This “Dodo bird verdict” (DBV) — everybody has won — has been applied to a long-time and never-ending debate about which psychotherapy approach is more effective in treating patients in need of psychotherapy (1), psychodynamic psychotherapy (PDPT), cognitive-behavioral psychotherapy (CBT), or one of the many other therapy modalities that exist in between and beyond and claim to be the best for all and everybody. Psychotherapists of all colors and proveniences have a clear answer to this question: Mine is the best because I believe it in and I am good at it…... The empirical side of this competition tells a different story. Whenever different psychotherapies were tested in clinical trials against another therapy of the same or different kind or against another control condition (see below), the effects of one therapy was not that much different from another therapy. Meta-analyses of today (2) confirm what Rosenzweig described in the classical DBV paper 80 years ago (1): All psychotherapies operate with similar assumptions, implement similar means, and generate similar results, based on what has been called “common factors” that are immanent to all psychotherapy traditions.
Randomized placebo-controlled trials are recognized as the gold-standard of evidence-based medicine but when it comes to psychotherapy research all that g litters is not gold. Translation of this standard from medicine to clinical psychology is fraught with difficulties. While a wealth of robust evidence shows that psychotherapy is effective for a range of mental health conditions the use of placebo controls to assess the effectiveness of specific psychological interventions faces serious conceptual and methodological challenges (Gaab et al., 2018). In this Opinion article we identify two under-appreciated placebo-related problems which substantially risk the validity of clinical trials in psychotherapy. The first is a common misconception about the nature of placebos; the second is the problem of double-blinding. We review current solutions and future prospects for the gold-standard in psychotherapy research.