How do you know if you have a sleep disorder that even doctors don’t know about?

Do you have trouble getting out of bed without an alarm clock and do you feel tired all day?

You might assume that this familiar-sounding scenario is caused by poor sleep, but for some people it could be a sign of idiopathic hypersomnia (IH), a condition that makes them feel exhausted even when they sleep well.

Sarah Morgan, 41, an administrative assistant from England, first noticed constant daytime exhaustion during her final exams. “I thought I was just stressed,” she recalls. Even after a good night’s sleep, “it was almost impossible to keep my eyes open.”

In fact, this was a hallmark of IH. Those affected may still need a daytime nap after sleeping more than ten hours a night. Severe cases may sleep up to 18 hours a day.

Other signs include brain fog, difficulty waking from sleep, headaches, confusion and losing belongings – as the excessive fatigue means people experience seconds-long ‘micro-sleeps’ in which they carry out activities without being aware of what they are doing.

“IH is underrecognized and often disabling,” says Dr. Paul Reading, a British neurologist and expert on hypersomnia, or excessive sleepiness. ‘It interferes enormously with all aspects of life: social, educational and careers.’

One problem is that IH is easily confused with other conditions, including depression. It means that those affected are given drugs that they do not need, that cause side effects, or that their problems are dismissed as ‘laziness’.

Despite her intense sleepiness, Sarah passed her first exams, but ‘failed’ her follow-up exams because she was always exhausted.

“I went home in the middle of the day because I couldn’t resist the desperate need to take a nap and sleep deeply — even though I had slept well the night before.”

After repeated visits to the GP, who carried out blood tests for conditions that could cause fatigue, such as anemia, Sarah was told she was ‘just young and tired’ and should ‘keep going’.

Excessive daytime sleepiness is generally a common symptom and may be related to inadequate sleep quality or quantity, says Dr Alanna Hare, a consultant at the Royal Brompton and Harefield Hospitals in London who specializes in sleep and breathing.

There are many causes, ranging from obstructive sleep apnea (when breathing stops repeatedly during the night) to a neurological condition such as narcolepsy, medications or psychiatric disorders, Dr. Hare adds.

IH was first discovered in the 1970s and is estimated to affect one in 25,000 adults, although Dr Reading believes the real figure is one in 5,000. ‘It is slightly more common in women, with a peak incidence in the teenage years, although it is often undiagnosed for years.’

The condition is only diagnosed when other possibilities have been ruled out. (Idiopathic means: no known cause.)

“We really don’t know what’s behind it,” says Dr. Reading. ‘Brain scans looking at the major sleep centers, such as the hypothalamus, are normal.’

However, there are distinguishing features. ‘IH is best described as a syndrome of excessive sleep need, in which subjects have excellent sleep, often achieving 9-11 hours of good quality sleep, but still require naps during the day, usually unplanned,’ he explains. Another sign is microsleeps, which is a period of about three seconds ‘when a person appears awake, but is not fully awake’.

‘Losing things in the house or putting house keys in the refrigerator can be a sign of such mistakes.’

These interruptions will sound familiar to anyone who has been sleep deprived, but the key with IH is that these micro-sleeps happen even after a full night’s sleep.

‘The sleepiness in IH also differs from the ‘fatigue’ that people get after doing a demanding mental or physical activity – for example, patients with chronic fatigue syndrome generally do not fall asleep when they are inactive or resting, while patients with IH do that,” he says. .

Dr. Reading adds: ‘Patients often rely on a number of alarm clocks, reporting severe ‘sleep inertia’ or ‘sleep drunkenness’ in the morning and feeling like ‘zombies’ for an hour or so. This is often the worst symptom and the most difficult to treat.’

And unlike someone who is simply ‘not a morning person’, who will generally feel more alert as the day progresses, someone with IH will remain tired throughout the day.

This daytime fatigue can make it difficult to hold down a job, as Sarah discovered in her 20s.

“I wanted to work, but I couldn’t because I could never stay awake long enough during office hours,” she says. ‘It was the frustration of not being able to work on my uni assignments that made me realize I had a serious problem and that it couldn’t just be my attitude – which was a common reaction from most people around me.’

Becoming concerned that something was seriously wrong, she consulted another doctor at the age of 21.

“I didn’t go out or date because I was always tired and avoided friends because no one understood why I was so exhausted.”

She was eventually referred to a sleep clinic in 2004, where she visited Dr Reading, who diagnosed IH.

Although diagnosis largely relies on a patient’s description of symptoms, nightly testing in a sleep lab can help: It shows whether someone is getting good quality sleep and can rule out conditions such as sleep apnea. It is also assessed how quickly a patient falls asleep.

“Most patients with IH need an average of seven minutes or less to lose weight,” says Dr. Reading. (Ten minutes or more is considered normal). Overnight testing can also reveal other features of IH, including “excessive slow wave (deep) sleep that lasts late into the night,” Dr. Reading explains. ‘For most people, the deepest stages of sleep occur in the first two hours after falling asleep, but in IH, deep sleep can continue or return late at night and hinder easy awakening.’

Dr. Hare adds: ‘Because we don’t yet fully understand the underlying disease process and we don’t have biomarkers, it is very difficult to make a firm diagnosis.’

This also means that treatment for IH is only for the symptoms.

In addition to psychostimulants (amphetamine-like drugs), there are newer medications such as modafinil (used to treat ADHD) and Wakix (developed for narcolepsy). ‘These newer drugs work specifically on the ‘waking mechanism’ part of the brain and have fewer side effects – for example in the heart – than amphetamines,’ says Dr Reading, which he says is no longer the first-line treatment but can be prescribed as a back -upoption.

“Most patients improve with medications, but it is relatively rare to achieve ‘normality,'” he adds.

Sarah was not bothered by the prescribed amphetamines: ‘I was nervous, talking so fast that people couldn’t keep up. It kept me awake, but changed my personality. I felt like I was always rushing through life.’

She took them for six years and also tried Wakix; however, she stopped because of the side effects – extreme headaches, visual problems and rapid heart rate – and because she started trying to start a family.

She had her first child in 2014 and became the mother of three children. ‘Being a mother of young children when all you want to do is sleep was terrible. I honestly don’t know how I stayed awake.’

She says she also felt very lonely as some family members and friends doubted her diagnosis and told her to “just stop it – luckily my partner was a real support.”

Lack of understanding about the condition contributes to severe frustration, “which can develop into serious mood disorders such as anxiety,” says Dr. Reading. ‘It is then assumed that the resulting sad mood or anxiety causes the excessive sleepiness – but there is no evidence that depression causes true hypersomnolence (excessive sleepiness); it’s almost always the other way around!’

In addition, the medications used to treat mood disorders can affect the sleep-wake cycle and worsen the inability to wake up in the morning or work a conventional shift pattern, says Dr. Reading.

Aside from the right medication, a sleep specialist may be able to advise on lifestyle changes that can help: from timing meals to sticking to them where possible, to regular sleep and wake times. The good news is that “in my experience, IH improves as people get older,” says Dr. Reading.

Meanwhile, Sarah is doing her best without medication. She manages to work part-time, but still struggles.

“No matter how much sleep I get at night, I’m exhausted by mid-morning,” she says. She has started a Facebook support group for other patients.

She adds, “One of the hardest things is that when you explain it to people, they still don’t believe you.”