Effectiveness of a tobacco cessation intervention for individuals with severe mental illness in South Asia

INTERVENTION: Randomisation will be conducted on a 1:1 basis using a block stratified sequence, generated by an independent statistician at York Trials Unit (using STATA v19 or later). Stratification will be based on study location and type of tobacco use (smoked tobacco products only, smokeless tobacco products only, or dual use). The randomisation sequence will be implemented using a secure, centralised Google Form–based system developed by the software developers at York Trials Unit. Following completion of baseline assessments, the research assistant (based at trial facility) will submit a randomisation request via a google form where the participant’s unique study ID and stratification factors will be specified. Upon submission, the study arm will be allocated to the participant’s ID and the RA will be informed of this via an automated email. The underlying allocation sequence will be managed by the software developers at York Trials Unit and not made accessible to any participant facing research staff in order to maintain concealment. Very Brief Advice (VBA): All trial participants will receive VBA, delivered by health professionals during outpatient visits in interactions lasting up to 1 minute. It will include a brief conversation on tobacco use status (smoked and/or smokeless), advice to quit and providing a self‐help educational leaflet that has been adapted from our previous research. SCIMITAR‐SA intervention: Participants allocated to the intervention arm will receive SCIMITAR‐SA intervention in addition to the VBA. The SCIMITAR‐SA intervention is a culturally adapted, patient‐centred behavioural tobacco cessation programme designed for individuals with severe mental illness (SMI) in South Asian contexts (Bangladesh, India, and Pakistan). Adapted from SCIMITAR‐UK and the NCSCT Standard Treatment Programme, it addresses both smoked and smokeless tobacco use, dual‐use patterns, and local cultural norms. It consists of seven tailored behavioural modules delivered using corresponding patient‐facing flipbooks, spanning pre‐quit, quit, and post‐quit stages. Initial appointments for pre‐quit modules are conducted face‐to‐face, with subsequent sessions offering flexible remote options. Participants target a quit date within 30 days of enrolment, supported by core techniques such as goal setting, relapse prevention, and guidance on accessible Nicotine Replacement Therapy. CONDITION: Adult users of tobacco (smoked and/or smokeless) with a confirmed diagnosis of one or more Severe Mental Illness(SMI) including (schizophrenia, schizoaffective disorder, psychosis, bipolar disorder with out without psychosis, or severe depression with/without psychotic features), who are willing to quit all forms of tobacco use within the next 30 days. ; Mental and Behavioural Disorders PRIMARY OUTCOME: Continuous abstinence from all tobacco products measured using self‐reported tobacco abstinence and biochemical verification through salivary cotinine and anabasine levels at 7 month follow up SECONDARY OUTCOME: Barriers and drivers to the delivery, implementation and potential future scale‐up of SCIMITAR‐SA, as well as the mechanisms of action in achieving tobacco cessation, measured using qualitative interviews and focus group discussion (FGDs) at 4 months post‐randomisation Continuous abstinence from all tobacco products will be measured using self‐report, with the relevant information collected by administering a questionnaire to participants at 4, 7 and 13 months post‐randomisation. Changes in physical and mental health will be assessed using the SF‐12 questionnaire, psychiatric symptom severity using the Brief Psychiatric Rating Scale (BPRS), quality of life using the EQ‐5D‐5L questionnaire, and anthropometric measures in accordance with the WHO STEPwise approach to Surveillance (STEPS) protocol. These outcome measures will be measured at 4, 7, and 13 months post‐randomisation Cost‐effectiveness and impact on health inequalities measured using self‐reported health resource use, with the relevant information collected by administering a questionnaire to participants at 4, 7, and 13 months post‐randomisation INCLUSION CRITERIA: Adults aged =18 years receiving or referred for outpatient mental health services who: 1. Have a psychiatrist‐diagnosed severe mental illness (schizophrenia, schizoaffective disorder, psychosis, bipolar disorder with out without psychosis, or severe depression with/without psychotic features) 2. Have used smoked and/or smokeless tobacco for =6 months and on =25 of the past 30 days 3. Are clinically stable, able to provide informed consent, and have had no more than a 25% medication dose change or ECT/neuromodulation in the past 3 months 4. Is the only participant from their household 5. Are willing to quit all tobacco within 30 days and can attend at least three counselling sessions. The first sessions of the first three modules must be face‐to‐face; other sessions may be remote if needed