Depression and Severe Mental Disorders. The Centers for Disease Control (CDC), which established the definitions for chronic fatigue syndrome, recognizes depression as one of the symptoms of CFS. In one study, 36% of CFS patients were depressed. Depression in these patients was associated with lower self-esteem and an increased likelihood of suicidal thoughts. However, according to the CDC, anyone with major depression or other severe psychiatric disorders, including bipolar disorder and schizophrenia, does not meet the criteria for chronic fatigue syndrome.
Symptoms of major depression include the following:
- A depressed mood every day
- Significant weight gain or loss (10% or more of an individual's usual body weight)
- Insomnia or excessive sleeping
- Restlessness or a sense of being slowed down
- Low energy every day
- Worthless or inappropriately guilty feelings
- An inability to concentrate or make decisions
- Suicidal thoughts
- Loss of interest and enjoyment
Major depression is likely if a person has several of these symptoms and no physical symptoms (such as sore throat, aches and pains, or fever). The longer fatigue has continued without physical symptoms, the more likely that the diagnosis is depression.
A persistent form of minor depression called dysthymia may be more difficult to differentiate from CFS and may actually account for a subset of CFS cases. Dysthymia has many of the same symptoms as major depression, but these symptoms are less intense and last much longer -- at least 2 years. The symptoms of dysthymia have been described as a "veil of sadness" that covers most activities.
Patients with depression generally perceive their illnesses differently than people with CFS:
- Patients with depression have significantly lower self-esteem, more thought distortions (for instance, focusing on the negative or personalizing their situations), and believe their condition stemmed from psychological factors.
- CFS patients, even those who also have depression or dysthymia, tend to identify medical causes as the source of their problems and to focus on physical symptoms.
Many previously healthy patients with CFS become depressed and anxious because they feel so exhausted all the time. CFS may also lead to highly stressful socioeconomic situations, such as social isolation and poverty. These situations can contribute to, and even cause emotional disorders in susceptible individuals, which can worsen CFS.
Sleep Disturbances. Certain sleep disorders may cause persistent fatigue and can be confused with CFS:
Review Date: 01/10/2011
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.