The relationship between sleep-related worry and insomnia among shift-working nurses: the serial mediation of depression and anxiety

Shift-working nurses frequently experience insomnia as a consequence of irregular work schedules. This study aimed to examine the psychological mechanisms through which sleep-related worry contributes to insomnia, focusing on the roles of depressive and anxious emotions. Using convenience sampling, data on demographics, sleep-related worry, depression, anxiety, and insomnia were collected from 611 shift-working nurses. Mediation analyses were then performed with SPSS 27.0 and the PROCESS macro. Results indicated that the total effect of sleep-related worry on insomnia was 0.255 (bias-corrected 95% CI [[0.227, 0.283]), and the direct effect was 0.188 (bias-corrected 95% CI [0.155, 0.221]), accounting for 73.73% of the total effect. The independent indirect effect through depression was statistically significant (b = 0.045, bias-corrected 95% CI [0.015, 0.075]). The serial mediation effect through depression followed by anxiety was also statistically significant (b = 0.019, bias-corrected 95% CI [0.001, 0.039]), jointly accounting for 26.27% of the total effect. In contrast, the independent indirect effect of anxiety was not significant (b = 0.003, bias-corrected 95% CI [0.000, 0.009]). These findings suggest that depression serves as a key mediator between sleep-related worry and insomnia. Anxiety, although not independently significant, contributes additively to insomnia when combined with depression. Interventions that prioritize reducing sleep-related worry and strengthening emotional regulation could improve sleep quality and overall health, ultimately supporting both physical and psychological well-being.