of diagnostics for co-occurring psychiatric symptoms in youth with ASD.