Zopiclone is the so-called 'safer' sleeping pill dished out by doctors to millions of Britons each year.
When it was launched in the 1990s, it was touted as a user-friendly alternative to older and notoriously addictive tranquillisers.
And in the short-term, zopiclone causes few problems. Indeed, it can be a lifeline to those battling the agony of sleeplessness.
But there are growing concerns, and mental health experts now warn that the drug could be just as risky as older tablets and can trigger severe withdrawal symptoms that make it impossible for patients to stop taking it.
Support workers and sufferers, speaking to this newspaper, have described a raft of disturbing symptoms linked to long-term use of zopiclone, many of which begin as soon as a dose is missed.
These include crushing anxiety and agoraphobia, flu-like aches and pains and distressing digestive problems.
Zopiclone is the so-called 'safer' sleeping pill dished out by doctors to millions of Britons each year. Pictured: Stock image
Studies indicate that patients may even have suicidal thoughts.
Professor Joanna Moncrieff, author of several books on psychoactive drugs, said: 'Zopiclone was originally meant to be a safer version of benzodiazepine medicines, but it's become obvious it is not.'
Benzodiazepines include, among others, tramadol, given for sleep, and Valium, or diazepam, which is mainly an anti-anxiety medicine.
Widely prescribed from the late 1950s, they became associated with dependence, severe withdrawal symptoms, worsening mental health and other problems. Zopiclone was supposed to be different.
It has become the most commonly taken member of the family of 'Z' drugs, which includes zolpidem, also known by the US brand name Ambien.
Like benzodiazepines, Z drugs work by boosting levels of a chemical messenger in the brain called gamma-aminobutyric acid, which produces a feeling of calm and drowsiness.
There were initial suggestions they weren't as addictive and had fewer downsides, even when used longer term.
Last month it was reported that a number of Premier League footballers were hooked on zopiclone and zolpidem.
Team doctors had originally prescribed the drugs to help players sleep before midweek matches, but it was claimed some were mixing the medication with alcohol to increase its effect.
Ian Govendir (seen above) has been unable to break his addiction to zopiclone
It is a dangerous game: the combination of sleeping pills and alcohol can be deadly.
There were 539 deaths from sleeping pills, including Z drugs, in 2019, of which 139 were linked to alcohol. This is twice the number of such incidents in 2009.
Professor Owen Bowden-Jones, a consultant psychiatrist for Central and North West London NHS Foundation Trust, said: 'We have seen people from 15 years old to pensioners, from every walk of life, addicted to Z drugs.'
The NHS bill for sleeping pills now stands at £10 million a year, and in 2020 more than 14 million prescriptions were given out for zopiclone alone.
This is, perhaps, unsurprising as insomnia – broadly defined as long-term problems getting to or staying asleep – is incredibly common, believed to affect between ten and 30 per cent of the population.
The drugs watchdog, the National Institute for Health and Care Excellence, suggests that sleeping pills should be prescribed only in cases of severe insomnia and for between two and four weeks.
Yet recent research suggests more than 300,000 Britons have been on a Z drug or other sleeping pill for a year or longer.
Melanie Davis, of addiction recovery charity Change Grow Live, says: 'Patients manage fairly well on zopiclone to begin with, but the pills stop working after a year or so and they start taking higher doses.
'The drug can cause side effects – drowsiness, poor concentration, a low or flat mood and even amnesia. But the biggest problems arrive when people try to come off it and get hit by withdrawal symptoms.
They can be worse than we see with illegal drugs: panic attacks and severe, unrelenting anxiety, flu-like symptoms and cramps. Some people say their body feels like jelly.'
If a patient is dependent on zopiclone, doctors are now advised not to pressure them to stop straight away but instead will reduce their dose gradually. However, this process may take months, or longer.
It's a painful process that 60-year-old Ian Govendir knows all too well – he is unable to quit zopiclone, having been first prescribed it almost two decades ago.
The charity boss says: 'My partner at the time worked in the hotel business, which meant getting up at ungodly hours.
'I'd never been a great sleeper but the disturbance made it impossible, and I felt constantly tired and grouchy at work.
