The Relationships Among Sleep Quality and Chronotype, Emotional Disturbance, and Insomnia Vulnerability in Shift Nurses

BACKGROUND: Shift work is a prominent feature of most nursing jobs. Although chronotype, emotional disturbance, and insomnia vulnerability are important factors for patients with insomnia in general, their effects on shift nurses are unknown. PURPOSE: This study explores the relationships between the sleep quality of shift nurses and the variables of chronotype, emotional disturbance, and insomnia vulnerability. METHODS: A survey was conducted with 398 shift nurses in a medical center. Chronotype, emotional disturbance, insomnia vulnerability, and sleep quality were evaluated using the Smith Morningness-Eveningness Questionnaire, the Brief Symptom Rating Scale, the Ford Insomnia Response to Stress Test, and the Pittsburgh Sleep Quality Index, respectively. RESULTS: On the Pittsburgh Sleep Quality Index, 70.1% of the participants scored higher than 5. Multiple regression analysis revealed that, together with night shift work (b [SE] = 1.05 [0.35], p = .003), higher levels of emotional disturbance (b [SE] = 0.30 [0.05], p < .001) and higher insomnia vulnerability (b [SE] = 0.18 [0.03], p < .001) were predictors of poor sleep quality and that chronotype was not a predictor of poor sleep quality. The multiple mediator model indicated that emotional disturbance significantly mediated an indirect effect of evening chronotype preference on poor subjective sleep quality (one subscale of the Pittsburgh Sleep Quality Index). CONCLUSIONS/IMPLICATIONS FOR PRACTICE: In addition to shift patterns, emotional disturbance and high insomnia vulnerability are factors that may be used to identify shift nurses who face a higher risk of sleep disturbance. Because evening chronotype may indirectly influence subjective sleep quality through the pathway of emotional disturbance, further research into the mechanism that underlies this pathway is warranted.