Demographic information for sample.

Introduction and aims
In the specialized nursing setting, nurses are susceptible to developing negative mental health issues. Such conditions among nurses can potentially result in unfavorable medical outcomes. Consequently, this study aims to explore the role of social support in regulating between sleep and mental health in nurses.
Methods
A cross-sectional study was carried out in September 2022 on 1219 nurses in Quanzhou. The study comprised general demographic information and utilized various questionnaires, namely the Social Support Rate Scale (SSRS), Pittsburgh Sleep Quality Index Questionnaire (PSQI), Generalized Anxiety Disorder Questionnaire (GAD-7), and Patient Health Questionnaire-9 (PHQ-9). The data analysis was performed using t-tests, ANOVAs, Pearsons correlations and hierarchical regression analyses in SPSS software.
Results
Results show that significant associations of sleep quality and social support with anxiety and depression. Simple slope analysis shows that under low levels of social support, sleep quality has a positive impact on anxiety(β = 0.598) and depression(β = 0.851), and the impact is significant. Under high levels of social support, sleep quality also has a positive impact on anxiety(β = 0.462) and depression(β = 0.578), but the impact is smaller. This indicates that as the level of social support increases, the positive predictive effect of sleep quality on anxiety and depression gradually diminishes.
Conclusions
Social support has the potential to alter the impact of sleep quality on anxiety and depression. Therefore, healthcare policymakers need to focus on enhancing the level of social support and mitigating the impact of poor sleep on anxiety and depression.