UC San Diego

Breast cancer patients have a high incidence of co-morbid chronic insomnia which frequently persists into survivorship. The mechanism behind this insomnia is poorly understood, yet maladaptive responses to the sleep disturbance resulting from an acute stressor are implicated in cognitive models of insomnia. Evidence suggests that health anxiety, pre-sleep cognitive arousal and compensatory sleep effort may predispose and/or perpetuate psychophysiological insomnia. These mechanisms have not been examined in patients with breast cancer, but if present, may be used to identify individuals at risk for developing chronic insomnia as well as inform intervention. Twenty women recently diagnosed with breast cancer and scheduled for adjuvant chemotherapy (age M = 54.6, SD = 7.9, range = 36-64) and 20 healthy age-matched women without history of breast cancer (age M = 53.6, SD = 7.5, range = 38-69) completed self-assessments and 72-hour wrist actigraphy on two occasions:(a) baseline, which for breast cancer patients was prior to start of chemotherapy (BL); and (b) at a subsequent occasion during or yoked to the last week of cycle 4 of chemotherapy (C4). Two-factor ANOVA revealed that at BL and C4 both groups reported similar levels of insomnia in addition to health anxiety, pre-sleep cognitive arousal and compensatory sleep effort. Actigraphic sleep and menopausal symptoms were also similar. Linear regression-based mediation analyses revealed that at BL, both groups demonstrated an association between health anxiety, compensatory sleep effort and insomnia. At C4, both groups demonstrated an association between compensatory sleep effort, pre-sleep cognitive arousal and insomnia. Additionally, compensatory sleep effort mediated links between health anxiety and insomnia, and pre-sleep cognitive arousal and insomnia. The results validate cognitive models of insomnia and provide support for targeting health anxiety, pre-sleep cognitive arousal and compensatory sleep effort as risk factors for insomnia in women with and without breast cancer