Fatigue, depression, and insomnia: evidence for a symptom cluster in cancer

OBJECTIVES: To review the evidence for considering fatigue, depression, and insomnia as a symptom cluster in cancer. DATA SOURCES: Empirical studies, clinical articles, and review articles. CONCLUSION: The single- and multi-symptom measurement approaches are of limited usefulness in distinguishing fatigue, depression, and insomnia. Studies in which these symptoms have been measured concurrently in patients with cancer yield consistent evidence of high positive correlations. Results do not appear to be solely a function of overlap in measurement approaches. IMPLICATIONS FOR NURSING PRACTICE: Successful management of fatigue, depression, and insomnia in cancer patients are likely to combine pharmacologic and nonpharmacologic therapies.