'I went to my doctor, told him I'd been having trouble sleeping and he prescribed zopiclone. I didn't think it was anything unusual, to be honest.'
Support workers and sufferers have described a raft of disturbing symptoms linked to long-term use of zopiclone, many of which begin as soon as a dose is missed. Pictured: Stock image
The drugs worked, and Ian began sleeping well. He adds: 'I carried on taking them every night for about a year, until that relationship ended.
At that point I knew I wasn't going to be disturbed at night, so I stopped, and that was it. After that, I had no difficulty getting to sleep without them.'
In 2017, the combination of a stressful house move, family illness and demanding work travel meant Ian began struggling to sleep again.
'I was travelling internationally every six weeks for charity work,' he says.
'There was a period where I flew to Africa, Australia, Malaysia and the States in quick succession. My body clock became completely messed up.'
By the time he visited his GP, Ian admits: 'I was on the floor, physically and emotionally. I had another trip coming up and told my doctor there was no way I could cope without sleeping pills. He prescribed me a one-month supply, even though my trip was just two weeks.
'When I got back I carried on taking the pills, and my doctor kept giving me prescriptions. There was no discussion about side effects or withdrawals. If I wasn't travelling there were the everyday stresses, and I didn't want to risk not sleeping on top of those.
'I had every intention to stop taking them at some point, but I just didn't.
'There were side effects. Although the pills make you sleep, it's not proper sleep. So you go about feeling tired and in a sort of fog.
'But it just seemed better than the alternative, which was not sleeping.
'After about 18 months the pills stopped working so well, so without telling my doctor I began taking two rather than the recommended one. That was when I realised I might have a problem.'
Covid Q&A: Is it jabs or lockdown helping, and am I safe in a pub garden?
Have cases fallen because of the national lockdown or because of the vaccine rollout?
Lockdown has been the biggest driving force behind the fall in Covid cases, but vaccines have helped too.
On Wednesday, commentators questioned Prime Minister Boris Johnson's assertions that lockdown restrictions had done 'the bulk of the work' in reducing the disease.
But analysis of the data shows this to be largely true.
The decline in cases since the peak in early January has followed roughly the same trajectory as the fall in cases during the first wave, when there were no vaccines.
What's more, at the point at which cases began to decline across all ages in early January, vaccinations were being offered to only the over-80s.
Even now, cases have plummeted in the under-60s, even though only one in every three people in this age group have had one vaccine dose.
But for those over 60, there are clear signs that the vaccines have led to a marked decline in cases.
Since the beginning of March, cases in over-60s have fallen at a faster rate than in the under-60s.
As increasing numbers develop Covid-19 antibodies via vaccination, it is hoped the rate of decline will accelerate further and across all age groups.
Professor Tim Spector, epidemiologist at King's College London, said vaccines 'should prevent future large-scale outbreaks' and ensure any sudden surges were 'smaller' and 'manageable'.
What's the risk of catching Covid in a pub garden?
Low, but it is still important to be cautious.
A study published last week found that outdoor transmission accounted for just 0.1 per cent of all Covid cases in Ireland.
So, of the 232,164 Covid infections seen in Ireland since the beginning of the pandemic, only 262 were caught outdoors.
Scientists have for some time believed the risk of catching Covid outdoors to be low, due to the fact that even a small wind can disperse Covid particles, making it near-impossible for them to travel from one person's mouth to another's.
Paul Hunter, professor of medicine at the University of East Anglia, said: 'Personally I do not worry about the risk of Covid outdoors and I don't wear a mask outdoors unless I am in a particularly crowded place.'
In June last year, Ian told his GP he wanted to come off zopiclone.
He says: 'He suggested I try one day on, one day off. But when I didn't take the zopiclone I just lay in bed in a sort of twilight, not really sleeping at all.
'I was completely exhausted the next day and unable to function. After a few attempts, I couldn't handle it any more and started taking them every night again.'
Next, again on his GP's advice, he began reducing his dose by splitting his tablets.
He adds: 'I managed to get down to half a tablet, although on that dose I sleep for about five hours a night rather than the seven I had been getting.
