Insomnia is a widespread problem affecting between - 15% and 30% of the adult population. Half of the people complaining of insomnia consider their problem serious enough to seek professional help. Insomnia is perhaps the second most prevalent health complaint after pain. It is twice as frequent in women as in men and its incidence increases with age.

Insomnia is not a trivial complaint. Chronic sleep disturbances may have a detrimental impact on daytime functioning. It can cause considerable distress and impair the quality of life. It can also lead to mood problems, fatigue, and performance impairment (memory, alertness, concentration), which in turn can jeopardize jobs and relationships.