The aim in this literature review is to describe the definitions, denominations, clinical signs and symptoms, explanations, causative factors and interrelationships of the intensive care syndrome discussed since 1950. It was found that there is no agreement about which symptoms should be included in the syndrome, when the syndrome may appear and how many patients may be affected. Furthermore, it is unclear what causes the development of the syndrome; most authors conclude that there are many reasons for it. The syndrome has generally been examined by using a medical or psychological approach, but during the last few years it has also been described and analysed from a nursing care perspective.