Understanding why therapy allegiance is linked to clinical outcomes.

Researchers and practitioners have long debated the meaning and importance of the relation between therapy allegiance and clinical outcomes. Leykin and DeRubeis (2009) make a meaningful contribution to this discussion and their observations will help sharpen future discourse on the topic. This commentary builds upon their observations and argues that efforts to identify and understand the mechanisms underlying the relation between therapy allegiance and therapy outcome may inform the ongoing debate and benefit the field of psychological therapy. Two potential mechanisms—investigators (via training) and therapists (via attitudes and motivation)—are reviewed and the potential yield from such research underscored.