"I don't want to take buprenorphine for the rest of my life": Acceptance and Commitment Therapy for a Client Struggling to Reduce Low-Dose Buprenorphine (a Hermeneutic Single-Case Efficacy Design).

The misuse of substances is often maintained by both physical and psychological factors. Opioid-substitution medications manage physical aspects of addiction; however, difficulties with emotional regulation and avoidance perpetuate continued substance misuse. In the UK, individuals who misuse substances are often excluded from mental health services, meaning these underlying difficulties are not addressed. Acceptance and Commitment Therapy (ACT) seeks to reduce emotional avoidance. A hermeneutic single-case efficacy design was used to evaluate the effects of ACT within drugs and alcohol service. Quantitative and qualitative data was critically analysed to understand factors involved in identified changes. Analysis recognised the client progressed towards two of three of their goals, related to motivation and anxiety. Their psychological flexibility also increased. ACT processes played a key role in this; however, the therapeutic relationship and psychopharmacological factors were also noted. Study limitations and clinical and research implications are discussed.