Abstract:
Harvey’s (2002) cognitive model of insomnia posits that subjectively experienced poor sleep and sleep-related impairment during the day arise from negatively toned cognitive activity consisting of worry and rumination. Although these processes are often treated as interchangeable, evidence suggests that they constitute distinct constructs, and the need for clarifying their individual properties in driving self-reported sleep problems has been highlighted. This study investigated whether worry and rumination differentially predict sleep disturbance and sleep-related impairment in an online population-based sample. Hierarchical regression models entered the cognitive process variables in a stepwise fashion to assess their relative strength in explaining sleep outcomes after controlling for demographics, circadian factors, health status, and self-estimated sleep parameters. Separate analyses were conducted using sleep-specific and general trait measures of worry and rumination. In the sleep-specific analysis, only worry significantly predicted sleep disturbance after all covariates were entered, whereas rumination was entered after worry in the model predicting sleep-related impairment. In the analysis of general worry and rumination, each variable significantly predicted both sleep outcomes. Worry was a stronger predictor of sleep disturbance, whereas rumination was a stronger predictor of sleep-related impairment. Findings suggest a role for rumination separate from that of worry in perpetuating daytime impairment attributed to poor sleep. The results also highlight a need to more closely examine how cognition and other factors contribute to daytime symptomology in insomnia.
