Insomnia is a sleep disorder defined as difficulty initiating or maintaining sleep at least 3 nights per week for at least 3 months and is associated with daytime impairment. The prevalence of insomnia is high, approximately 10% in the general population. Symptoms of insomnia (i.e. sleep difficulties in the absence of a full diagnosis) are even more common, with prevalence higher than 30%. The rate of insomnia symptoms in elderly populations is even higher, with approximately 50% of older adults regularly complaining about significant sleep disturbances.