What is hypersomnia?
A drug normally used to revive patients who have overdosed on sedatives was found to reverse the effects of sleep-inducing brain chemicals.
Mon, Nov 26, 2012 at 11:15 AM
A new treatment may help people with a bizarre medical condition that makes them perpetually sleepy.
The findings, detailed Nov. 21 in the journal Science Translational Medicine, may provide relief for the people who sleep constantly and feel exhausted despite caffeine, other stimulants, and several alarm clocks.
People with hypersomnia need to sleep about 70 hours a week and have trouble rousing from sleep. When they are awake, they usually feel as if they've pulled an all-nighter, and describe it as walking around in a fog. Most people come to a diagnosis after conditions like depression, sleep apnea or thyroid problems have been ruled out, said study co-author David Rye, a sleep researcher at Emory University.
"You look for the typical causes, and then once you rule all those out, you're left with people who still sleep 12, 13, 14, 15 hours," Rye told LiveScience.
For obvious reasons, intense sleepiness can put a crimp in patients' work and social lives. While no one knows exactly how many people have this condition, Rye estimates that roughly 1 in 800 people might be afflicted. Doctors often prescribe patients stimulants such as Ritalin or Adderall, but they don't usually work. [5 Things You Didn't Know About Sleep]
So Rye's team wondered whether brain chemicals could cause hypersomnia. Because spinal fluid provides a snapshot of the chemicals floating around the brain, the team took spinal taps from 32 patients with the disease and 16 healthy subjects.
When they put the spinal fluid in a dish with human cells, nothing happened.
So the researchers added a chemical called gamma-aminobutyric acid (GABA), which helps the body shut down. The spinal fluid of the ultra-sleepy amplified the effects of GABA, making it bind much more often to the human cells. (Past research showed a link between GABA and sleep paralysis, or the phenomenon in which one wakes up while his or her muscles are still frozen.)
The sleepy patients were producing a brain chemical that kept them half-sedated all of the time, Rye said.
In a petri dish, adding a drug called flumenazil, which revives patients who have overdosed on sedatives such as Valium, reversed the effects of the sleepy peoples' spinal fluid.
They then tested flumenazil in the sleepy patients. Before taking the drug, hypersomniacs performed as well as the extremely sleep-deprived or slightly inebriated on a test of alertness.
"They're walking around essentially legally drunk all day," he said.
Afterwards, the sleepy cohort performed almost as well as healthy individuals.
The findings suggest that the drug could be an effective treatment for those with hypersomnia, but a follow-up study needs to prove that they actually sleep less at night, he said.
Currently, the drug is only used to treat drug overdoses or to awaken patients unconscious from anesthesia, so the amount of the drug currently produced could only treat a handful of patients. Production would need to increase before it could be widely used, he said.
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