Sleep. 2025 Oct 10:zsaf322. doi: 10.1093/sleep/zsaf322. Online ahead of print.
ABSTRACT
STUDY OBJECTIVES: Depression frequently occurs after diagnosis of breast cancer diagnosis. This study examines the incidence of depression, and whether insomnia exaggerates depression risk in long term breast cancer survivors.
METHODS: A sample of 636 non-depressed females, aged 55 to 85 years, was recruited between 2015 and 2020 from a diverse community-based health plan; 315 were breast cancer survivors at least 2 years post-diagnosis, and 321 were an aged-matched comparison cohort. Both groups were stratified by the presence or absence of insomnia at baseline. The primary outcome, incident and recurrent major depressive disorder, was diagnosed over 32 months. Cox proportional hazards models estimated risk of depression [hazard ratio (HR), 95% confidence interval (CI)].
RESULTS: A total of 310 (98.4%) breast cancer survivors, and 309 (96.3%) comparisons completed 32 months follow-up. Relative to the comparisons, risk of depression was elevated in breast cancer survivors (HR = 5.94; 95% CI, 3.34 – 10.54, p<.001). Insomnia, as defined by the Insomnia Severity Index (>8), further increased depression risk breast cancer survivors (HR = 9.91; 95%CI, 4.92 – 19.96; p<.001), but not in the comparisons.
CONCLUSIONS: Long term breast cancer survivors 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 breast cancer survivors.
PMID:41071122 | DOI:10.1093/sleep/zsaf322
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