The term “insomnia” refers to a clinical condition in which various kinds of sleep disorders are observed, which leads to increased fatigue, fatigue and irritability during the waking period. The disease can become a favorable ground for the development of other pathological conditions, for example, depression or hypertension. Depending on the leading symptom, insomnia is usually divided into several subtypes. Questions of the etiology and pathophysiology of the disease include a variety of combinations of genetic, environmental, physiological and behavioral factors. In the treatment of insomnia, it is worth giving preference to behavioral methods, the use of medications is indicated in some cases, provided that rational dosages with a limited duration are used. Since the disease is quite common, a huge number of studies are currently being conducted aimed at studying the pathological condition and creating new treatment tactics, while giving preference to the non-drug option. The article discusses various aspects of the etiology and pathophysiology of insomnia, as well as the role of gender and age on the characteristics of this pathological condition.