Rationale, design and methods of the Cul-CM study: a protocol for cultural adaptation of contingency management in adults with stimulant use disorder.

INTRODUCTION

Stimulant use disorder is a growing contributor to drug poisoning and mortality in the USA, with disproportionate impact on black communities driven by stimulant-opioid polysubstance use and other structural barriers to treatment. Contingency management (CM) is the most effective evidence-based treatment for stimulant use disorder but remains poorly implemented especially in minoritised communities. Cultural adaptation represents a promising implementation strategy to improve acceptability, engagement and equity of CM while maintaining fidelity to core evidence-based programming.

METHODS AND ANALYSIS: The Cultural Adaptation of Contingency Management (Cul-CM) study is a multiphase, mixed-methods study designed to culturally adapt CM for black adults with stimulant use disorder and evaluate its preliminary outcomes in a pilot randomised controlled trial (RCT), guided by the PEN-3 cultural model and the ADAPT-ITT framework. Phase I consists of an assessment of clinician beliefs about CM implementation using the Extended Contingency Management Beliefs Questionnaire (CMBQ-CA+, with an exploratory Cultural Adaptation subscale) and a scoping review of CM adaptation for substance use disorder. Phase II employs PEN-3-informed individual interviews and focus groups to identify culturally salient determinants of CM uptake and engagement. Findings from Phases I and II, in addition to iterative expert and community advisory board reviews and feedback, will inform the development of a culturally adapted CM (CACM) protocol, which retains core effectiveness elements and modifies peripheral delivery elements of CM. Finally, the Phase III consists of a three-arm pilot RCT (n=60) comparing the CACM, standard CM and treatment as usual following a 1 week lead-in (priming) phase. Primary outcomes include stimulant abstinence and longest duration of continuous abstinence. Secondary outcomes include treatment acceptability, satisfaction, feasibility and retention. Cul-CM operationalises cultural adaptation as a systematic, theory-driven strategy to improve CM outcomes in adults with stimulant use disorder and promote equitable uptake in community treatment settings. Cul-CM represents a replicable framework for culturally adapting CM to ensure equitable access, engagement and improve outcomes.

ETHICS AND DISSEMINATION: Ethical approval was obtained from the Yale University Institutional Review Board. All participants will provide written informed consent. Study findings will be disseminated through peer-reviewed publications, scientific conferences and community-engaged channels to inform culturally responsive approaches to CM for stimulant use disorder.

TRIAL REGISTRATION NUMBER: NCT07443332.