Chronic fatigue: Symptom and syndrome

Chronic fatigue is common, is difficult to measure, can be associated with considerable morbidity, and is rarely a subject of controversy. The chronic fatigue syndrome also presents problems in definition and measurement, is associated with even more morbidity than chronic fatigue itself, and is oft en controversial. Particularly unclear is the way in which chronic fatigue and the chronic fatigue syndrome relate to each other: Is one the severe fo rm of the other, or are they qualitatively and quantitatively different? We know that many things can cause chronic fatigue, and this is probably true for the chronic fatigue syndrome, too. We can anticipate that discrete cau ses of the chronic fatigue syndrome will be found in the future, even if th ese causes are unlikely to fall neatly along the physical-psychological div ide that some expect. The causes of chronic fatigue are undoubtedly many, b oth in a population and in any individual person, even when a discrete caus e, such as depression or cancer, is identified. Social, behavioral, and psy chological variables are important in both chronic fatigue and the chronic fatigue syndrome. Interventions that address these general variables can be successful, and currently they are often more successful than intervention s directed at specific causes.