Medical Comorbidity of Sleep Disorders

Dimitris Dikeos; Georgios Georgantopoulos


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

In This Article


The sleep disorders whose comorbidities are reviewed in the present paper are insomnia, the sleep-related limb movements RLS and PLMS, RBD and hypersomnia. Medical comorbidities are quite frequent among all these conditions. Sleep disorders may be either the result of the discomfort caused by a medical condition, a symptom caused by mechanisms related to the medical condition (such as the dopaminergic dysregulation of neurodegenerative disorders, which may be the causative factor of RBD, or the production of cytokines in rheumatologic disorders, which may cause a variety of sleep problems), a contributing factor to it, or even a separate nosological entity.

Of all these sleep disorders, insomnia and hypersomnia have the highest number of comorbid medical conditions, followed by RLS/PLMS and RBD. The impact of the coexistence of sleep problems with a medical disorder is substantial: presence of any sleep disorder has an impact on the quality of life of the patients, the use of health system resources by them, their overall health outcome, the loss of productivity and the probability of their involvement in domestic, industrial or traffic accidents. In addition, recognizing certain sleep disorders such as RLS/PLMS not only reduces suffering and the above-mentioned potential consequences, but it may also reveal conditions (such as normal haemoglobin iron deficiency) that might otherwise go undetected. Although RBD presents with fewer comorbid medical conditions compared with the rest of the sleep disorders, it seems to be a disorder that in many cases is the earliest manifestation of a serious neurological disease, and the detection of its presence must alert the attending physician to closely monitor the patient for a number of years. In the meantime, therapeutic interventions should target the symptoms of RBD and preventive measures taken for the protection of the patient and his/her partner from possible accidents during sleep. Finally, hypersomnia, apart from the high risk of accidents that it is associated with, is also a condition that has been associated with higher general morbidity and mortality, and its presence should be taken as a sign to follow patients more carefully and treat them more intensively.

In conclusion, recognition and management of sleep disorders in any medical patient is quite important; furthermore, the search for undetected medical conditions in patients presenting with sleep disorders might also reveal an underlying medical disorder that has not yet been manifested.


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