'If my dose goes any lower, I can't sleep at all. So I've been stuck. In fact, recently, I've actually had to start increasing what I take. The lockdown hasn't helped, as not being able to see friends has left me more anxious than usual.
'At one point I felt so desperate and agitated I called the Samaritans, and speaking to them helped calm me down. Now I don't know what to do.'
Another patient unable to quit zopiclone is Diana Grieves, 45, a marketing consultant from Hertfordshire. She was initially prescribed the drug eight years ago alongside antidepressants after her mother died in a car accident.
She says: 'Even though I wasn't sleeping, I was hesitant about taking it as my mum had been hooked on temazepam, which is a bit like Valium, for as long as I can remember. But the GP told me, 'Don't worry, these aren't nearly as addictive.'
'They really helped at first. I was out like a light, every night. There were no side effects, either. After nine months or so I decided I felt strong enough to come off the zopiclone. My GP told me to gradually cut down over two weeks, which I did, shaving a bit off my pill each night.
'After a week I'd got down to less than half. But then I suddenly stopped sleeping. I felt like I did after Mum had died – exhausted, unable to cope or concentrate. I was getting angry for no reason.
'I had some zopiclone tablets left and took one. I slept well, and all the symptoms stopped.'
Diana says she has taken the tablets ever since, as the same pattern repeats every time she tries to stop. She admits: 'I want to quit them but I'm scared to even try.'
So what is it about zopiclone that makes it so difficult to give up?
The answer is not simple. Like most sleeping pills, zopiclone and other Z drugs slow down the nervous system to induce sleep.
Patients often report that when they stop taking the tablets, they find it harder than ever to sleep – so-called rebound insomnia.
Some have theorised that the brain becomes dependent on the drug and can't function normally when it is withdrawn.
But studies into this, which involved giving patients either a real pill or a dummy placebo, without them knowing which they were getting, have thrown up intriguing results.
Most reveal that rebound insomnia is seen just as commonly, if not more so, in patients given a placebo, which contains no active drug at all. This suggests that other factors might be leading to the dependence seen in so many patients.
King's College London's Professor Dinesh Bhugra, a former president of the Royal College of Psychiatrists, says: 'Zopiclone is short-acting – it stays in the body for only about six hours, which means it shouldn't cause addiction. But we know people do find it difficult to come off it.
'Like all sleeping pills, zopiclone helps patients sleep, but it doesn't treat whatever is causing that insomnia. And if that underlying cause isn't tackled, it will still be there when the pills are stopped.'
The reasons people suffer severe, long-term insomnia are varied. Mental health problems such as anxiety and depression can 'play havoc' with sleep patterns, says Prof Bhugra.
But, he adds, doctors may need to look further to find the triggers.
'Many patients have money or housing worries or feel trapped in a job or relationship that is causing them unhappiness, so it's no surprise they're stressed, anxious and find it hard to sleep.
'A pill might help treat some of the symptoms, but they won't solve these problems. If doctors are committed to helping these patients, they need to think about their whole life. The focus needs to shift on what we can offer to help them stay well.'
In recent years there has been an NHS drive to promote social prescribing – also known as community referral. GPs are able to refer patients to local exercise classes or gyms, volunteering organisations and even gardening clubs.
Studies have shown these approaches can have a positive impacts on patient wellbeing – reducing stress and their need for medication and other health services.
Dr Mark Horowitz, from University College London, who has studied Z drug dependence, said: 'Insomnia is often a response to stress or grief, and sleep problems improve when the stress lessens or improves.'
With concerns growing about addiction to other prescription tablets, such as antidepressants and anxiety drugs, Prof Moncrieff and Dr Horowitz both hope that further training will be given to GPs and nurses in supporting 'deprescribing' – offering patients support and advice in safely coming off medications.
Current NHS guidance stresses that patients dependent on Z drugs should not be pressured into stopping, and should be allowed to set the timescale for cutting down themselves.
For the time being Ian Govendir and Diana Grieves, like many thousands of others, are in limbo – not wanting to be on zopiclone but not able to stop. Ian says: 'I wish I'd never started taking these pills in the first place.'