Tobacco cessation intervention for individuals with severe mental illness in Bangladesh, India, and Pakistan: protocol for a multi-country feasibility randomised controlled trial (SCIMITAR-SA)

Background: Tobacco is consumed by two-thirds of individuals with severe mental illness (SMI). Despite a high tobacco-related disease burden, there is a lack of evidence-based cessation interventions for individuals with SMI living in low- and middle-income countries. This study aims to evaluate the feasibility and acceptability of a culturally adapted behavioural intervention for tobacco cessation (SCIMITAR-SA) delivered in mental health services in Bangladesh, India, and Pakistan. Methods: A two-arm, parallel-group, individually randomised, multi-country feasibility trial will be conducted across six mental health facilities in urban centres. All trial participants will receive Very Brief Advice (VBA) and an educational leaflet from their clinical team. Additionally, those in the intervention arm will receive up to seven structured behavioural support sessions. Salivary cotinine and anabasine will be used to biochemically verify abstinence at seven months post-randomisation. Quantitative outcomes will assess feasibility of conducting a definitive trial, including recruitment and retention rates, session attendance, completeness of baseline assessments and outcome measures at four and seven months and use of health resources. An embedded process evaluation will explore the feasibility and acceptability of trial processes, and of the delivery and receipt of the VBA and SCIMITAR-SA interventions. Economic outcomes will assess the feasibility of collecting cost and resource-use data to inform a future definitive trial. Discussion: The SCIMITAR-SA trial will provide essential evidence on the feasibility of delivering culturally adapted cessation support for people with SMI in South Asia and inform scalable integration into routine psychiatric care across low- and middle-income settings. Registration: ISRCTN registry (ISRCTN91038721).