Background: Heroin-assisted treatment (HAT) is the provision of prescribed heroin under medical supervision. Clinical trials have shown that HAT is effective in reducing illicit drug use, criminal activity, and improving health and wellbeing. We aimed to understand the barriers and facilitators to implementing Scotland’s first HAT service, exploring the views and experiences of patients, staff, and other key stakeholders.

Methods: A service logic model was developed and used to identify key processes in the patient pathway. Baseline and follow-up interviews were carried out with nine patients (11 interviews) and 13 staff (22 interviews) over the course of two years. Barriers and facilitators to key processes identified were then used in multiple stakeholder events to develop recommendations.

Results: Patients who were still engaged with HAT after one year experienced substantial improvements including decreased heroin use, and improved health, wellbeing and social functioning. Barriers to implementation included: highly complex needs of the patient group; high levels of polydrug use; service intensity; staff turnover; COVID-19 restrictions; and service design/location. Facilitators included: individualised care packages; relationship building between staff and patients; optimal diamorphine dosage alongside OAT; holistic support; a non-punitive, harm reduction service focus; appropriately skilled staff; diverse referral pathways; and co-location with other relevant services.

Conclusion: Heroin-assisted treatment was safely implemented for patients with complex needs who had previously been unable to meaningfully engage in community drug treatment services. Findings were used to develop recommendations that will guide the establishment, development, and maintenance of HAT across Scotland and the UK.