Cancer-Related Dysfunctional Beliefs about Sleep May Influence Insomnia of Cancer Patients Regardless of Depressive Symptoms

Background and ObjectiveaaDepression is one of the major causes of insomnia among cancer patients, and should be explored among cancer patients who are suffering from insomnia. The objective of this study was to explore whether dysfunctional beliefs about sleep among cancer patients were associated with insomnia independent of depression. MethodsaaMedical records of patients who visited Asan Medical Center sleep clinic for cancer were reviewed retrospectively from January to November of 2017. The data included the patient’s psychiatric symptoms and assessment of sleep disorders Insomnia Severity Index (ISI), Patient’s Health Questionnaire-9 (PHQ-9), State-Trait Anxiety Inventory (STAI), Fear of Progression (FoP), and Cancer-related Dysfunctional Beliefs about Sleep (C-DBS) and a clinical interview. ResultsaaResults indicated that ISI score was significantly correlated with PHQ-9, FoP, and CDBS scores, and C-DBS score was significantly correlated with ISI, PHQ-9, and FoP scores all, p < 0.01). The ISI and C-DBS scores were not significantly correlated with age and the STAI-State scale. Linear regression analysis revealed that C-DBS (β = 0.40, p < 0.001) and PHQ-9 scores (β = 0.30, p < 0.01) predicted ISI scores among all participants. Among participants who were not depressed (PHQ-9 score ≤ 9), C-DBS scores were the only predictor for ISI scores (β = 0.46, p < 0.001). ConclusionsaaDysfunctional beliefs about sleep in cancer patients were significantly associated with severity of insomnia, independent of depression. Sleep Med Res 2019;10(1):31-35