Chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is characterized by disabling fatigue that significantly interferes with people's ability to carry out their normal daily activities. This article describes the core symptoms and details diagnostic criteria, in addition to discussing aetiology, risk factors, onset, prognosis and prevalence. Many patients diagnosed with CFS also meet the criteria for common psychiatric disorders, particularly depression. Issues regarding co-morbidity and the relationship between CFS and psychiatric illness are discussed. We outline two popular approaches to understanding CFS; the cognitive behavioural and deconditioning paradigms. The cognitive behavioural model attempts to explain how life stresses can precipitate CFS in predisposed persons, and how cognitive, physiological, behavioural and social factors then interact to perpetuate the illness creating a vicious cycle of chronic fatigue and disability. Deconditioning, a physiological process leading to a decrease in the body's efficiency, reduces the body's capacity for physical exertion, leading to an increase in fatigue symptoms at lower levels of exercise than previously. Treatments for CFS are discussed, with the focus being on two non-pharmacological interventions; cognitive behavioural therapy (CBT) and graded exercise therapy (GET), which have been shown to be very effective in treating CFS. Finally, we discuss CFS in children and adolescents which in recent years, has become more acknowledged. Prevalence and treatment of CFS in children is discussed with special attention being paid to developmental issues.