Post published on Bluesky on 27 Jul 2025 10:54

Abstract

While the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2) is considered a “reference standard” measure to observe symptoms of autism spectrum disorder (ASD), little is known about the utility of its Other Abnormal Behaviors or “E codes.” This study investigated the unique influence of each E code (overactivity, disruptive behavior, anxiety) on ADOS-2 scoring. Data from ADOS-2 administrations (Modules 1, 2, 3) were collected from 3364 children (mean age = 6.73 years) at an outpatient ASD clinic. For those with ASD, ADOS-2 Calibrated Severity Scores (CSS) were descriptively higher for those with overactivity and disruptive behavior, but lower for those with anxiety. For those without ASD, no patterns emerged when comparing means. After controlling for age, sex, and language level, multivariable linear models indicated the presence of overactivity was significantly associated with increased CSS for children with ASD compared to those without. No significant interaction was present for disruptive behavior. The presence of anxiety was significantly associated with increased Social Affect CSS only for those without ASD. All effect sizes were small. This is one of the first studies to evaluate the effect of each individual E code on ADOS-2 CSS. Unique differences emerged across diagnostic groups, suggesting implications for ADOS-2 interpretation. Lay Summary The Autism Diagnostic Observation Schedule, Second Edition (ADOS-2) is a common assessment tool used during an autism evaluation. As part of the ADOS-2, the examiner rates “E codes,” which are levels of hyperactivity, disruptive behavior, and anxiety during testing. These codes are not part of the final ADOS-2 score. While there is a lot of research on the ADOS-2, less is known about these E codes. This study looked at how the E codes might affect the final ADOS-2 scoring. Information came from 3364 in-person autism assessments (average age = 6.73 years) who were evaluated at an autism specialty clinic. For autistic children, ADOS-2 scores were higher (i.e. more autism-related behaviors) for those with overactivity and disruptive behavior, but lower for those with anxiety. For those without autism, there was no pattern. After accounting for the child’s age, sex, and language level, there were unique results for each E code, depending on whether the child received an autism diagnosis. This study is important as it is one of the first to evaluate the effects of each E code on ADOS-2 scores and could impact how scores are interpreted when considering an autism diagnosis.