Skip to Main Content


Chronic fatigue syndrome is not tiredness: there is a difference between feeling tired and ‘fatiguey’. Fatigue involves a heaviness in the limbs, a sense of inability to think or move, pain in muscles and joints, nausea etc. Please understand the difference.

CFS patient to author, January 1995

Tiredness, which basically means ‘a desire to rest’, or chronic fatigue is not a diagnosis but rather a symptom of illness: it may occur as either a presenting or a supporting symptom. Tiredness is interchangeable with terms such as weariness, lethargy, loss of energy, listlessness and exhaustion. It is a common and difficult presenting symptom often known by the acronym TATT—‘tired all the time’. The symptom of tiredness is likely to be ‘hidden’ behind the request for a tonic or a physical check-up.1

Tiredness can be a symptom of a great variety of serious and uncommon diseases, including malignant disease. The challenge for the family doctor is to diagnose such disorders quickly without extravagant investigation.

Key facts and checkpoints

  • The commonest cause of tiredness is psychological distress, including anxiety states, depression and somatisation disorder.

  • An Australian study showed that fatigue presents at a rate of 1.4 per 100 encounters.2

  • The study by Hickie et al3 showed that 25% of a sample of attendees visiting general practices had chronic fatigue. Of these, 70% had psychological distress. The others were more likely to have a current depressive disorder.

  • In Jerrett's study4 no organic cause was found in 62.3% of patients presenting with lethargy; the constant factors were sleep disturbance and the presence of stress in their lives. Many of them turned out to be suffering from psychological problems or psychiatric illnesses, including depression, anxiety state or bereavement.

  • An important cause of daytime tiredness is a sleep disorder such as obstructive sleep apnoea, which results in periodic hypoventilation during sleep. It occurs in 2% of the general population in all age groups and in about 10% of middle-aged men.4 A history of snoring is a pointer to the problem. See CHAPTER 71.

  • Underlying disorders that need to be considered as possible causes of chronic fatigue are endocrine and metabolic disorders, malignancy, chronic infection, autoimmune disorders, primary psychiatric disorders, neuromuscular disorders, anaemia, drugs and cardiovascular disorders.

  • Prolonged or chronic tiredness is characterised clinically by disabling tiredness, typically lasting more than 2 weeks, associated with non-restorative sleep, headaches and a range of other musculoskeletal and neuropsychiatric symptoms.3

  • Sociodemographic correlates are concurrent psychological distress, female sex, lower socioeconomic status and fewer total years of education.3

  • Chronic fatigue syndrome (CFS) is defined as debilitating fatigue, persisting or relapsing over 6 months, associated with a significant reduction in activity levels of at least 50%, and for which no other cause can be found.

Causes of tiredness

Analysing the symptom and reaching a diagnosis demands considerable skill, since ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.