Your NHS ADHD Assessment Could Take Two Years: Why Experts Say the Wait Is Becoming a Health Risk

People seeking an ADHD or autism assessment through the NHS in parts of England could now face a minimum wait of up to two years, as health bodies introduce restrictions to manage rising demand and mounting costs.

Four NHS integrated care boards (ICBs) have introduced minimum waiting periods for ADHD and autism assessments, according to a Guardian investigation. A further 15 ICBs covering around 19 million people have introduced other measures to ration assessments, including limiting the number of assessments they will fund or prioritising people considered to have the most significant needs.

West Yorkshire NHS ICB has introduced a two-year minimum wait from referral for people seeking an ADHD or autism assessment through an independent provider. The policy applies across Leeds, Bradford, Kirklees, Calderdale and Wakefield, an area covering around 2.4 million people.

The restrictions have prompted concern from patient organisations, which argue that prolonged delays can prevent people from accessing support while they wait for a formal diagnosis.

Why Are ADHD Assessment Waits Increasing?

Demand for ADHD assessments has risen substantially in England in recent years.

NHS England estimated that up to 803,658 referrals that may relate to ADHD assessment were open in March 2026. Up to 32,375 new referrals were received that month, representing a 29.5% increase from March 2025.

The increase has placed significant pressure on specialist services, which must assess people against diagnostic criteria while also providing treatment and follow-up care for those who receive a diagnosis.

An independent ADHD Taskforce established by NHS England previously identified lengthy waiting times as a major problem. Its report found that some people were waiting more than two years for an assessment, with some areas reporting substantially longer delays.

The reasons behind rising demand are complex. Greater awareness of ADHD, people seeking assessment after being missed or misdiagnosed during childhood, changes in diagnostic practice and increased recognition that ADHD can persist into adulthood have all been identified as contributing factors.

Where Are Two-Year Minimum Waits Being Introduced?

West Yorkshire is among the areas imposing a two-year minimum wait.

The ICB said its spending on ADHD and autism assessments increased from £7 million in 2023-24 to £21 million the following year. It introduced the minimum wait as part of efforts to manage the cost of assessments commissioned from independent providers.

Other ICBs have introduced different thresholds. North East and North Cumbria has an approximately 78-week minimum wait for an initial assessment, while Somerset has introduced a 52-week minimum. Devon's minimum wait is 14 weeks. Kent and Medway has also decided to introduce restrictions.

Hampshire and the Isle of Wight has instead restricted ADHD and autism assessments to people who meet specific priority criteria.

Across the affected areas, the measures differ, but they have the same broader effect: some people referred for assessment are being required to wait longer before they can access an assessment funded by the NHS.

Why Can Delayed ADHD Diagnosis Matter?

An ADHD assessment is not simply a label. For someone who meets the diagnostic criteria, an assessment can provide access to treatment, workplace adjustments, educational support and other services.

ADHD is a neurodevelopmental condition characterised by persistent patterns of inattention and/or hyperactivity and impulsivity that interfere with everyday functioning. Symptoms can affect education, employment, relationships and daily organisation.

A diagnosis can also help clinicians determine whether someone may benefit from medication or other forms of support. However, not everyone who experiences difficulties with attention or impulsivity has ADHD, which is why a comprehensive assessment is important.

The NHS England ADHD Taskforce identified concerns about the consequences of prolonged waits, including worsening mental health, substance misuse and increased contact with the criminal justice system. The report also highlighted substantial gaps between the number of people estimated to have ADHD and those receiving diagnosis and treatment.

These risks do not mean that every person waiting for an assessment will experience deterioration. Individual circumstances, existing support and the severity of symptoms can all influence what happens during a delay.

Why Are Patient Groups Calling the Delays a Health Concern?

ADHD UK has strongly criticised the introduction of minimum waiting periods. Its chief executive, Henry Shelford, described the two-year minimum waits as 'heartless and dangerous', arguing that delayed assessment can prevent people from accessing support that may help them remain in education, employment and appropriate care services.

Other organisations have also raised concerns about the growing reliance on private providers and the financial burden placed on families who can afford to seek an assessment outside the NHS.

The Guardian reported that around 960,000 people in England were waiting for an ADHD assessment, alongside approximately 295,000 waiting for an autism assessment. Private providers now conduct a substantial proportion of NHS-funded assessments, increasing the importance of the NHS's 'Right to Choose' pathway for eligible patients.

The situation also raises a wider question about how diagnostic services should respond to rapidly increasing demand. A government-commissioned review led by clinical psychologist Professor Peter Fonagy has been examining the prevalence of ADHD, autism and mental health conditions, as well as how people access support.

NHS England's existing evidence indicates that the pressure is not simply the result of people requesting assessments. The health service is dealing with a combination of increased referrals, limited specialist capacity, financial constraints and longstanding gaps in diagnosis and treatment.

For people awaiting an assessment, the practical impact can therefore extend beyond the length of the queue. The longer the delay, the longer some individuals may remain without a formal explanation for difficulties affecting school, work, relationships or daily life.

At the same time, a diagnosis should not be treated as the only route to support. The appropriate help depends on an individual's circumstances, symptoms and needs, and some educational, workplace or mental health support may be available without a confirmed ADHD diagnosis.

The growing use of minimum waits nevertheless highlights the pressure facing NHS neurodevelopmental services and the challenge of providing timely assessments as demand continues to rise.