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Traditional and Distinct Symptoms of Anxiety in Youth with ASD and a Broad Range of Intellectual Functioning
Research suggests that youth with ASD present with both DSM-defined –hereon called “traditional”– anxiety disorders (e.g. specific phobia, generalized, separation, and social anxiety) and also more idiosyncratic –hereon called “distinct”– manifestations of anxiety, such as fears of change, anxiety around social rules/unpredictability and unusual phobias (e.g. fears of men with beards, toilets, sounds). Distinct symptoms share many qualities with traditionally-defined anxiety disorders (e.g. anticipatory worry, avoidance, physiological arousal), but do not fit DSM-defined anxiety categories and have historically been viewed as associated symptoms of ASD. The lack of clarity about where autism stops and anxiety begins contributes to variability in measurement and impedes progress in research. Furthermore, distinct anxiety may be particularly prone to being overshadowed by ASD, potentially reducing access to appropriate behavioral and cognitive-behavioral treatments.
Objectives:
The present study aimed to examine the rate and quality of traditional and distinct anxiety in a cohort of children with ASD and highly varied IQ. We also explored concordance between brief questionnaires and a gold-standard clinical interview for traditional and distinct anxiety.
Methods:
A preliminary sample of 24 youth (N=35 anticipated by 05/2017) with ASD (ages 9–15 years: M=11.96,SD=1.12; 70% male; 33% with IQ<70 (range: 31 - 170) were recruited as part of a longitudinal study of biological and behavioral correlates of ASD. Participants were enrolled at age 2-3.5 with follow-up assessment at 9-13 years (ongoing). Anxiety symptoms were assessed at follow-up via the Anxiety Disorders Interview Schedule–Parent/Autism Spectrum Addendum (ADIS/ASA), a gold standard clinical interview validated to assess traditional and distinct anxiety in ASD, the Child Behavior Checklist (CBCL), the Manifest Anxiety Scale for Children (MASC), and the Screen for Anxiety and Related Disorders (SCARED). ADIS/ASA Clinician Severity Ratings (CSRs; Range 0-8; CSR≥ 4 clinical cut-off for diagnosis/significant impairment) reflect anxiety-related impairment for traditional and distinct anxiety. The highest traditional and distinct CSRs were used to categorize each child’s anxiety presentation and assess concordance with brief measures.
Results:
Per the ADIS/ASA, 71% of children presented with clinical anxiety (CSR ≥ 4), including: 21% traditional anxiety, 21% distinct anxiety, 29% both. Clinical anxiety was as common in youth with and without ID, but there was a trend for youth with ID to have less traditional anxiety (X2 = 3.00, p=.08). Whereas the highest traditional anxiety CSR was correlated with SCARED (r=.57, p=.01), MASC (r=.67, p<.01), and CBCL Anxious/Depressed totals (r=.57, p=.01), distinct CSRs were not (r=-.14, .04 and .02 respectively). Exploratory analyses revealed that brief measures appeared more sensitive to DSM-anxiety in youth, but did flag anxiety in some youth with only distinct presentations (Table 1).
Conclusions:
This study illustrates the presentation of traditional and distinct anxiety in youth with ASD and a broad range of intellectual functioning. It suggests that brief measures detect traditional anxiety better than distinct symptoms and may fall particularly short for youth with ID. Anxiety may be particularly likely to be missed in youth with ASD when the content of their worries/fears varies from traditional conceptualizations or when their cognitive abilities are impaired.