Emotional exhaustion and sleep-related worry as serial mediators between sleep disturbance and depressive symptoms in student nurses: A longitudinal analysis

Objective: The multi-wave longitudinal study was to explore the underlying mechanisms between sleep disturbance and depressive symptoms for up to 9.5 months among student nurses and to examine whether emotional exhaustion and sleep-related worry could be the mediators. Methods: 856 student nurses aged 15-24 years (mean age = 17.8 years; all female) were recruited from a nursing school. Participants reported demographic variables (age, sibling, location, health condition, family monthly income and parents' marital quality) at baseline (Time1), Body Mass Index, weekly exercise, sleep disturbance and depressive symptoms at 3-month into internship (Time2), emotional exhaustion and sleep-related worry at 6-month into internship (Time3), and depressive symptoms at 9.5-month follow-up (Time4). Mediation analyses with bootstrapping were conducted to investigate the mediating role of emotional exhaustion and sleep-related worry in the relationship between sleep disturbance and depressive symptoms. Results: Adjusted analyses suggested that the direct effect of sleep disturbance on depressive symptoms was not significant (beta = 0.026, SE = 0.069, p = .71). Mediation analyses revealed two significant indirect effects between Time2 sleep disturbance and Time4 depressive symptoms with the mediating effect of emotional exhaustion (beta = 0.019, SE = 0.009, BC95%CI [0.0036,0.0405]) and sleep-related worry (beta = 0.016, SE = 0.008, BC95%CI [0.0026,0.0337]) respectively. When testing serial multiple mediation, the specific indirect effect of sleep disturbance on depressive symptoms through both emotional exhaustion and sleep-related worry was significant (beta = 0.005, SE = 0.003, BC95%CI [0.0004,0.0123]). Conclusions: Emotional exhaustion and sleep-related worry were positively associated with sleep disturbance and depressive symptoms.