Component studies of psychological treatments of adult depression: A systematic review and meta-analysis

Clinical or methodological significance of this article: A recent report from the Institute of Medicine pointed once again at the need for identifying the key elements of psychosocial interventions that drive an intervention’s effect. Component studies are an important tool for examining how therapies work and they provide an elegant way to identify the active ingredients of psychotherapies. These studies decompose multicomponent therapies and compare the full therapy with a therapy in which one component is left out (dismantling studies) or in which a component is added to an existing therapy. We conducted a systematic review of component studies by searching an existing database of randomized trials examining the effects of psychological treatments of adult depression. This had the advantage that we probably missed few component, in contrast to earlier reviews, because component studies often do not use this design as index term.