Several NHS integrated care boards (ICBs) in England have introduced minimum waiting times of up to two years for assessments of autism and attention deficit hyperactivity disorder (ADHD), reflecting mounting pressure on the health service from a significant rise in demand. This development affects millions of people and highlights the challenges faced by the NHS in managing growing referral volumes alongside financial constraints.
The decision to impose these extended waits has been attributed to the increasing number of people seeking neurodiversity diagnoses, which has led to a sharp rise in the cost of assessments. For example, the West Yorkshire ICB reported that its expenditure on such assessments more than doubled from £7 million in 2023-24 to £21 million the following year, prompting a restriction on assessment availability for the approximately 2.4 million people it serves. Similar measures have been adopted in other regions including the North East and North Cumbria, Somerset, Devon, Kent and Medway, and Hampshire and the Isle of Wight, with waits ranging from several months to nearly two years and priority criteria applied in some areas.
The backlog is stark: an estimated 960,000 people in England are waiting for ADHD assessments and 295,000 for autism assessments. This situation has driven many to seek private evaluations, which often come with high costs. Private providers currently conduct about half of NHS-funded ADHD assessments and one-third of autism assessments, partly due to patients exercising their legal right to choose non-NHS care when NHS waiting lists are prohibitively long. However, the new minimum waiting times imposed by some NHS bodies effectively limit this option, as patients must wait through these NHS-imposed delays before accessing private assessments funded by the NHS.
A recent government-commissioned review led by Professor Peter Fonagy has examined the rapid rise in diagnoses of autism, ADHD, and related mental health conditions over the past two decades. The unpublished 700-page interim report reveals a significant increase in prevalence, especially among boys aged six to 18. For instance, autism diagnoses in this group rose from 0.2% in 2000 to 4.7% in 2025, while ADHD diagnoses increased from 0.4% to 5.1% over the same period. The rise in referrals reflects greater clinical understanding, reduced stigma, increased public and institutional awareness, and system factors such as schools and the welfare system requiring formal diagnoses to access support.
The report also highlights challenges posed by the growing reliance on private sector providers, raising questions over consistency, quality, and potential financial incentives linked to assessments conducted outside the NHS. Additionally, the surge in demand puts pressure not only on health services but also on educational institutions, employers, and families.
Patient advocacy groups have condemned the extended waits as "heartless and dangerous," warning that delays may prevent timely access to critical support and treatment, particularly for children whose educational and social development might suffer. NHS officials acknowledge the deep frustrations caused by long delays and cite the need to balance budgets amid soaring demand. They emphasize that while local NHS leaders strive to address the problem, the current system is under unprecedented strain.
Professor Fonagy’s final report, expected in the coming weeks, is anticipated to offer recommendations on how to reform the assessment process to better meet demand while maintaining quality and accessibility. Meanwhile, the growing backlog and extended waits continue to expose significant gaps in the provision of care for individuals with autism and ADHD across England.