To ID or not to ID? Changes in classification rates of intellectual disability using DSM-5.
DSM-5’s single-domain adaptive rule quietly cuts the ID caseload by nine percent—double-check scores before you drop the diagnosis.
01Research in Context
What this study did
The team asked: how many kids lose the ID label under new DSM-5 rules?
Old rules needed low IQ plus problems in two adaptive areas. DSM-5 needs low IQ plus problems in only one area.
They re-checked records for a mixed clinical sample and counted who still qualified.
What they found
Nine percent fewer children met ID criteria under DSM-5.
In plain words, one in every eleven kids once called ID no longer fits the diagnosis.
How this fits with other research
Coo et al. (2008) saw the same 9-point drop in British Columbia schools when autism codes rose and MR codes fell.
Williams et al. (2002) found an almost identical swap in California: autism up 9 per 10,000, MR down 9 per 10,000.
These papers do not clash. They all show that when the rules tighten, the diagnosed group shrinks, whether the label is ID or autism.
Why it matters
Your re-evaluations may drop kids below the ID cutoff. Check adaptive scores in every domain before you change a label. A lost ID tag can cost a child waiver funds, school placement, or therapy hours. Keep the old report handy to justify continued services if the client still needs them.
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02At a glance
03Original abstract
The Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition (DSM-5) diagnostic criteria for intellectual disability (ID) include a change to the definition of adaptive impairment. New criteria require impairment in one adaptive domain rather than two or more skill areas. The authors examined the diagnostic implications of using a popular adaptive skill inventory, the Adaptive Behavior Assessment System-Second Edition, with 884 clinically referred children (ages 6-16). One hundred sixty-six children met DSM-IV-TR criteria for ID; significantly fewer (n = 151, p = .001) met ID criteria under DSM-5 (9% decrease). Implementation of DSM-5 criteria for ID may substantively change the rate of ID diagnosis. These findings highlight the need for a combination of psychometric assessment and clinical judgment when implementing the adaptive deficits component of the DSM-5 criteria for ID diagnosis.
Intellectual and developmental disabilities, 2014 · doi:10.1352/1934-9556-52.3.165