Expectation focused and frequency enhanced cognitive behavioural therapy for patients with major depression (EFFECT): a study protocol of a randomised active-control trial.

introductionThe effectiveness of psychotherapy in depression is subject of an ongoing debate. The mechanisms of change are still underexplored. Research tries to find influencing factors fostering the effect of psychotherapy. In that context, the dose-response relationship should receive more attention. Increasing the frequency from one to two sessions per week seems to be a promising start. Moreover, the concept of expectations and its influence in depression can be another auspicious approach. Dysfunctional expectations and the lack of their modification are central in symptom maintenance. Expectation focused psychological interventions (EFPI) have been investigated, primarily in the field of depression. The aim of this study is to compare cognitive behavioural therapy (CBT) once a week with an intensified version of CBT (two times a week) in depression as well as to include a third proof-of-principle intervention group receiving a condensed expectation focused CBT. METHODS AND ANALYSIS: Participants are recruited through an outpatient clinic in Germany. A current major depressive episode, diagnosed via structured clinical interviews should present as the main diagnosis. The planned randomised-controlled trial will allow comparisons between the following treatment conditions: CBT (one session/week), condensed CBT (two sessions/week) and EFPI (two sessions/week). All treatment arms include a total dose of 24 sessions. Depression severity applies as the outcome variable (Beck Depression Inventory II, Montgomery Asberg Depression Rating Scale). A sample size of n=150 is intended. ETHICS AND DISSEMINATION: The local ethics committee of the Department of Psychology, Philipps-University Marburg approved the study (reference number 2020-68 v). The final research article including the study results is intended to be published in international peer-reviewed journals. TRIAL REGISTRATION NUMBER: German Clinical Trials Registry (DRKS00023203).