According to an article published in the Journal of Clinical Sleep Medicine, insomnia is characterized by difficulties initiating, sustaining, or obtaining qualitatively satisfying sleep despite adequate sleep opportunities and circumstances, resulting in impaired daytime functioning.
Insomnia can occur across the majority of the human lifespan, from childhood years to old age.
Over 33% of adults experience insomnia at least intermittently, whereas 10% to 22% suffer chronic sleep difficulties.
Edinger JD, Buysse DJ, Deriy L, et al.
Quality measures for the care of patients with insomnia.
J Clin Sleep Med.