Why are so many adults now being diagnosed with ADHD? We take an in-depth look at the condition 

Could an epidemic of attention deficit hyperactivity disorder (ADHD) be afflicting Britain’s adult population?

Or are many instead being over-diagnosed with the condition and even put on drugs that in the long term may diminish their mental abilities and increase their risk of serious illnesses such as brain disorders?

A spotlight’s been thrown on ADHD this month after comedian Johnny Vegas, 52, became the latest in a wave of celebrities to announce they have been diagnosed with ADHD (others include comedian Rory Bremner, chef Heston Blumenthal and TV presenters Ant McPartlin and Sue Perkins).

Johnny Vegas told BBC Breakfast: ‘Everybody has an element of ADHD. But it’s about how strong your filter is. When you don’t have a filter at all, simple things become time-consuming.

‘I’ll think, I’ll shift that cup, and then you have ten other ideas and you haven’t shifted that cup. Three weeks later it’s become this monumental task.’

In yesterday’s Mail, Inspire columnist Dr Clare Bailey described her own experiences with ADHD.

ADHD is a serious, complex neurobiological condition characterised by inattentiveness — such as having a short attention span, being easily distracted, appearing forgetful or losing things — and impulsivity, for instance, being unable to sit still and concentrate.

As many as one in 20 adults in Britain has the condition, according to the charity ADHD Foundation, but only 120,000 have had a formal diagnosis — the charity said this is because of a ‘combination of poor understanding of the condition, stigma and delays in diagnosis’.

Yet growing diagnosis levels among adults are causing alarm among some UK experts. Joanna Moncrieff, a professor of critical and social psychiatry at University College London, told Good Health: ‘Diagnoses of adult ADHD are running rampant now.’

She is particularly concerned that screening tools for ADHD are too lax, meaning too many people are simply ‘diagnosing’ themselves.

As an illustration, the ADHD Foundation’s online self-assessment includes questions such as, ‘How often do you have difficulty keeping your attention when doing boring or repetitive work?’ and ‘How often do you make careless mistakes when you have to work on a boring or difficult project?’ Many of us might readily answer ‘Yes, often’ to those.

Other questions suggest that people may have adult ADHD if they often ‘misplace or have difficulty finding things at home or work’, are ‘distracted by noise or activity’ or ‘have difficulty wrapping up the final details of a project, once the challenging parts have been done’. Again, these may seem like everyday experiences for many of us.

Meanwhile, there has also been a surge in videos and posts on social media websites claiming to help people spot the signs of ADHD, again with broad-ranging symptoms so everyone could think they had ADHD — and should you have ADHD, you can then sign up for ‘support’, or perhaps pay for an online course.

TikTok videos with the hashtag #ADHD, which have been viewed 20.2 billion times, include one that sets out ‘six signs you may have adult ADHD’ — these include losing interest in hobbies, always being late and ‘scrolling TikTok and ignoring texts’.

On Instagram, meanwhile, one ADHD expert describes how chronic constipation can be a symptom. Someone comments: ‘I would never have made that link.’ That’s possibly because none of these symptoms features in the official diagnostic criteria.

ADHD is defined in the psychiatrists’ bible, the Diagnostic and Statistical Manual (DSM), quite strictly.

For an adult to be diagnosed with ADHD, the DSM dictates that they must have at least five symptoms of inattention (such as poor organisation and being easily distracted) and/or at least five symptoms of hyperactivity/impulsivity (such as difficulty engaging in quiet, leisurely activities, blurting out answers) for six months or more ‘to a degree that is inconsistent with the developmental level and negatively impacts social and academic/occupational activities’.

The DSM also says several ADHD symptoms should have been noted as present before the age of 12.

Professor Moncrieff worries that celebrities who say they have ADHD effectively act as a fashionable endorsement for the condition, and that people see others with the condition and simply decide they have it, too.

She says: ‘If you should want a diagnosis, you can get a diagnosis. The diagnostic questionnaires are so simplistically obvious that people know which are the right answers to give to get a diagnosis of adult ADHD.’

Her concern is echoed by a study in the Canadian Journal of Psychiatry in 2015 from McGill University. It warned that the condition is being seriously over-diagnosed, due not least to the use of simplistic symptom checklists, and said ‘over-diagnosis leads to over-treatment, and dramatic increases in prescriptions for adult ADHD during the last decade should arouse concern’.

