Stigma from healthcare professionals and care-limiting behaviors in individuals with substance use disorders: a mixed-methods study.

Background: Stigmatization of individuals with substance use disorders (SUDs) by healthcare professionals (HCPs) is a recognized problem, but its direct impact on patient treatment choices has not been systematically quantified. We aimed to provide first robust, quantitative metrics of non-disclosure, treatment avoidance, and treatment discontinuation for any medical treatment directly attributable to HCP stigma and to explore the lived experiences underpinning these behaviors. Methods: We conducted a prospective mixed-methods study with 119 adult inpatients with SUDs at a German university hospital (2021-2024). A self-developed questionnaire assessed stigma-related behaviors and their association with self-stigmatization. Qualitative data were analyzed using reflexive thematic analysis (RTA). A person with lived experiences contributed to writing up the manuscript. Findings: 49.6% (95% CI 40.3-58.9; n = 59/119) reported non-disclosure of substance use, 36.1% (95% CI 27.5-45.5; n = 43/119) avoided necessary medical treatment, and 29.4% (95% CI 21.4-38.5; n = 35/119) discontinued treatment due to stigma. Internalized stigma significantly predicted all three outcomes (aORs 1.055-1.075, p ≤ .001). RTA identified "Institutional Stigma" (addiction as a "moral failing"), "Barriers to Care" (obstacles to respectful treatment), and "Cost of Disclosure" (negative consequences such as hostility after revealing substance use). Interpretation: Stigma from HCPs is a quantifiable contributor of treatment disengagement, representing a direct threat to patient safety and a major contributor to the SUD treatment gap. These findings underscore the urgent need for evidence-based interventions, including training HCPs across all specialties in non-stigmatizing communication, to improve healthcare engagement for this vulnerable population and narrow the substantial treatment gap. Funding: None.