Endogenous Oxytocin and Depressive Symptoms in Drug Abstainers: The Roles of Perceived Social Support and Drug Abstinence Self-Efficacy.

Purpose: Depressive symptoms is highly prevalent among individuals in drug abstinence and substantially hinders rehabilitation. Grounded in the biopsychosocial model, this study examined the associations among endogenous oxytocin, perceived social support, drug abstinence self-efficacy, and depressive symptoms among drug abstainers. Patients and Methods: A cross-sectional study was conducted with 339 participants recruited from a compulsory drug abstinence center in China in November 2023. Salivary oxytocin levels were assessed using enzyme immunoassay. Participants completed validated self-report measures of depressive symptoms (PHQ-9), perceived social support (PSSS), and drug abstinence self-efficacy (SELD). Data were analyzed using SPSS 26.0 and the PROCESS macro with 5000 bootstrap samples to test the proposed mediation and moderated mediation models. Results: Higher endogenous oxytocin was associated with lower depressive symptoms and greater perceived social support. Perceived social support partially mediated the oxytocin-depressive symptoms association. Drug abstinence self-efficacy moderated both the direct and indirect paths, with stronger associations observed among individuals with higher self-efficacy. Conclusion: Endogenous oxytocin may be a protective correlate of depressive symptoms in drug abstainers, partly through its association with perceived support. These associations are amplified by greater drug abstinence self-efficacy. The findings bridge biological, social, and cognitive perspectives, proposing practical intervention approaches to mitigate depressive symptoms and enhance abstinence outcomes for drug abstainers.