The current study aims at investigating the effectiveness of Cognitive Therapy and Acceptance and Commitment Therapy in a randomized controlled trial among patients with MDD in routine clinical practice. Further, the study will investigate whether each specific treatment approach is mediated by its proposed theoretical mechanism. Patients have to meet diagnostic criteria for nonpsychotic MDD as determined by the Structured Interview for DSM-IV. Each client will receive either Cognitive Therapy or Acceptance and Commitment Therapy that will last between 16 to 20 sessions. Based on previous results, it is expected that both treatment forms will prove beneficial for the patients.
