Factors associated with DSM-5 severity level ratings for autism spectrum disorder.
DSM-5 autism severity ratings drift toward IQ; guard your ratings so they track core autism traits, not intelligence.
01Research in Context
What this study did
Mazurek et al. (2019) asked how clinicians set DSM-5 autism severity levels. They looked at 4,000 kids in the SPARK registry. Each child had an ADOS, an IQ test, and a fresh DSM-5 rating from a clinician.
What they found
Clinicians leaned on IQ when they picked Level 1, 2, or 3. High IQ kids often got mild ratings even if their ADOS was high. Emotional or behavior problems barely changed the rating.
How this fits with other research
Barton et al. (2019) used the same SPARK set and showed those same IQ-tinged ratings decide who gets school help. High-IQ kids were less likely to receive services.
Hodge et al. (2021) and Amore et al. (2011) both found IQ, not autism severity, predicts adaptive skills. The pattern is clear: IQ keeps stealing the spotlight.
Tillmann et al. (2019) zoomed in on core social symptoms and found these—not IQ—drive real-life adaptive gaps. The trio of studies warns: when you let IQ color severity, you may under-serve bright kids and over-rate their daily skills.
Why it matters
Next time you assign or review a DSM-5 level, pause. Ask: “Am I rating social-communication and restricted behavior, or am I just writing down the IQ score?” Keep the two columns separate in your report. This small step keeps services, goals, and parent expectations tied to autism needs, not to test scores.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Open your last report: if the severity level and the IQ paragraph sound the same, add a sentence that links the rating to ADOS social-affect and RRB scores only.
02At a glance
03Original abstract
The newest edition of the Diagnostic and Statistical Manual of Mental Disorders (5th ed., DSM-5) introduced substantial changes to the diagnostic criteria for autism spectrum disorder, including new severity level ratings for social communication and restricted and repetitive behavior domains. The purpose of this study was to evaluate the use of these new severity ratings and to examine their relation to other measures of severity and clinical features. Participants included 248 children with autism spectrum disorder who received diagnostic evaluations at one of six Autism Treatment Network sites. Higher severity ratings in both domains were associated with younger age, lower intelligence quotient, and greater Autism Diagnostic Observation Schedule-Second Edition domain-specific symptom severity. Greater restricted and repetitive behavior severity was associated with higher parent-reported stereotyped behaviors. Severity ratings were not associated with emotional or behavioral problems. The new DSM-5 severity ratings in both domains were significantly associated with behavioral observations of autism severity but not with measures of other behavioral or emotional symptoms. However, the strong associations between intelligence quotient and DSM-5 severity ratings in both domains suggest that clinicians may be including cognitive functioning in their overall determination of severity. Further research is needed to examine clinician decision-making and interpretation of these specifiers.
Autism : the international journal of research and practice, 2019 · doi:10.1177/1362361318755318