Cognitive and mood disturbance as causes and symptoms of fatigue in cancerpatients

Fatigue, cognitive dysfunction, and depression are very common in cancer pa tients. A relationship among the three entities is recognized but poorly un derstood. Factors that contribute to this poor understanding are the subjec tive nature of the symptoms, multiple potential causes, and a lack of relia ble assessment tools. An understanding of fatigue in cancer patients may be nefit from studies of chronic fatigue syndrome (CFS) and other nonmalignant diseases indicating that cognitive impairment varies with physical and men tal fatigue, and that symptoms of depression experienced by patients with p hysical illnesses and primary mood disorders are qualitatively different. T he multidimensional nature of fatigue suggests that interventions should be patient-specific. They could be related to lifestyle or involve the use of specific behavioral or pharmacologic therapies. As is the case with depres sion and cognitive disorders, targeted interventions against cancer-related fatigue will benefit from a better understanding of its potential biologic causes. Consideration of cognitive dysfunction and depression complicates the understanding of cancer-related fatigue; however, it provides opportuni ties to assist patients who must deal with this serious problem. (C) 2001 A merican Cancer Society.