BACKGROUND AND AIMS: Despite the well-documented benefits of opioid substitution treatment (OST) in treating opioid dependence (OD), many people diagnosed with OD desire to live a drug-free life. The transition to abstinence involves detoxification: a gradual dose reduction of OST to zero milligrams. Despite these aspirations, only a minority of patients undertake detoxification, and successful completion remains limited. This mixed-methods systematic review aimed to identify the barriers and facilitators to detoxification from OST, to help provide a better understanding of what can be done to support patients and improve outcomes in OD.

METHODS: Four databases were searched until 22 January 2025: PubMed, Embase, APA PsycINFO and CINAHL. Qualitative, quantitative and mixed methods studies of individuals with a diagnosis of OD undergoing detoxification from OST, or staff responsible for providing the treatment, were included. Studies of only pharmacological interventions were excluded. An integrated approach to data synthesis was used, transforming quantitative data into textual descriptions to integrate them with qualitative data and form one set of themes. Joanna Briggs Institute checklists were used to assess the quality of included papers.

RESULTS: From 1999 studies identified, 41 papers were deemed eligible. Studies originated from the USA (22), UK (7), Sweden (6), Canada (1), Ireland (1), Norway (1), Switzerland (1), Australia (1) and China (1). The medications explored included methadone (28), buprenorphine (5), both forms (6) and unspecified OST (2). Studies were conducted in outpatient settings (29), inpatient settings (7), mixed settings (4) and a prison setting (1). Participants included patients (37), treatment providers (1) and mixed populations (3). Factors affecting detoxification were present at an individual and structural level, with overlap between influences at the initiation and completion phases. Eight themes emerged, comprising psychological and emotional factors (particularly around fear of detoxification), personal motivation, withdrawal symptoms, clinical and demographic factors, environmental factors, social factors, professional support and treatment models/interventions. 54% of included studies were rated high quality, and 37% of medium quality.

CONCLUSION: Detoxification from opioid substitution treatment appears to be commonly hindered by fear, emotional resurgence, low confidence, environmental turbulence, negative social influences and insufficient professional/pharmacological support, while facilitators include psychological readiness, life stability, supportive relationships, psychological interventions, inpatient facilities and adjunctive medications.