The misnomer of ‘high functioning autism’: Intelligence is an imprecise predictor of functional abilities at diagnosis

Abstract

‘High functioning autism’ is a term often used for individuals with autism spectrum disorder without an intellectual disability. Over time, this term has become synonymous with expectations of greater functional skills and better long-term outcomes, despite contradictory clinical observations. This study investigated the relationship between adaptive behaviour, cognitive estimates (intelligence quotient) and age at diagnosis in autism spectrum disorder. Participants ( n = 2225, 1–18 years of age) were notified at diagnosis to a prospective register and grouped by presence ( n = 1041) or absence ( n = 1184) of intellectual disability. Functional abilities were reported using the Vineland Adaptive Behaviour Scales. Regression models suggested that intelligence quotient was a weak predictor of Vineland Adaptive Behaviour Scales after controlling for sex. Whereas the intellectual disability group’s adaptive behaviour estimates were close to reported intelligence quotients, Vineland Adaptive Behaviour Scales scores fell significantly below intelligence quotients for children without intellectual disability. The gap between intelligence quotient and Vineland Adaptive Behaviour Scales scores remained large with increasing age at diagnosis for all children. These data indicate that estimates from intelligence quotient alone are an imprecise proxy for functional abilities when diagnosing autism spectrum disorder, particularly for those without intellectual disability. We argue that ‘high functioning autism’ is an inaccurate clinical descriptor when based solely on intelligence quotient demarcations and this term should be abandoned in research and clinical practice.

The adult outcome of children referred for autism: typology and prediction from childhood

“…It is important to note that predictive IQs at preschool were not high in terms of absolute scores (Table 1); IQ scores for the Best Outcome class were below average during most of the preschool years, but showed steady increases throughout childhood, only reaching above average IQ scores in adulthood. Alvares et al (2020) highlight the imperfect relationship between IQ and contemporaneous functioning as measured by the VABS, especially for those without ID, and that IQ alone is an inadequate basis for defining 'high-functioning autism'. Nonetheless, for long-term prognosis from childhood, IQ seems to be our best predictor even of an outcome typology that excludes IQ.…”

Avoiding Ableist Language: Suggestions for Autism Researchers

“…Thus, ideologies evidenced in everyday and institutional discourse are assumed to both establish and maintain power relationships. 42 Disrupting dominant discourses about autism, primarily controlled by those in positions of power, is therefore necessary to change 99 Areas of interest or areas of expertise, focused, intense, or passionate interests Special needs 98,100,101 Description of specific needs and disabilities Challenging behavior/disruptive behavior/problem behavior 7,37,102,103 Meltdown (when uncontrollable behavior), stimming (when relevant), specific description of the behavior (e.g., selfinjurious or aggressive behavior) Person-first language (to refer to autism) 8,17,65,72,[104][105][106][107] Identity-first language; ''on the autism spectrum'' Medicalized/deficit-based language High/low functioning; high/low severity or support needs 9,17,84,85 Describe specific strengths and needs, and acknowledgment that the level of support needs likely varies across domains (e.g., requires substantial support to participate in unstructured recreation activities, but minimal support to complete academic work) ''At risk'' for ASD 73 Increased likelihood/chance of autism Burden of/suffering from autism 108 Impact, effect Co-morbid 109,110 Co-occurring Autism symptoms 17 Specific autistic characteristics, features, or traits Treatment Support, services, educational strategies (when applicable) Healthy controls/normative sample 111,112 Nonautistic (if determined via screening), neurotypical (if determined via extensive screening ruling out most forms of neurodivergence), comparison group (with description of relevant group characteristics) Psychopathology 98 Neurodevelopmental conditions, neuropsychiatric conditions, developmental disabilities, mental illnesses (or specific mental health condition) Ableist discourses: ways of discussing autism not relegated to the use of particular terms, that reflect and/or contribute to dehumanization, oppression, or mar...…”

“…9 For example, autistic people without ID more often experience a dropoff in services following high school, whereas those with ID are more likely to transition into a supported context (e.g., supported employment, organized daytime activities). 82,83 Recent empirical research supports these criticisms; measures of adaptive functioning do not correlate with measures of intellectual ability in autistic children, 84 and the divergence between these two domains tends to increase with higher age and IQ scores. 85 Functioning labels are therefore not only inaccurate, but they can also result in situations where autistic people labeled ''high functioning'' are not provided with the supports they need, while autistic people labeled ''low functioning'' are underestimated in regard to their actual capabilities.…”

Developing Employment Environments Where Individuals with ASD Thrive: Using Machine Learning to Explore Employer Policies and Practices

“…This term was used to provide a brief descriptor of a particular group of individuals with ASD (i.e., those with average to above-average cognitive skills). However, the term HFASD can be problematic, as the term suggests those with average or above cognitive skills perform well in other functional areas, while the evidence indicates this is a poor predictor of functional skills [51]. To ameliorate some of these concerns, while still maintaining a "short descriptor", investigators clearly defined what was meant by HFASD as it related to the survey.…”