Mapping the age of autistic spectrum condition diagnosis, affected by sex and Intellectual disability

Abstract

Introduction/purpose: Autism is a complex neurodevelopmental condition thought to affect 1 in 100 children globally. More commonly diagnosed in males, and during childhood, diagnoses are increasingly being made throughout adulthood. Purpose: To establish what age autistic people receive their diagnosis, and whether the age of diagnosis was influenced by their sex and by the presence of intellectual disability. Design: A quantitative, cross-sectional, retrospective study. Data was collected from the Primary Care records of 6 GP Practices covering Ellesmere Port, a large town in Northwest England with 71,210 people registered. Mean age of diagnosis was calculated for the group then for each subgroup, to allow comparison between males and females, and those with and without a documented intellectual disability. Findings: Data from 1130 autistic participants were analysed. Age of participants was between 3 - 81 years with an age of autism diagnosis of 1 - 72 years. 85.6% of participants were diagnosed with autism by the age of 25 years, most commonly at 3 years of age (11.9%). The average age of diagnosis was 2.48 years later for females diagnosed across the lifespan. Average age of diagnosis was 5.05 years later for those with a learning disability. Practical implications: This study highlights the importance of healthcare professionals, educators and care givers recognising autistic traits in people across the lifespan, including the potential for diagnostic overshadowing. There are implications for commissioning autistic services, to ensure adequate assessment pathway capacity for adolescents and adults as well as children.