Discovery of previously undetected intellectual disability by psychological assessment: a study of consecutively referred child and adolescent psychiatric inpatients.
Screen every child psychiatric inpatient with both IQ and adaptive measures—one in six had undetected intellectual disability.
01Research in Context
What this study did
The team looked at every child and teen admitted to a psychiatric hospital. They gave each one an IQ test and an adaptive-skills checklist.
They wanted to see how many kids had intellectual disability that no one had caught before.
What they found
One in six in-patients had an IQ below 70. Most of them also scored low on daily-living skills.
These kids had been in mental-health care, yet their ID stayed hidden until this test.
How this fits with other research
Coe et al. (1997) looked back at 233 charts and found the same pattern: many youths with ID were called behavior kids instead.
Matson et al. (2004) showed the flip side; they gave the PAS-ADD Checklist to adults already known to have ID and found 20% had mental-health symptoms. Together these papers form a circle: kids come in for behavior, get no IQ test, and leave with the wrong label.
Bigham et al. (2013) warns that parent checklists alone can over-call ADHD when ID is really the issue. The new data say: always add formal IQ and adaptive scores so you do not repeat the mistake.
Why it matters
If you work on an inpatient unit, build a two-step screen into intake: quick IQ estimate plus Vineland or ABAS interview. Catching ID early swaps vague behavior plans for real skill-teaching and saves months of failed psych meds. One extra hour of testing can reroute the whole case.
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02At a glance
03Original abstract
Intellectual disability is associated with an increased risk of behavioral disturbances and also complicates their treatment. Despite increases in the sophistication of medical detection of early risk for intellectual disability, there is remarkably little data about the detection of intellectual disability in cases referred for psychiatric treatment. In this study, we used a 10-year sample of 23,629 consecutive child and adolescent admissions (ages between 6 and 17) to inpatient psychiatric treatment. Eleven percent (n=2621) of these cases were referred for psychological assessment and were examined with a general measure of intellectual functioning (i.e., WISC-IV). Of these cases, 16% had Full Scale IQs below 70. Of the cases whose therapists then referred them for formal assessment of their adaptive functioning (i.e., ABAS-II) 81% were found to have composite scores below 70 as well. Only one of the cases whose Full Scale IQ was less than 70 had a referral diagnosis of intellectual disability. Cases with previously undetected intellectual disability were found to be significantly more likely to have a diagnosis of a psychotic disorder and less likely to have a diagnosis of mood disorder than cases with IQs over 70. Disruptive behavior disorder diagnoses did not differ as a function of intellectual performance. These data suggest a high rate of undetected intellectual disability in cases with a psychiatric condition serious enough to require hospitalization and this raises the possibility that many such cases may be misdiagnosed, the basis of their problems may be misconceptualized, and they may be receiving treatments that do not take into account their intellectual level.
Research in developmental disabilities, 2014 · doi:10.1016/j.ridd.2014.03.012