Depression as expressed in patients with ME/CFS is generally considered as secondary depression or reactive depression due to the debilitating effects of ME/CFS. Secondary or reactive depression is common in many chronic illnesses as well as cancer, which may be an acute or chronic illness.
ME/CFS is often misdiagnosed as depression, as many symptoms can overlap. Older case definitions, such as the Fukuda criteria and the Holmes criteria do not differentiate enough between the symptomatic criteria of depression and CFS. In 2006, Hawk, Jason, and Torres-Harding found that symptom occurrence variables as identified in the Fukuda criteria only correctly classified 84.4% of cases when comparing patients with major depressive disorder and ME/CFS.
Hawk, Jason, and Torres-Harding defined several symptoms in which ME/CFS patients experience differently than major depressive disorder patients. When the researchers used the percentage of time fatigue was reported, post-exertional malaise severity, unrefreshing sleep severity, confusion–disorientation severity, shortness of breath severity, and fewer self-reproach items (as scored on the Beck's Depression Inventory), they were able to report 100% correct classification between patients with depressive disorder versus ME/CFS.
- 1) Individuals with major depressive disorder often cannot provide a reason or identify a loss to explain their depressed mood. ME/CFS patients are more likely to report feeling discouraged and depressed because of the inability to perform tasks, be employed, or engage in social functions due to ME/CFS symptoms.
- 2) Depressed patients typically report a lack of interest in activities they previously found pleasurable. ME/CFS patients say they would engage in favorite activities more if their illness would allow it.
- One question that can differentiate the two groups is to ask the patient, "If you were cured tomorrow, what would you do?" Depressed patients typically can not answer the question without forethought. ME/CFS patients typically can list an abundance of activities without prompt. The Forgotten Plague Facebook page had a "If I was cured tomorrow..." campaign encouraging ME/CFS patients to upload their dreams to highlight this difference.
- 3) Although both patients report fatigue, only ME/CFS report post-exertional malaise typically worsening 12 to 48 hours after an activity and lasting for days to weeks.
- 4) In depressed patients, the diminished ability to think or concentrate should improve with antidepressant therapy. In patients with ME/CFS, antidepressants often do not improve concentration or memory.
- Katrina Berne reports a prevalence of 65-90% for depression.
- In the Holmes criteria, depression is an optional criteria for diagnosis, under the section Minor Symptom Criteria - Neuropsychologic Complaints.
- 2016, Chronic Fatigue Syndrome vs. Depression: One Doctor's View: Lack of Energy or Lack of Desire? by Adrienne Dellwo
- 2014, How to Prove to Your Doctor You’ve Got Chronic Fatigue Syndrome (ME/CFS) And Are Not Just Depressed by Cort Johnson
- 2008, Depression or chronic fatigue syndrome? by Michael C. Laferney
- Castro-Marrero, Jesus; Sáez-Francàs, Naia; Santillo, Dafna; Alegre, Jose (2017), "Treatment and management of Chronic Fatigue Syndrome/Myalgic Encephalomyelitis: all roads lead to Rome", British Journal of Pharmacology, doi:10.1111/bph.13702
- DeJean, D.; Giacomini, M.; Vanstone, M.; Brundisini, F. (2013), "Patient experiences of depression and anxiety with chronic disease: a systematic review and qualitative meta-synthesis" (PDF), Ontario Health Technology Assessment Series, 13 (16): 1-33
- Hawk, C; Jason, L; Torres-Harding, S (2006), "Differential diagnosis of chronic fatigue syndrome and major depressive disorder" (PDF), International Journal of Behavioral Medicine, 13 (3): 244-51, PMID 17078775, doi:10.1207/s15327558ijbm1303_8
- Laferney, Michael C. (2008), "Depression or chronic fatigue syndrome?", Current Psychiatry, 7 (1): 91-94
- Berne, Katrina (1 Dec 1995), Running on Empty: The Complete Guide to Chronic Fatigue Syndrome (CFIDS), 2nd ed., Hunter House, p. 60, ISBN 978-0897931915
- The 1988 Holmes Definition for CFS