Anxiety and sleep quality in Chinese persons with a substance use disorder: A moderated mediation model of rumination and mindfulness

A moderated mediation model was used to test how anxiety influences sleep quality via rumination, and when the association between anxiety, sleep quality and rumination is most potent in Chinese persons with a substance use disorder. The cohort comprised 104 registered substance users recruited from two compulsory drug treatment institutions in the city of Guangdong in Eastern China. All subjects completed the Beck Anxiety Inventory, the Ruminative Response Scale, the Mindful Attention Awareness Scale and the Pittsburg Sleep Quality Index. Path analyses were performed in PROCESS for SPSS to test the mediating effect of rumination on the association between anxiety and sleep quality. Finally, the conditional process analysis was performed to test how the moderating effect changes under different levels of mindfulness. The mediating analysis documented that the effect of anxiety on sleep disorders was mediated via rumination. Mindfulness was found to act as a moderator on the relationship between anxiety and poor sleep quality. Conditional process analysis revealed that anxiety had a significant impact on poor sleep quality across low, middle and high levels of mindfulness; however, the indirect effect of rumination on the relationship between anxiety and poor sleep quality was just moderated by mindfulness on low and middle levels of mindfulness. These findings deepen prior studies by explaining (1) how anxiety is associated with sleep quality via rumination, as well as (2) the circumstances in which the correlated effect is determined by mindfulness among substance users. Therefore, contribute to the existing literature.