1.   But in July, Czeisler will begin studying melatonin as a sleeping pill for NASA astronauts, who often have severe sleep problems.

2.   But Sampson, who grew up in Lewiston, Maine, and often sought refuge in the great outdoors, had been suffering from a severe sleep disorder.

3.   Despite our sometimes severe sleep deprivation, the running gives us more energy and the camaraderie is invaluable.

4.   Now there is a new compound - modafinil - which can treat the severe sleep disorder narcolepsy.

5.   The troops undergo severe sleep and food deprivation while going through exercises designed to simulate harsh battle conditions.

6.   This sleeping-and-waking cycle can be repeated hundreds of times each night, leading to severe sleep deprivation and daytime drowsiness.

7.   Doctors later said he did not suffer from heart problems, but instead from a severe sleep disorder.

8.   Earlier, Huizenga testified that in the days after the slayings, Simpson suffered tremendous stress and barely could stay awake during the day because of severe sleep deprivation.

9.   The men undergo severe sleep and food deprivation while going through maneuvers to simulate harsh battle conditions.

10.   It has been manufactured by Swiss pharmaceutical giant Hoffmann-LaRoche for two decades as a treatment for severe sleep disorders.