Most of us have suffered from a few nights of bad sleep, making it difficult to stay awake during the day. But for a select group of people, extreme daytime sleepiness cannot be remedied by getting more shut-eye. This group has what’s called primary hypersomnia. It’s a rare condition in which patients are continuously tired, despite sleeping, on average, nearly 11 hours a day, or up to 75 hours per week.
Until now, the cause of hypersomnia was not known, but researchers at Emory University think they’ve found a lead. They’ve identified a mysterious chemical that acts like a sedative in the brains of people who can’t seem to stay awake.
In the human brain, a chemical called gamma-amino butyric acid, or GABA, works to calm us down when it binds to its receptor. But in individuals with primary hypersomia, researchers believe this mystery substance in the cerebrospinal fluid (a clear fluid that “bathes” the brain and spinal cord) binds to the receptor and “changes its biophysical properties so that it becomes more sensitive to GABA when it sees GABA,” lead author David Rye, a professor of neurology at Emory University School of Medicine, explained to us in an email.
This, in turn, enhances the effects of GABA, the brains natural “shut down” neurtransmitter.
People who suffer from hypersominsia say they “take a coma,” rather than a nap, Rye tells us. That’s because naps are generally refreshing. These people take long, deep nighttime and daytime sleeps that are not refreshing.
“They typically resort to elaborate means to get themselves to wake-up — for example, multiple alarm clocks — some that fly, some that walk and that need to be physically ‘caught’ in order to turn them off,” Rye wrote.
For the study, researchers gave seven hyper-sleepy patients a drug called flumazenil, which is typically used to treat people who overdose on sleep-inducing medications like Valium or Ambien. The treatment improved reaction times and alertness in some patients. This suggested there was some kind of substance mimicking the effects of sleeping pills in hypersomnia patients, though researchers are still not sure what that substance is.
According to a press release from Emory University, “based on its size and sensitivity to certain enzymes, it could be a peptide.”
Currently, there are no approved treatments for hypersomnia. Doctors typically prescribe stimulant medications like Adderall, but there is little data to support their use, Rye said.
The new knowledge will help doctors find more effective treatments for a disorder that could affect at least 1 in 800 Americans, but is not well studied.
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