Daily Sleep-Stress Reactivity and Functional Impairment in World Trade Center Responders

Background: How sleep is impacted by stress ("sleep reactivity to stress") and how stress is impacted by sleep ("stress reactivity to sleep") are trait-like characteristics of individuals that predict depression, anxiety, and insomnia. However, pathways between reactivity and functional impairment (e.g., impairment in social relationships and interpersonal functioning) have not been explored, which may be a critical pathway in understanding the link between reactivity and the development of psychological disorders. Purpose: We examined associations between reactivity and changes in functional impairment among a cohort of 9/11 World Trade Center responders. Methods: Data from 452 responders (Mage = 55.22 years; 89.4% male) were collected between 2014 and 2016. Four baseline sleep and stress reactivity indices (i.e., sleep duration and efficiency reactivity to stress; stress reactivity to sleep duration and efficiency) were calculated from 14 days of sleep and stress data using random slopes from multilevel models. Functional impairment was assessed approximately 1 year and 2 years after baseline via semi-structured interviews. Latent change score analyses examined associations between baseline reactivity indices and changes in functional impairment. Results: Greater baseline sleep efficiency reactivity to stress was associated with decreases in functioning (β = -0.05, p=.039). In addition, greater stress reactivity to sleep duration (β = -0.08, p=.017) and sleep efficiency (β = -0.22, p<.001) was associated with lower functioning at timepoint one. Conclusion: People who are more reactive to daily fluctuations in stress and sleep have poorer interpersonal relationships and social functioning. Identifying individuals with high reactivity who could benefit from preventative treatment may foster better social integration.