Insomnia is the perception or complaint of inadequate or poor-quality sleep because of one or more of the following: 1) difficulty falling asleep 2) waking up frequently during the night with difficulty returning to sleep 3) waking up too early in the morning unrefreshing sleep Insomnia is not defined by the number of hours of sleep a person gets or how long it takes to fall asleep. Individuals vary normally in their need for, and their satisfaction with, sleep. Insomnia may cause prob...