Specialist ADHD services for adults are stopping taking on new patients as they struggle to cope with demand, a BBC investigation has shown.
The BBC has identified 15 local areas that have closed waiting lists and another 31 that have introduced tighter criteria, making it more difficult to access support.
Reacting to our investigation, Prof Anita Thapar, chair of NHS England's ADHD taskforce, said the findings were "disturbing", adding there were "enormous risks" for patients.
It comes as she prepares to publish her report into the state of ADHD services on Thursday, which is expected to recommend an overhaul of the way people are supported.
ADHD - attention deficit hyperactivity disorder - affects the way the brain works and can cause people to act impulsively and become easily distracted.
It is thought to affect 5% of children and 3-4% of adults, although many remain undiagnosed.
Getting a diagnosis and treatment, which can include medication and psychological therapy, can be life-changing, experts say.
And now a BBC investigation has found a significant number of areas are restricting access to those waiting lists.
The BBC received information from 59 services, which accounts for the majority of those providing support in England, after submitting freedom of information requests.
The responses showed:
15 trusts had halted all or part of their referrals - some cover large areas and have closed their waiting lists to just some places
In Cheshire, the service for adults has been closed to new patients since 2019
Of the remaining trusts, 31 were rationing care by bringing in exclusions, such as by age or severity
One trust, Coventry and Warwickshire Partnership Trust, is being threatened with legal action for restricting adult assessments to people under 25 only
In some areas, people referred for support by GPs can use something called 'right to choose' to go onto another NHS list or ask for private support, which would provide an alternative option if their local NHS has stopped taking on new referrals.
The BBC investigation also found examples of areas that are innovating. One of those is Surrey where the local service, which has 11,000 adults on its waiting list, is piloting a scheme to train a group of private GPs to carry out assessments and treatment.
Louise has been waiting years for an assessment for ADHD
Louise Nichols, who suspects she has ADHD, is just one of many people affected by the rationing.
Even when she was at primary school she struggled. She was diagnosed with school phobia and ended up being home schooled for a while, and has since found it hard to stay in a job.
The mother-of-one says it is frustrating to see everyone else managing, while she finds daily life hard.
"I need a way of helping me function to the best of my abilities. Whether that's medication or whether that's support," she says.
"I'm hoping to get a part-time job. I want to be part of my community."
The 45-year-old lives in Derbyshire, but as this area does not have its own service, she was on the waiting list with the neighbouring Sheffield trust for two years.
But she was taken off that list in October last year because Sheffield stopped doing assessments for people who live outside their borders, as it's struggling to keep up with demand. There are more than 3,700 people in the county in the same position.
She said it was really disappointing. "I can't understand why a national health service isn't across the whole nation. "
Patients at risk
Prof Thapar said the problems being encountered by people like Louise were unacceptable and showed the "historic neglect" of ADHD by the NHS.
She called the BBC's findings "disturbing", adding: "There's enormous risks. It's not a trivial condition."
With the right support, she said people with ADHD can thrive, but there were "high, high risks" that without that support, people's conditions can become much more complicated.
This, she said, can include mental health problems, substance misuse, unemployment and getting in trouble with the criminal justice system.
And Dr Jessica Eccles, of the Royal College of Psychiatrists, said services were having to make difficult decisions because "rising demand was outstripping capacity" in many parts of the country.
"There are unacceptably long waiting lists," she added.
'Diagnosis transformed my life'
Sam's life has been transformed by getting his ADHD diagnosis
Patients who have received support say it has transformed their lives.
Sam Stone is an example of that, but he had to battle to get help.
The 33-year-old, who lives near Gloucester, paid for a private diagnosis on his health insurance, but his GP wouldn't accept it and he had to go back on an NHS waiting list to get it confirmed.
He is angry at how complicated the system is. "I almost struggle to think about it as a system, to be honest, because it feels like there's such a cacophony of routes that it almost feels like you're constantly trying to hack the system."
Sam said the diagnosis has been life-changing. He had been on and off anti-depressants since the age of 16, but he is now on medication for his ADHD.
He said it was like having a cloud hanging over him removed.
"It's massive, it's huge," Sam says.
Additional reporting by Elena Bailey and data analysis by Rob England
Fatima Bosch said Nawat Itsaragrisil was "not respectful" at a pre-pageant ceremony on Tuesday
Several contestants have walked out of a Miss Universe event after an official from host nation Thailand publicly berated Miss Mexico in a tense confrontation.
At a pre-pageant ceremony, Miss Universe Thailand director Nawat Itsaragrisil told off Fatima Bosch in front of dozens of contestants for failing to post promotional content.
When she objected, Mr Itsaragrisil called security and threatened to disqualify those supporting her. Ms Bosch then left the room and others joined her in solidarity.
Video of the incident, which was live streamed, has been shared online. The Miss Universe Organisation (MUO) has condemned Mr Itsaragrisil's "malicious" behaviour, for which he has since apologised.
The Miss Universe contestants, who are the winners of national pageants in their home countries, attended Tuesday's event in their sashes and gowns.
Some can be heard shouting back at Mr Itsaragrisil in the video, after he raises his voice to reprimand Ms Bosch and repeatedly tells her to stop talking.
As many of them stand to show support, Mr Itsaragrisil says: "If anyone wants to continue the contest, sit down. If you step out, the rest of the girls continue."
Despite this, the majority of the women in the video appear standing, with several heading towards the door.
After leaving the event on Tuesday, Ms Bosch told the press the 60-year-old executive was "not respectful" and said he had called her "dumb".
Mr Itsaragrisil has disputed this, claiming his words had been misunderstood.
He is widely reported to have called the 25-year-old a "dumbhead". But at a press conference he later claimed he was saying she had caused "damage".
His conduct prompted a stern rebuke from the MUO, which has sent a delegation of international executives to take over running the competition.
In a video statement, MUO President Raul Rocha said Mr Itsaragrisil had "forgotten the true meaning of what it means to be a genuine host".
He said the Thai official had "humiliated, insulted and showed a lack of respect" to Ms Bosch, and committed the "serious abuse of having called security to intimidate a defenceless woman".
Mr Itsaragrisil's participation in the pageant would be limited "as much as possible" or eliminated entirely, he said, adding the MUO would be taking "legal actions" against him.
"I wish to reiterate that Miss Universe is an empowerment platform for women so that their voices can be heard in the world," Mr Rocha said.
RUNGROJ YONGRIT/EPA/Shutterstock
Thai businessman and media personality Nawat Itsaragrisil has apologised for the incident
Among those to walk out on Tuesday was reigning Miss Universe Victoria Kjaer Theilvig of Denmark.
"This is about women's rights," she said as she left the event. "This is not how things should be handled. To trash another girl is beyond disrespectful... That's why I'm taking my coat and I'm walking out."
Ms Bosch later said in an interview: "I just want to let my country know, I'm not afraid to make my voice heard. It's here stronger than ever. I have a purpose. I have things to say.
"We're in the 21st century. I'm not a doll to be made up, styled and have my clothes changed," she added.
"I came here to be a voice for all the women and all the girls who fight for causes and to tell my country that I'm completely committed to that."
Video of Mr Itsaragrisil has outraged fans of the pageant, with many heavily criticising his actions and praising Ms Bosch's response.
In a social media video statement, Mr Itsaragrisil said: "If anyone feels bad, uncomfortable, or affected, I apologise to everyone. I especially apologised to the girls who were present, around 75 of them."
The Miss Universe competition has pressed on despite this controversy, with contestants taking part in a welcome event in Bangkok on Wednesday.
The winner will be crowned the new Miss Universe on 21 November.