Professor Moncrieff adds that there are concerns surrounding drugs used to treat ADHD — specifically, increasing numbers of British adults are being put on amphetamine-type drugs as a first-line treatment.

Four stimulant drugs are licensed in the UK for reducing symptoms of ADHD: methylphenidate, lisdexamfetamine, dexamfetamine and guanfacine.

These medications are intended to boost adults’ ability to concentrate and focus on completing tasks.

Giving someone who feels impulsive and scatty a stimulant drug might seem an odd thing to do, but the NHS says stimulants work ‘by increasing activity in the brain, particularly in areas that play a part in controlling attention and behaviour’.

Professor Moncrieff is sceptical. ‘Stimulants are quite pleasant to take, so people will think that they feel and function better when taking them,’ she says.

‘But that doesn’t mean that people actually are. There is no evidence that taking these stimulants actually makes you better at passing exams or better at driving a car.’

Indeed, a 2010 review in the journal Neuroscience & Biobehavioral Reviews concluded that students who take the stimulant drugs do not show improved learning or academic achievements.

Lead researcher Claire Advokat, a professor of psychology at Louisiana State University, warned that drugs such as methylphenidate may instead dull people’s mental impulses and reduce their cognitive flexibility. Heston Blumenthal was prescribed the amphetamine-based ADHD drug Adderall when diagnosed three years ago — but last week said he had stopped taking it as he ‘was constantly fretting over whether the drugs would dampen my imagination’.

Other people complain of other medication-related problems. Last September, a survey of nearly 600 adults with ADHD found that nearly half said their medications caused sleep disturbances, depressed mood and panic attacks, reported the journal Current Medical Research and Opinion. And 45 per cent said the drugs increased their emotional impulsivity and mood swings.

The report concluded that ‘symptoms associated with ADHD treatment-related side-effects are common and have a substantial negative impact on quality of life and reduce chances of employment’.

Harmful physical side-effects are also being reported following long-term use. For example, a report by the expert website WebMD, says ADHD drugs ‘can raise blood pressure and speed up heart rate. If you already have an issue with your heart, these medicines could be risky’.

Professor Moncrieff fears that the drugs may also cause neurological damage. ‘The long-term effects of stimulant drugs prescribed for adult ADHD are under-researched,’ she says. ‘But there is worrying evidence emerging that taking prescribed stimulants increases the risk of developing Parkinson’s disease.’

A 2015 study in the journal Frontiers In Human Neuroscience warned that taking the drugs at levels commonly prescribed for ADHD may lead to people developing symptoms of Parkinson’s — after animal studies showed the drugs can have a toxic effect on brain cells.

Furthermore, a 2008 study of animals given prescription-levels of these stimulants showed disruption to their brains’ dopamine systems after only four weeks of taking the medication.

The study in the journal Molecular Psychiatry warned that ‘dysfunction of dopamine plays a role in Parkinson’s and mental disorders such as schizophrenia’, not least because it is linked with a loss of emotional regulation.

Long-term use of ADHD drugs may even, ironically, make it harder to concentrate, according to a review in the journal Neuropsychiatric Disease and Treatment in 2016.

The researchers said that methylphenidate prompts human brains effectively to resist the drug’s effects and ‘results in increased inattention and the need for an increase in the dose administered’.

Professor Moncrieff says: ‘It’s really worrying that we are giving out these stimulants where we don’t know what the implications are for people taking them for long periods.

‘It is not clear either that stimulant treatment helps,’ she adds. ‘Given the risky side-effect profile of these drugs we should be questioning our current fast-growing trend for diagnosing and drugging adults for ADHD.

‘But it’s difficult to argue against because the UK authorities say that we should prescribe stimulants.’

There is an argument over whether adult ADHD is actually a condition or a character trait that can prove problematic in a modern world that demands that many of us make our livings by sitting calmly at desks doing focused work. ‘I believe that adult ADHD isn’t as much a pathology as an aspect of temperament or character,’ says Professor Moncrieff. ‘Some people are more distractible than others. I think it’s pretty rare, about 1 per cent of patients, where I’d feel comfortable saying that these traits are severe and problematic for them.’

Other experts disagree, and say that adult ADHD is under-diagnosed and under-treated. Dr Blandine French, a research fellow at Nottingham University who studies neuro-developmental disorders such as ADHD, told Good Health: ‘Yes, there are more ADHD diagnoses, especially in adults — but this is because so many have been unrecognised for years.

‘The recognition of ADHD as a diagnosis has become better but we are still far from recognising everyone in the UK with it.’

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