Insomnia and elevated risk of major depressive disorder in older adult, long-term breast cancer survivors vs a matched cohort

Long-term BCSs have a heightened risk of major depressive disorder, and even subthreshold insomnia exaggerates that risk. Given that insomnia treatment can effectively prevent depression, insomnia screening and treatment have implications for depression prevention in BCSs. Statement of Significance Breast cancer survivors with insomnia show a markedly elevated risk of depression, which supports the urgent need to screen for insomnia in cancer survivors and to develop and implement insomnia treatment to prevent depression in this high-risk population.