Table 1.
Diagnostic criteria for chronic fatigue syndrome (see text).
| CDC 1994 | Oxford, UK |
| Clinically evaluated, medically unexplained fatigue of at least 6 months’ duration that is: | Severe, disabling fatigue of at least 6 months’ duration that: |
| – of new onset | – affects both physical and mental functioning |
| – not a result of ongoing exertion | – was present for more than 50% of the time |
| – not substantially alleviated by rest | |
| – a substantial reduction in previous levels of activity | |
| The occurrence of 4 or more of the following symptoms: | Other symptoms, particularly myalgia, sleep and mood disturbance, may be present |
| – subjective memory impairment | |
| – tender lymph nodes | |
| – muscle pain | |
| – joint pain | |
| – headache | |
| – unrefreshing sleep | |
| – postexertional malaise (greater than 24 hours) | |
| Exclusion criteria | |
| – active, unresolved, or suspected disease likely to cause fatigue | – active, unresolved, or suspected disease likely to cause fatigue |
| – psychotic, melancholic, or bipolar depression (but not uncomplicated major depression) | – psychotic, melancholic, or bipolar depression (but not uncomplicated major depression) |
| – psychotic disorders | – psychotic disorders |
| – dementia | – dementia |
| – anorexia or bulimia nervosa | – anorexia or bulimia nervosa |
| – alcohol or other substance misuse | |
| – severe obesity | |
CDC, US Centers for Disease Control and Prevention.