This sleep disorder could be as common as well-known mental health conditions

Key points:

• ‘Idiopathic hypersomnia’ is a sleep disorder that leads people to feel extremely tired during the day despite uninterrupted sleeping patterns at night

• New research has found that the neurologic disorder may not be as rare as once thought

• Symptoms also include sleeping excessive amounts of time, having difficulty waking up, and waking up disoriented

Although severely detrimental to personal, professional, health and interpersonal well-being, the National Disability Insurance Scheme does not provide funding for all sleep disorders. Despite this, new research has revealed that more people could have a sleep disorder than initially thought.

Idiopathic hypersomnia, which is characterised by feeling consistently fatigued and sleepy despite regular or excessive rest at night, differs from narcolepsy, which is estimated to affect three in every 10,000 Australians.

Similarly, idiopathic hypersomnia was estimated to affect as many as one to two out of every 10,000 people worldwide. New research suggests that the number of people who actually live with or experience the sleep disorder could be more than that estimated prevalence.

A study published in the December 13, 2023, online issue of the medical journal Neurology examined data from a large sleep study and found that the condition could actually be as common as the population rates of people with other common neurologic and psychiatric conditions, such as epilepsy, bipolar disorder and schizophrenia.

“It has been difficult to determine the prevalence of idiopathic hypersomnia because expensive and time-consuming sleep testing is required to make a diagnosis,” David Plante, PhD, of the University of Wisconsin-Madison and the study’s author, said.

“We examined data from a large sleep study and found that this condition is much more common than previous estimates.”

For the study, researchers examined sleep data for 792 people with an average age of 59. All participants completed an overnight sleep study and a daytime nap study, which measures how fast someone falls asleep throughout four or five naps.

Participants were also surveyed about daytime sleepiness, fatigue, the amount of time they spent napping and how many hours of sleep they get on a work night and a non-work night.

Researchers determined that 12 people had probable cases of idiopathic hypersomnia, for a prevalence of 1.5 percent — considerably higher than the ‘three in 10,000’ estimate.

During the sleep studies, people with idiopathic hypersomnia took an average of four minutes to fall asleep at night and six minutes during naps, compared to an average of 13 minutes at night and 12 minutes during naps for people without the disorder.

They found for the 10 people for whom data were available, excessive daytime sleepiness was often chronic.

However, sleepiness went away for four people or 40 percent of those studied.

Dr Plante said that not only does that provide hope for people with the disorder, but it also underscores the need to further study what leads to remission.

“Our results demonstrate that idiopathic hypersomnia is relatively common, more prevalent than generally assumed, so there is likely a sizable difference between the number of people with this disorder and those who seek treatment,” he explained.

“Further efforts to identify, diagnose and treat those impaired by idiopathic hypersomnia are needed. Additional research may also clarify the causes of idiopathic hypersomnia and lead to new treatments.”

More information about the NDIS and sleep disorders can be found through the Disability Support Guide to insomnia, obstructive sleep apnoea, restless legs syndrome, circadian rhythm sleep disorders and hypersomnolence disorders.

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Sleep disorders and the NDIS: What you need to know

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