Autism prevalence in school children in Southeast England: Findings from a cross-sectional survey

Abstract Background Over the past 3 decades, there has been a substantial and sustained increase in the reported prevalence of autism in children in Europe. Prevalence estimates are largely based on confirmed diagnosis; however, research suggests that many children exhibiting autistic traits are not undergoing the diagnostic process. This potential under-ascertainment has important implications for service planning in education and healthcare, and for the overall health/wellbeing of affected children. We conducted a cross-sectional survey of schools in Southeast England to ascertain the prevalence of diagnosed/undiagnosed autism. Methods A questionnaire was sent to the Special Educational Needs Coordinators (SENCo) in 21 schools in Southeast England. This included information on sociodemographic variables, clinical diagnosis, and children exhibiting traits of autism and/or neurodevelopmental conditions. Results Information was obtained on 12,309 children aged 5-16 years; of these, 432 (3.5%) had a clinical diagnosis of autism and 352 (2.9%) were suspected by the SENCos to have the condition, 1057 (8.6%) had a diagnosis of a neurodevelopmental condition and 2092 (17%) were registered as having additional needs. With regards to age, 4.1% (197/4780) of children aged 5-10 years and 3.1% (235/7529) of children aged 11-16 years had a clinical diagnosis of autism. Conclusions These findings suggest that for nearly every child with a clinical diagnosis of autism, there is another who is suspected of being autistic but remains undiagnosed. This indicates that many children who may benefit from early diagnosis and support are not currently identified due to prolonged waiting times for clinical assessment. Considering that delayed diagnosis of autism can significantly impact a child's development and overall well-being, there is need for strengthening awareness, expanding/resourcing diagnostic pathways, setting targets for diagnosis waiting times and ensuring timely access to support. Key messages • Tackling delayed diagnosis of autism requires a system-wide response and integrated approach that bridges health and education, streamlines diagnostic pathways, and actively addresses inequality. • Understanding true extent of autism prevalence, which is influenced by diagnostic practices, healthcare access and awareness, is important for informing policy, resource allocation and interventions.