The health service is now spending ten times more money on diagnosing ADHD than it was a year ago - a costly bill that NHS leaders have deemed 'out of control' and 'unsustainable'. Private clinics are also taking advantage of soaring demand, charging the NHS up to £3,000 per patient to carry out assessments for ADHD and autism, health chiefs say.As a result, some regions are being forced to scale back on vital services for people with learning disabilities to meet soaring demand for ADHD assessments, according to a new report.The NHS Alliance, which represents health trusts and published the report, said the current system is 'out of control' and represented a 'bad deal' for patients and taxpayers alike. The group added that NHS managers are struggling to ensure the quality and safety of care being provided, after examining the 'relentless rise' in spending across the 42 NHS care boards. Referrals for ADHD have soared 20-fold since the turn of the century, NHS figures show. Currently, there are 800,000 people waiting for an ADHD assessment in England. NHS England also estimates that around 2.5 million people in England are living with ADHD, including many who have not yet been formally diagnosed. Under an initiative known as the Right to Choose, patients can be assessed privately, with the NHS then obliged to foot the bill, driving the dramatic surge in spending. Autism and ADHD care is at risk of descending into chaos, NHS bosses have warnedOne unnamed integrated care board (ICB) told the NHS Alliance its monthly spending on ADHD and autism services had risen more than tenfold, from £146,000 in 2024-25 to £1.5 million last year. In Kent and Medway, spending on the assessment and treatment of ADHD and autism rose from less than £1 million in 2023-24 to an eye-watering £28.9 million this year. Meanwhile, in Cheshire and Merseyside, spend on adult ADHD services alone has soared from £11million in 2023-24 to a projected £51million for the 2026-27 financial year. The NHS Alliance's report highlighted 'huge variation' in the prices paid for services, with fees ranging from £300 to £3,000 for an initial assessment. A Government review into what is driving the rising demand - including an inquiry into whether the increase reflects overdiagnosis - is expected to be published soon. The Right to Choose initiative is aimed at helping patients bypass long waiting lists, but the NHS Alliance said the policy has led to a 'Wild West' of private clinics - many of which are carrying out diagnostic assessments online. One unnamed trust said it received invoices for ADHD services from 80 separate clinics. 'The current situation is unsustainable and delivers a bad deal for patients and taxpayers,' Rebecca Gray, director of the alliance's mental health network said. Actress Sheridan Smith has spoken about how a diagnosis of attention deficit hyperactivity disorder (ADHD) has helped her 'make sense of a lot of things' in her life.