The mediating effects of depressive symptoms and sleep quality on the relationship between the non-medical use of prescription drugs and suicidal behaviors among Chinese adolescents

Background: The nature of the relationship between the non-medical use of prescription drugs (NMUPD) and suicide has not been clearly elucidated. Some studies have suggested that the relationship between substance use and suicidal ideation may be spurious and could be explained by other variables. Methods: A school-based cross-sectional study was performed in Guangzhou. A total of 5853 students completed questionnaires and were included in the study. NMUPD, alcohol use, illicit drug use, depressive symptoms, sleep quality, and suicidal behaviors were assessed. The mediating effects of depressive symptoms and sleep quality on the relationship between NMUPD and suicidal behaviors were examined using a structural equation model. Results: In the simple model without mediation, a positive relationship between NMUPD and suicidal behaviors in adolescents was found, which was independent of effects from the use of other substances. Both depressive symptoms and sleep quality were significant mediators of this relationship. Conclusion: Public health and educational professionals should survey depressive symptoms and sleep quality and provide interventions when managing suicidal behaviors among adolescents engaging in NMUPD.