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Department of Psychiatry

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Book Chapter


Musculoskeletal, Neural, and Ocular Physiology | Neuroscience and Neurobiology | Physiology | Psychiatry and Psychology | Sleep Medicine


Sleep is a reversible state of disconnection from the environment, including reduced consciousness, skeletal muscle mobility, and metabolism. All forms of sensory responses are markedly decreased to varying degrees depending on the sleep cycle stage. Although this phenomenon is observed in all species that have been studied and occupies a significant fraction of the human lifespan, the purpose and function of sleep remain poorly understood.

Sleep is measured primarily by polysomnography (PSG) which is considered the gold standard for diagnosing sleep disorders.. PSG reveals that sleep architecture has several distinct stages that vacillate between the non-rapid eye movement (NREM) stages and rapid eye movement (REM) stages. The REM stage is of particular interest due to its association with various pathological, psychological, and physiological phenomena. The wide variety of medical and psychiatric pathologies, as well as common pharmacotherapies that can disrupt normal sleep, are summarized in this article. With more than 50 million Americans affected by sleep loss, the treatment of sleep disorders is becoming an increasingly more specialized and interprofessional field with a significant impact on patient health in both acute and chronic settings.


sleep, REM sleep, physiology, testing

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Copyright © 2021, StatPearls Publishing LLC. This book is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits use, duplication, adaptation, distribution, and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, a link is provided to the Creative Commons license, and any changes made are indicated.


Feriante J, Araujo JF. Physiology, REM Sleep. 2021 Feb 23. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan–. PMID: 30285349. Link to book chapter in NCBI Bookshelf

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Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.