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 Adaptiv..