'High Functioning' In Autism
Should We Discard The Term
Katherine K.M. Stavropoulos :
The term "high-functioning ASD" is typically used to describe individuals with ASD who have cognitive abilities in the average range. In terms of intelligence quotient (IQ), that usually means greater than or equal to 70 (average IQ is 100, with a standard deviation of 15). Individuals with IQ scores below 70 and daily living skill impairments are usually diagnosed with "intellectual disability" (ID), or what used to be called "mental retardation" (MR).
In light of the DSM-5 removing both Asperger's Syndrome and Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS), the term "high-functioning ASD" is sometimes used in place of those previous diagnoses to describe individuals with ASD who have average cognitive skills. The term "high functioning" is often thought to mean average (or above average) functional skills, and low levels of impairment in terms of day-to-day living.
However, recent research suggests that this term might be misleading, and in some cases may disqualify children and teens with ASD from receiving needed services. Spectrum News recently published a story about a large-scale research study on adaptive behavior in individuals with ASD. Adaptive behavior refers to daily living skills that people do independently (e.g., cleaning, showering, putting on clothing, etc). In most individuals without ASD, cognitive abilities (IQ) are highly correlated with adaptive behavior. Essentially, that means most individuals who have higher IQ scores are better at daily living/independent living skills than those with lower IQ scores. This difference in adaptive behaviors is particularly apparent when comparing individuals with and without an intellectual disability. It's not surprising, then, that there is an implicit assumption that individuals with "high functioning ASD" will have adaptive behaviors in the same range as their IQ scores (e.g. in the average range).
The new research study suggests that this assumption is incorrect. In a sample of over 2,000 individuals with ASD, they found that IQ was a weak predictor of adaptive behavior scores. There was a particularly large gap between IQ and adaptive behavior scores for individuals with ASD who had IQ scores over 70 (e.g., those who did not have an intellectual disability; ID). Though there was still a gap between IQ scores and adaptive behavior scores in individuals with ASD and ID, it was a smaller gap than observed for those without ID.
So, what do these results mean? Essentially, it means that we should not be using IQ as a proxy for adaptive behavior skills. We should not assume that just because a given individual with ASD has cognitive skills in the average range that he or she will automatically have adaptive behavior skills in that same range.
The next question is, why do these results matter? The results are important because of how services are allocated. In the U.S. (and in California, where I live), what services are provided to a given individual or their family is often determined by diagnosis and cognitive ability. For example, a child with a diagnosis of ASD who does not have intellectual disability (ID) would likely receive services for ASD-specific impairments (e.g., social-communication services), but not for impairments related to ID (e.g., adaptive behavior interventions or supports). Given the findings outlined above, this method of service allocation is problematic and may lead to some individuals receiving inadequate services.
Finally, how do these findings relate to the term, "high functioning"? If "high-functioning ASD" is based on cognitive abilities-as is often the case-it doesn't accurately capture the experiences, needs, strengths, or weaknesses of a given individual. Not only might this term limit supports or services for those who might need them, but it can also be inherently offensive to individuals who would be considered "low functioning."
What, then, are the next steps that should come out of this research? The authors do a great job of providing suggestions for clinicians and researchers moving forward. They suggest that researchers and clinicians should note different diagnoses or observable behavioral patterns that describe the day-to-day functioning and experience of those with ASD. Thus, rather than describing a teenage boy with ASD, fluent spoken language, and an IQ of 90 as "high functioning," we would say that he has ASD without an intellectual disability, has fluent verbal skills, and then describe whether he evidences impairments in adaptive behaviors or not. By moving away from the "high/low-functioning" labels, it forces all of us to use more accurate and nuanced descriptors, and these more accurate descriptors will be significantly more helpful in designing interventions and service allocation.
(Katherine K.M. Stavropoulos, Ph.D., is an assistant professor at UC Riverside and a licensed clinical psychologist).