The people suffering from insomnia disorders complain of difficulty in initiating or maintaining sleep or of not feeling rested after sleeping adequate amount of time. Insomnia is associated with acute and chronic medical problems and may be a significant difficulty in those engaged in shift work and other economic activities that are out of phase with societies' normal circadian rhythm. Insomnia is related to depression, stress, environmental disruption and anxiety and there is evidence that it is on the rise.
Certain conditions are needed for the brain to produce the necessary substances to initiate sleep, and experts are only just beginning to understand the ways in which these can be influenced by factors such as food, drink and light.
Sleep researchers are still trying to tease out all the reasons for insomnia, but one thing they do know is people's sleep-wake patterns change as they age. For teenagers and people in their 20s, the peak time of alertness is right before bedtime; insomniacs at this age often have difficulty falling asleep. Bedtime alertness is reduced as people age, they often fall asleep easily but may have trouble maintaining sleep. One reason is that middle-aged and older people may be more sensitive to things like discomfort and noise. Another reason may be changes in the drive to stay asleep, he says. Throughout the day, people build up a need for sleep. When they snooze for a few hours, they pay off some of the sleep debt, and their drive to stay asleep diminishes.
Insomnia is experienced by virtually everyone in society, at some time or other in their lives. An estimated 35% of Europeans have some degree of insomnia, and 10% suffer acutely.
An estimated 60 million adult Americans may have a severe problem with insomnia: 51 percent had symptoms of insomnia a few nights a week; 29 percent experience insomnia every night or almost every night; 32 percent are awake a lot during the night; 24 percent say they wake up early and can't get back to sleep at least a few times a week; and 24 percent say "thinking about something" causes them to have difficulty sleeping at least a few nights a week.
In Chinese medicine, insomnia usually means that blood or yin or both are deficient and incapable of nourishing the shen stored in the heart. There is therefore a relative excess of yang and the body is unable to settle down. Excess fire can also disturb the shen.