The forest and the trees: relational and specific factors in addiction treatment

Aims Increased expectations for the use of evidence-based methods in addiction treatment have fueled a debate regarding the relative importance of ‘specific’ versus ‘common’ factors in treatment outcome. This review explores the influence of these factors on addiction treatment outcome. Methods The authors review and link findings from four decades of research on specific and general factors in addiction treatment outcome research. Findings Although few would argue that what one does in addiction treatment is immaterial, outcome studies tend to find small to no difference when specific treatment methods are compared with each other or with treatment as usual. In contrast, there are usually substantial differences among therapists in client outcomes, and relational factors such as therapist empathy and therapeutic alliance can be significant determinants of addiction treatment outcome. Conclusions In addiction treatment, relational factors such as empathy, which are often described as common, non-specific factors, should not be dismissed as ‘common’ because they vary substantially across providers and it is unclear how common they actually are. Similarly they should not be relegated to ‘non-specific’ status, because such important relational influences can be specified and incorporated into clinical research and training.