On the importance of identifying mechanisms and active ingredients of psychological treatments.

This commentary addresses the thought-provoking article by Lorenzo-Luaces (in press). We review areas of both agreement and disagreement with the author's points, noting that readers should not infer that research into active ingredients and mechanisms is pointless. We conclude with a call for more research into the mechanisms of therapeutic change and the active ingredients of therapeutic interventions, with the aim of disseminating treatments that are both effective and efficient.