Effectiveness of adjunctive, personalised psychosocial intervention for non-response to opioid agonist treatment: Study protocol for a pragmatic randomised controlled trial

Introduction Opioid use disorder (OUD) is a debilitating and relapsing psychiatric disorder; opioid agonist therapy (OAT) is the front-line, evidence-supported treatment. A substantial number of patients relapse or continue to use heroin or other illicit drugs during OAT. There is considerable heterogeneity in the OAT-resistant sub-population, with many behavioural moderators of treatment response. We have developed a personalised psychosocial intervention (PSI) targeting these individuals. A formulation-guided assessment is linked to a toolkit of motivational, cognitive/behavioural and social support techniques. Change methods have been adapted from evidence-supported psychological therapies and are idiosyncratically tailored to the need and response. Methods In this single-centre, 18-week, parallel group, pragmatic randomised clinical trial, we will determine the clinical and cost-effectiveness of the PSI as an adjunctive intervention during OAT, in comparison to opioid agonist treatment-as-usual. We plan to recruit 368 adults. The primary outcome measure is the proportion of participants categorised as ‘responders’ at the end of the intervention (defined as self-reported abstinence from heroin and cocaine with no positive biological drug tests during the 28 days prior to the endpoint). Secondary outcomes include: percentage of days abstinent from heroin and cocaine in the 28 days before follow-up; treatment retention; therapy compliance; health and social functioning; exploratory genetic biomarkers; and analyses of treatment moderation and mediation. Conclusions This pragmatic controlled trial determines the effectiveness and cost-effectiveness of a personalised PSI for non-responding patients during OAT. Our intervention applies motivational, cognitive/behavioural and social support techniques adapted from evidence-based therapies. Findings will inform stratified delivery of OAT.