DSM-5 Levels of Support and Autism Severity Ratings

Background: Given the variability in symptom severity within individuals with Autism Spectrum Disorder (ASD) and the need for quantifying the severity of symptoms for determining service provision needs, the authors of the DSM-5 ASD criterion included severity ratings in the areas of Social Communication(SC) and Restricted and Repetitive Behaviors (RRB). This severity marker is based on “Levels of Support” and classified in terms of Level 1 (“Requiring support), Level 2 (“Requiring substantial support”) and Level 3 (“Requiring very substantial support”). The inclusion of these ratings were not based on any empirical data and to date, few studies in which the relationship between the severity ratings of established measures of autism symptoms and severity such as the Autism Diagnostic Observation Schedule-Second Edition (ADOS-2), the Childhood Autism Rating Scale-Second Edition (CARS2) and the Social Responsiveness Scale-Second Edition (SRS-2) have been published (Reszka, et al, 2014; Weitlauf, et al, 2014). Further, the studies published thus far were conducted prior to the publication of the finalized DSM-5 ASD criterion. Thus, there is a need to examine the relationship between existing measures of autism symptoms, cognitive ability and adaptive skills to better understand how these variables may influence the assignment of DSM-5 severity ratings at the time of diagnosis.

Objectives: The goal of the current study is to investigate the relationship between autism symptoms, associated features of autism (cognitive ability, adaptive skills and language level) and the assignment of DSM-5 levels of support.

Methods: The data included within this study was obtained through a secondary data set pulled from the University of North Carolina TEACCH Autism Program Research Registry. The database contains records of 11, 358 individuals, 754 of whom, were evaluated for autism at one of the 7 outpatient community-based centers of the UNC TEACCH Autism Program in North Carolina, by a local school, or other agency that provided evaluation for autism and a diagnostic report from which the data was pulled and added to the database. DSM-5 Severity ratings of SC as well as RRB were available for all 754 individuals included within the dataset of the present study. The dataset included scores from measures of cognitive development, adaptive skills, and severity of autism (as measured by the ADOS2, CARS2, and/or SRS-2 when available). The TEACCH Centers conduct diagnostic evaluations on all ages from toddlers through adults. Thus, the age range of participants with DSM-5 Severity Ratings was 1 through 68 years.

Results: Preliminary analyses indicate that clinical impression of autism severity (.000), as measured by clinician ratings of severity of autism on the CARS2, scores of adaptive skills (.000), and severity of symptoms as measured by the ADOS (.022) were positively correlated with DSM-5 SC level of severity rating. Clinical impression as rated on the CARS2 (.000), and adaptive scores (.005) were positively correlated with DSM-5 RRB severity rating.

Conclusions: In a community based sample, clinician impressions and direct assessment of autism symptom severity were associated with DSM-5 Level of severity assignment. Implications for clinical diagnosis will be discussed.