Insomnia is a disorder in which people have trouble getting to sleep or staying asleep long enough to feel refreshed the following day. Specifically, sufferers may take a long time to fall asleep, find themselves waking up frequently or for long periods of time in the middle of the night, wake up too early in the morning and be unable to get back to sleep, or feel tired and irritable during the day.
Insomnia is a reasonably common problem, affecting 1 in 3 people, and can either occur as occasional episodes or as a recurring issue. The condition is often found in people who are anxious, experiencing a great deal of stress, have a mental or physical health condition (like depression or long-term pain) or are taking certain medications. It can also occur as a result of lifestyle factors like jet lag, over consumption of caffeine or shift work.