Depression and insomnia in cancer: prevalence, risk factors, and effects on cancer outcomes.

Over two-thirds of the 11.4 million cancer survivors in the United States can expect long-term survival, with many others living with cancer as a chronic disease controlled by ongoing therapy. Behavioral comorbidities often arise during treatment and persist long term to complicate survival and reduce quality of life. This review focuses on depression and insomnia with an emphasis on understanding the role of cancer-specific factors and their contribution to the prevalence of these behavioral comorbidities in cancer patients following cancer diagnosis and treatment. The clinical significance of depression and insomnia for cancer patients is further stressed by epidemiological observations that link depression and insomnia to cancer morbidity and mortality risk.