Affective Internalizing Problems Related to Age in Children and Adolescents with High Functioning Autism

Background: Clinical reports have suggested increased rates of affective internalizing symptoms among adolescents with autism spectrum disorders (ASDs). A recent study of children with ASDs and a broad range of intellectual functioning reported that age was positively related to anxiety symptoms. Another study documented a relationship between depression and intellectual and social functioning in a sample of high functioning adults with ASDs; depressed individuals had significantly higher IQ and significantly lower autism symptoms than non-depressed individuals. To the authors' knowledge, the current study is the first to examine the relationship between affective internalizing problems and age, IQ, and autism symptoms in a large sample of high functioning children and adolescents with ASDs. Objectives: Examine the relationship between parent reported affective internalizing symptoms (anxiety, depression, and withdrawal) and age, IQ, and autism symptoms in a high functioning cohort of children and adolescents with ASDs. Methods: Subjects were a clinically referred sample of 157 high functioning children/adolescents (mean age=8.5+3.2 years; verbal or nonverbal IQ > 75) diagnosed with an ASD based on the Autism Diagnostic Interview, Autism Diagnostic Observation Schedule (ADOS), and clinical impression. Subjects also received a comprehensive neuropsychological battery which included the parent report versions of the Behavioral Assessment System for Children (BASC) or the Child Behavior Checklist (CBCL) and an IQ measure. Based on recommendations from the authors of the BASC, we computed an Affective Internalizing Problems (AIPs) composite (Anxiety, Depression, and Withdrawal) so as to include both BASC and CBCL data. Results were analyzed using correlations between BASC or CBCL AIPs and age, IQ, and ADOS symptoms (Communication and Social Domains). Additionally, overall AIPs for children (age 2-11) and adolescents (age 12-17) were compared. Results: Age was significantly correlated with AIPs, r(155) = .35, p<.01, so that older age was associated with greater AIPs. There was also a significant age group difference, t(155) = 3.2, p<.01, with adolescents experiencing higher mean AIPs than children. Mean adolescent AIP T-scores fell within the borderline clinical cutoff (mean AIP T-score=66+9.1, borderline clinical cutoff ≥ 65). IQ, Communication Domain symptoms, and Social Domain symptoms were not related to AIPs. Conclusions: In this large group of high functioning children and adolescents with ASDs, increased age is related to higher levels of AIPs. The adolescents fell on average in the borderline clinical range for AIPs, significantly above their younger counterparts. This finding may be significant clinically, as it supports accounts of increased risk for AIPs during adolescence. Unlike recent findings in a high functioning sample of adults with ASDs, IQ and autism symptoms were not related to internalizing problems among our high functioning children and adolescents.