Delivering, implementing and receiving an enhanced smoking cessation service for people with severe mental illness in the North East and North Cumbria: A mixed-methods study of barriers and facilitators

Background: This study evaluated barriers and facilitators to implementing, delivering, and participating in an enhanced smoking cessation service for individuals with severe mental illness (SMI). The service, delivered across four pilot sites in the North East and North Cumbria (NENC) of England between April 2023 and March 2024, used a primary care referral model and a 20-week ‘cut down to quit’ approach combining behavioural and pharmacological support.Methods: A mixed methods approach was used, including analysis of aggregated recruitment and outcome data, coding documents for Behaviour Change Techniques (BCTs), a quantitative survey with purposively recruited service providers (n = 20), and qualitative interviews with service providers (n = 14) and service users (n = 4). The Theoretical Domains Framework (TDF) and Capability, Opportunity, and Motivation for Behaviour (COM-B) model informed survey and interview design and analysis. A purposively recruited Lived Experience Advisory Panel (LEAP) (n = 6) contributed to protocol development, study materials, and interpretation of findings.Results: In Pilot Sites A and B, nearly half of service users who set a quit plan had quit smoking at 28 days (~45%). Documentary analysis found the most common BCTs were pharmacological support, adding objects to the environment, and restructuring the environment. Survey findings indicated that providers had the capability, opportunity, motivation, and intention to deliver the service and found it acceptable, though perceptions of required effort varied. Interview findings showed that facilitators for service implementation were primarily linked to motivation (e.g., positive user feedback, staff motivation), whereas barriers were linked to capability (e.g., data recording) and opportunity (e.g., primary care links). For service delivery and participation, facilitators linked to capability (e.g., tailoring support, understanding social determinants) and motivation (e.g., benefits of quitting, goal setting).Conclusions: Service delivery was perceived as effective due to flexibility and tailored support. Recommendations for improving service implementation should focus on strengthening primary care engagement and referral pathways, enhancing training and skills development for Stop Smoking Advisors, and improving data management systems and evidence gathering early in implementation. Future research should engage more service users and referrers to better understand barriers to service implementation and participation.