INSOMNIA
Insomnia is a sleeping disorder characterized by persistent
difficulty falling asleep or staying asleep despite the opportunity. It is
typically followed by functional impairment while awake. Insomniacs have been
known to complain about being unable to close their eyes or "rest their
mind" for more than a few minutes at a time. Both organic and non-organic
insomnia constitute a sleep disorder.According to the U.S. Department of Health
and Human Services, approximately 60 million Americans suffer from insomnia
each year. Insomnia tends to increase with age and affects about 40 percent
of women and 30 percent of men.
A common misperception is that the amount of sleep a person requires decreases as he or she ages. The ability to sleep for long periods, rather than the need for sleep, appears to be lost as people get older. Some elderly insomniacs toss and turn in bed and occasionally fall off the bed at night, diminishing the amount of sleep they receive.An overactive mind or physical pain may also be causes. Finding the underlying cause of insomnia is usually necessary to cure it. Insomnia can be common after the loss of a loved one, even years or decades after the death, if they have not gone through the grieving process.(1)
source
: wikipedia