Medical Comorbidity of Sleep Disorders

Dimitris Dikeos; Georgios Georgantopoulos


Curr Opin Psychiatry. 2011;24(4):346-354. 

In This Article

Abstract and Introduction


Purpose of review Recently published literature indicates that sleep disorders present with medical comorbidities quite frequently. The coexistence of a sleep disorder with a medical disorder has a substantial impact for both the patient and the health system.
Recent findings Insomnia and hypersomnia are highly comorbid with medical conditions, such as chronic pain and diabetes, as well as with various cardiovascular, respiratory, gastrointestinal, urinary and neurological disorders. Restless legs syndrome and periodic leg movement syndrome have been associated with iron deficiency, kidney disease, diabetes, and neurological, autoimmune, cardiovascular and respiratory disorders. Rapid eye movement behaviour disorder has been described as an early manifestation of serious central nervous system diseases; thus, close neurological monitoring of patients referring with this complaint is indicated.
Summary Identification and management of any sleep disorder in medical patients is important for optimizing the course and prognosis. Of equal importance is the search for undetected medical disorder in patients presenting with sleep disorders.


Sleep disorders are increasingly met in clinical practice, having major effects on well being, overall health and safety, and causing significant economic burden at both the individual and societal levels.[1] Furthermore, sleep disorders are commonly associated with other major medical problems such as chronic pain, cardiovascular disease, dementias, metabolic disorders, gastrointestinal disorders, and so on. Thus, the approach to the patient with sleep complaints should take into consideration medical history, physical findings and a proper evaluation of the patient's physical health. Conversely, sleep disorder symptoms should be sought during any evaluation of a patient with a medical condition, as co-existence of sleep problems is associated with worse quality of life, course and prognosis of the medical condition, and increased use of health system facilities.[2]

In the International Classification of Sleep Disorders (ICSD-2), eight broad categories of sleep disorders are listed, along with several subcategories under each category, as well as additional sleep-related disorders in its Appendices A and B.[3] Leaving out the category of sleep-related breathing disorders (including obstructive sleep apnoea), which falls in the field of pulmonary medicine, the remaining seven broad categories consist of insomnia; hypersomnia of central origin not due to a circadian rhythm sleep disorder; circadian rhythm sleep disorders; parasomnias; sleep-related movement disorders; isolated symptoms, apparently normal variants, and unresolved issues; and other sleep disorders. All of these disorders and those in their subcategories might be comorbid with a multitude of medical conditions, the presentation of which cannot be accomplished within the limited space of one paper. The aim of the present review is to present and discuss the most important of these comorbidities; thus, the scope of the paper will focus on medical comorbidities of insomnia, sleep-related limb movements, that is, restless legs syndrome (RLS) and periodic leg movement syndrome (PLMS), rapid eye movement (REM) sleep behaviour disorder (RBD), and hypersomnias/excessive daytime sleepiness (EDS).


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