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The Relationship of Intellectual Disability to Traditional and Distinct Anxiety Presentations in Children with ASD
Research suggests that children with ASD present with “traditional,” anxiety disorders (e.g., specific phobia, generalized, separation, and social anxiety) as well as distinct forms of anxiety, such as fears of change and idiosyncratic phobias (e.g., fear of gloves). A prior study found that traditional and distinct anxieties can be reliably differentiated and that traditional, but not distinct, anxiety symptoms are positively associated with language ability in verbal children on the spectrum. Yet, rates of traditional and distinct symptoms have not been compared in children with ASD with and without intellectual disability (ID).
Objectives:
Research suggests that children with ASD present with “traditional,” anxiety (e.g., specific phobia, generalized, separation, and social anxiety) as well as distinct forms of anxiety, such as fears of change and idiosyncratic phobias (e.g., fear of gloves). A prior study found that traditional and distinct anxieties can be reliably differentiated, and that traditional, but not distinct, anxiety symptoms are positively associated with language ability in verbal children on the spectrum (Kerns et al., 2014). Yet, rates of traditional and distinct symptoms have not been compared in children with ASD with and without intellectual disability (ID).
Methods:
63 youth with ASD (ages 9–13 years: M=11.08, SD=1.82; 78% male; 44% with ID) were part of the middle childhood follow-up of a rigorous longitudinal study of biological and behavioral correlates of ASD known as the Autism Phenome Project (APP). Anxiety symptoms were assessed via the Anxiety Disorders Interview Schedule–Parent/Autism Spectrum Addendum (ADIS/ASA), a semi-structured interview validated to assess 10 types of traditional and distinct anxiety in ASD. The highest traditional and distinct clinical severity ratings (CSR; Range 0-8, 4 = cut-off for impairment) were used to categorize each child’s anxiety presentation and assess concordance with the report of anxiety symptoms exceeding clinical cut-offs on brief parent-report measures, including the CBCL, MASC, and SCARED.
Results: Per the ADIS/ASA, 68% of total children presented with impairing anxiety (CSR ≥ 4), including: 22% traditional anxiety only, 19% distinct anxiety only, and 27% with both. Rates of impairing distinct anxiety (ID 45% v. No ID 46%) and traditional anxiety (ID 39% v. No ID 60%) were not significantly different in children with, versus without, ID. Yet, though children without ID presented with varied traditional anxiety disorders (phobia 49%, generalized anxiety 26%, social anxiety 14%, separation anxiety 11%), those with ID had only phobia (36%) and OCD (4%). In contrast, both children with and without ID presented with distinct anxieties, including social confusion fears (10%, 9%), idiosyncratic phobia (14%, 14%), fears of change (14%, 23%), and worries about special interests (3%, 11%). Brief parent-report measures had limited sensitivity in the sample, particularly amongst those with ID (Table 1).
Conclusions: This study provides further evidence of both traditional and distinct presentations of impairing anxiety in youth with ASD and suggests that brief parent measures lack sensitivity. Anxiety may be missed in youth with ASD when the content of their worries/fears varies from traditional conceptualizations or when their cognitive and their language abilities are impaired.