Grant: Project Grant

While many individuals experience transient sleep disturbances, about 9% of the Canadian population suffers from chronic insomnia. Although stress is recognized as a common cause for the onset of insomnia, the role of chronic stress in the maintenance of insomnia over time is less well understood. One reason is that there are individual differences in stress reactivity; that is, some people experience stronger bodily responses to stress than others. This means that some individuals are more vulnerable to experience insomnia in response to stress than others. Furthermore, most of the past studies have not examined the types of stressors that are chronic in nature. Moreover, some studies suggest that not only can stress lead to poor sleep, but poor sleep is also associated with increased stress. To better understand the role of chronic stress in insomnia, we will follow a group of insomniacs who will receive a psychological treatment for insomnia. At the beginning of the study, insomniacs will complete assessments of chronic stress, stress reactivity, and current insomnia symptoms. Then, the participants will be assigned to either a cognitive-behavioural therapy for insomnia or to a waiting period. Changes in insomnia and chronic stress will be assessed after treatment as well as 12 months later. This study will allow us to examine whether chronic stress is related to changes in insomnia over time, whether insomnia treatment reduces chronic stress, and whether individuals with high stress reactivity are more susceptible to the impact of chronic stress on sleep. Our overall goal is to identify a subgroup of insomniacs more susceptible to the impact of chronic stress on insomnia that may benefit from treatment targeting stress reactivity.