Background: Up to 80% of patients experience insomnia as a result of cancer. Insomnia in cancer patients can be multifactorial due to tumor biology, stress associated with diagnosis, cytotoxic treatments, and side effects of cancer. Unfortunately, most of these causes are not modifiable. Dysfunctional beliefs about sleep include faulty beliefs and perceptions about sleep and are potentially modifiable. This study aimed to examine the extent to which dysfunctional beliefs contribute to the evolution of insomnia in cancer patients.

Methods: 141 breast cancer patients provided medical information, completed Insomnia Severity Index (ISI), Dysfunctional Beliefs About Sleep (DBAS-16) (e.g., “I am worried that I may lose control over my abilities to sleep”) and the European Organization for Research and Treatment of Cancer (EORTC-QLQ-BR23) Health-Related Quality of Life (HRQL).

Results: On average, patients were 50 years of age (SD=10.81); All of the participants were receiving chemotherapy; 75.6% had Stage I or II breast cancer. Compared to patients with primary insomnia in a normative sample, cancer patients had higher levels of dysfunctional beliefs t(468) = 2.07, p=.04. Higher DBAS was associated with more severe insomnia (r=.42, p<.001), even after controlling for age and medical variables (adj R2=.18, p<.001). DBAS was also associated with higher dyspnea (r=.25, p=.003), higher number of cancer-related side effects (r=.21, p=.01), breast symptoms (r=.20, p=.02), more fatigue (r=.42, p<.001), worse body image (r=-.33. p<.001), and financial difficulties (r=.17, p=.04). Additionally, higher scores on DBAS were associated with negative future time perspective (r=-.27, p=.001), worse global health status (r=-.20, p=.02), reductions in physical functioning (r=-.18, p=.03), decline in role functioning (r=-.19, p=.02), worse emotional functioning (r=-.36, p<.001), and lower cognitive functioning (r=-.40, p<.001).

Discussion: These results suggest that dysfunctional beliefs about sleep are associated with insomnia even after controlling for medical variables in breast cancer patients receiving chemotherapy. Dysfunctional beliefs were also linked with worse HRQL symptoms. Addressing dysfunctional beliefs, which is a modifiable risk factor that can respond to psychotherapy, may lead to a decrease in insomnia and improvement in HRQL. This merits further study.