Capuk, HueseyinAylaz, Rukuye2026-04-042026-04-0420251465-98911475-9942https://doi.org/10.1080/14659891.2024.2412584https://hdl.handle.net/11616/109235Background: The aim of this study was to identify how transtheoretical model-based motivational interviewing affects self-efficacy and belief perception in individuals with substance use disorder. Methods: The study was conducted between October 2021 and July 2022 using an experimental research model with pretest and posttest control group. The sample size was calculated using the G*Power 3.1.7 programme, and a total of 46 participants including 23 in the experimental group and 23 in the control group were included in the study. The data were collected using a Socio-demographic Characteristics Questionnaire prepared by the researcher, Self-Efficacy Scale (SES), and Beliefs about Substance Use Scale (BSU). Results: While the self-efficacy total mean score of the experimental group was 83.39 +/- 13.13 before the experimental, it increased to 91.43 +/- 11.17 after the experimental and a statistically significant difference was found between them (p < .05). BSU total mean score of the experimental group was 42.30 +/- 22.42 before the experimental and significantly decreased to 25.52 +/- 7.56 after the experimental, and a statistically significant difference was established between them (p < .05). Conclusion: This method was found to be effective in changing individuals' self-efficacy and beliefs about quitting substances.eninfo:eu-repo/semantics/closedAccessSubstance use disordermotivational interviewingself-efficacybeliefnurseArticle30688088710.1080/14659891.2024.24125842-s2.0-85205842794Q3WOS:001331217500001Q40000-0003-0542-3152