Sleep dysfunction is universal in ME/CFS patients, although it can take a very wide range of forms. These include dysania, hypersomnia, hypnagogia, insomnia, light sleep, myoclonus, nightmares, night sweats, phase shifting, somnolence, and unrefreshing sleep.
- In the Holmes criteria, sleep disturbance is an optional criteria for diagnosis, under the section Minor Symptom Criteria.
- 2007, Paradoxical NREMS Distribution in “Pure” Chronic Fatigue Patients: A Comparison with Sleep Apnea-Hypopnea Patients and Healthy Control Subjects
"Abstract - Objective: The chronic fatigue syndrome (CFS) is a debated clinical entity, not presently associated with specific sleep abnormalities. However, higher levels of deep sleep and/or lower levels of light sleep have been reported in several all-night polysomnography studies in CFS patients. This distribution of Non-Rapid Eye Movement Sleep (NREMS) contrasts with what would be expected if sleep was interrupted by microawakenings, such as in sleep apneas or periodic limb movements, where more light sleep and less deep sleep are commonly observed. This “paradoxical” distribution of NREMS could represent a characteristic feature of chronic fatigue and deserved to be investigated. Methods: A retrospective comparison of the NREMS distribution was performed between 28 “pure” Chronic Fatigue Syndrome patients (without primary sleep or psychiatric disorders), 27 Apneic-Hypopneic patients and 27 Healthy Controls. Results: Data showed CFS patients to have a higher stage 4/stage 2 or stage 4/light sleep ratios than the other two conditions. Conclusion: This sleep pattern is closer to what is observed in cases of infections than to what is seen after sleep fragmentation by primary sleep or in psychiatric disorders. Such a particular sleep pattern could provide insights into the pathophysiology of fatigue.
Amitriptyline may be helpful for improving quality of sleep in individuals with CFS.  While originally considered an antidepressant, it is also prescribed at low doses to specifically manage pain and sleep for a number of conditions.
- The 1988 Holmes Definition for CFS
- Olivier Le Bon, Daniel Neu, Filomena Valente & Paul Linkowski. (2007). Health-Related Quality of Life in Chronic Fatigue Syndrome versus Rheumatoid Arthritis as Control Group. Journal of Chronic Fatigue Syndrome, Vol. 14, Iss. 2, pp. 45-59. http://dx.doi.org/10.1300/J092v14n02_05