We assessed anxiety consistent (i.e. “traditional”) and inconsistent (i.e. “atypical”) with diagnostic and statistical manual (DSM) definitions in autism spectrum disorder (ASD). Differential relationships between traditional anxiety, atypical anxiety, child characteristics, anxiety predictors and ASD-symptomology were explored. Fifty-nine participants (7–17 years, Mage=10.48 years; IQ>60) with ASD and parents completed semi-structured interviews, self- and parent-reports. Seventeen percent of youth presented with traditional anxiety, 15% with atypical anxiety, and 31% with both. Language ability, anxious cognitions and hypersensitivity predicted traditional anxiety, whereas traditional anxiety and ASD symptoms predicted atypical anxiety. Findings suggest youth with ASD express anxiety in ways similar and dissimilar to DSM definitions. Similarities support the presence of comorbid anxiety disorders in ASD. Whether dissimilarities are unique to ASD requires further examination.

Research on the expression and prevalence of co-occurring anxiety disorders and autism spectrum disorders (ASDs) has produced variable results, in part due to the diversity in sample ascertainment and composition, methodology, and the operationalization of anxiety across studies. The present review organizes these findings to consider whether anxiety symptoms reported in ASD are better categorized as (a) a part of ASD or (b) a comorbid disorder. Although there is some support for the presence of co-occurring, potentially comorbid anxiety disorders in ASD, a shift toward measurement validation and dimensional approaches in future research is needed to determine the role of anxiety in ASD, particularly regarding its "typical" and "atypical" presentation in this population.