Referring to the future of psychotherapy research calls for some reflections on its past and present. Historically, psychoanalysis was the “first force,” and was followed by behaviorism (second force) as a reaction to the “unscientific” nature of psychoanalysis theory and lack of connection to observable phenomena. Some prominent behaviorists, however, would later expand their models to incorporate cognitions, as proposed by Albert Ellis, Aaron Beck and others, and which emphasized the importance of mental representation of the stimuli as central elements to psychopathology. The third force emerged after World War II and was referred to as the humanistic and experiential approaches because these theoretical approaches were based on the humanistic philosophers. Humanistic and experiential treatments were mainly represented by person-centered therapy developed by Carl Rogers, and Gestalt therapy developed by Frederick Perls. There have also been the fourth (feminist and multicultural theories) and the fifth (post-modern and constructivist theories) forces .
Importantly, the approaches encompassed by each force continued to evolve, resulting in multiple spinoffs. Thus, it is not surprising that the huge number of approaches originated from the above-mentioned forces in psychotherapy called for the need for assessing the efficacy of such treatments, and gave rise to the “empirically validated treatments” project , which reduced the number of validated psychotherapies to the fewer than 50 which demonstrated superiority over some type of placebo by at least two RCTs. The word “validated” was later replaced with “supported,” becoming “empirically supported treatments” (EST).
Another movement derived from medicine, namely evidence-based practice (EBP), was adopted by psychologists (APA Presidential Task Force on Evidence-Based Practice, ) who defined EBP as “the integration of the best available research with clinical expertise in the context of patient characteristics, culture, and preferences,” and endorsed the multiple types of evidence that contribute to effective practice in psychology, such as efficacy, effectiveness, cost-effectiveness, cost-benefit, epidemiology and treatment utilization .
Another consequence of the huge number of single-school psychotherapy approaches was a movement that started in the 1970s and gave rise to what came to be known as the psychotherapy integration movement, which encompassed common factors (an aspect of psychotherapy that is present in most, if not all, approaches to treatment), theoretical integration (synthesis of two or more theories into a single conceptualization), technical integration (use of techniques drawn from several different therapeutic approaches), and assimilative integration (one theoretical position is accompanied by a willingness to incorporate techniques from other therapeutic approaches) [11, 12].
Thus, my understanding is that what the future holds for psychotherapy research is the challenge of answering or clarifying many questions still incompletely explored, some of which are: How does psychotherapy work? Are some psychotherapies more effective than others? What is the role of theory in psychotherapy? Is psychotherapy integration a solution for the complexities of the field? Some of these questions are approached in the books of the Theories of Psychotherapy Series, organized by Carlson and Englar-Carlson . For those interested in knowing more, I suggest you read The basics of psychotherapy: An introduction to theory and practice, followed by Psychotherapy integration, before going to each individual psychotherapy theory.
Limitations to psychotherapy integration, in my opinion, may be more in excessive reliance of psychotherapists on their theoretical allegiances and their unwillingness to talk to those from other theories than those from inside the field itself.