Abstract
OBJECTIVE: Co-occurring anxiety affects 40-80% of autistic individuals; however, little is understood about how anxiety manifests in young autistic children, especially those with intellectual disability (ID), partly due to the paucity of measures designed to assess anxiety symptoms in this population. The present study examined the utility of the Modified Anxiety Dimensional Observation Scale (M-Anx-DOS), an observational measure of anxiety-related behaviors, in preschool-aged autistic children with and without ID. METHOD: This study included 48 autistic children (Mean age = 43.96 months; 81.3% with ID) and 30 non-autistic (NA) controls (Mean age = 43.66 months). Anxiety-related behaviors were measured during the M-Anx-DOS. Parent-reported anxiety symptoms were assessed via the Preschool Anxiety Scale-Revised (PAS-R). RESULTS: Groups exhibited comparable scores on both the M-Anx-DOS and PAS-R. Within the autism group, a subset of M-Anx-DOS scores were related to age, autistic features, or IQ. The M-Anx-DOS exhibited excellent inter-rater reliability and acceptable internal consistency. Convergent validity was promising, with specific M-Anx-DOS scores correlated with parent-reported social, separation, and overall anxiety symptoms. M-Anx-DOS scores were not correlated with parent-reported ADHD or externalizing symptoms, suggesting strong discriminant validity. CONCLUSIONS: This study provides preliminary evidence of the reliability and validity of the M-Anx-DOS. These findings are promising given the importance of observational measurement of anxiety and lack of existing measures for this critical developmental period. Given the sample size and the complexity of identifying prodromal signs of anxiety in young autistic preschoolers with ID, future longitudinal work is essential to replicate and extend this work.