Common factors theory

However, according to one review, "it is widely recognized that the debate between common and unique factors in psychotherapy represents a false dichotomy, and these factors must be integrated to maximize effectiveness." In other words, "therapists must engage in specific forms of therapy for common factors to have a medium through which to operate." Common factors is one route by which psychotherapy researchers have attempted to integrate psychotherapies.

History

Saul Rosenzweig started the conversation on common factors in an article published in 1936 that discussed some psychotherapies of his time. John Dollard and Neal E. Miller's 1950 book Personality and Psychotherapy emphasized that the psychological principles and social conditions of learning are the most important common factors. Sol Garfield (who would later go on to edit many editions of the Handbook of Psychotherapy and Behavior Change with Allen Bergin) included a 10-page discussion of common factors in his 1957 textbook Introductory Clinical Psychology.

In the same year, Carl Rogers published a paper outlining what he considered to be common factors (which he called "necessary and sufficient conditions") of successful therapeutic personality change, emphasizing the therapeutic relationship factors which would become central to the theory of person-centered therapy. He proposed the following conditions necessary for therapeutic change: psychological contact between the therapist and client, incongruence in the client, genuineness in the therapist, unconditional positive regard and empathic understanding from the therapist, and the client's perception of the therapist's unconditional positive regard and empathic understanding.

In 1961, Jerome Frank published Persuasion and Healing, a book entirely devoted to examining the common factors among psychotherapies and related healing approaches. Frank emphasized the importance of the expectation of help (a component of the placebo effect), the therapeutic relationship, a rationale or conceptual scheme that explains the given symptoms and prescribes a given ritual or procedure for resolving them, and the active participation of both patient and therapist in carrying out that ritual or procedure.

After Lester Luborsky and colleagues published a literature review of empirical studies of psychotherapy outcomes in 1975, the idea that all psychotherapies are effective became known as the Dodo bird verdict, referring to a scene from Alice's Adventures in Wonderland quoted by Rosenzweig in his 1936 article; in that scene, after the characters race and everyone wins, the Dodo bird says, "everybody has won, and all must have prizes." Luborsky's research was an attempt (and not the first attempt, nor the last one) to disprove Hans Eysenck's 1952 study on the efficacy of psychotherapy; Eysenck found that psychotherapy generally did not seem to lead to improved patient outcomes. A number of studies after 1975 presented more evidence in support of the general efficacy of psychotherapy, but the question of how common and specific factors could enhance or thwart therapy effectiveness in particular cases continued to fuel theoretical and empirical research over the following decades.

The landmark 1982 book Converging Themes in Psychotherapy gathered a number of chapters by different authors promoting common factors, including an introduction by Marvin R. Goldfried and Wendy Padawer, a reprint of Rosenzweig's 1936 article, and further chapters (some of them reprints) by John Dollard and Neal E. Miller, Franz Alexander, Jerome Frank, Arnold Lazarus, Hans Herrman Strupp, Sol Garfield, John Paul Brady, Judd Marmor, Paul L. Wachtel, Abraham Maslow, Arnold P. Goldstein, Anthony Ryle, and others. The chapter by Goldfried and Padawer distinguished between three levels of intervention in therapy:

1. theories of change (therapists' theories about how change occurs);
2. principles or strategies of change;
3. therapy techniques (interventions that therapists suppose will be effective).

Goldfried and Padawer argued that while therapists may talk about their theories using very different jargon, there is more commonality among skilled therapists at the (intermediate) level of principles or strategies. Goldfried and Padawer's emphasis on principles or strategies of change was an important contribution to common factors theory because they clearly showed how principles or strategies can be considered common factors (they are shared by therapists who may espouse different theories of change) and specific factors (they are manifested in particular ways within different approaches) at the same time. Around the same time, James O. Prochaska and colleagues, who were developing the transtheoretical model of change, proposed ten "processes of change" that categorized "multiple techniques, methods, and interventions traditionally associated with disparate theoretical orientations," and they stated that their processes of change corresponded to Goldfried and Padawer's level of common principles of change.

In 1986, David Orlinsky and Kenneth Howard presented their generic model of psychotherapy, which proposed that five process variables are active in any psychotherapy: the therapeutic contract, therapeutic interventions, the therapeutic bond between therapist and patient, the patient's and therapist's states of self-relatedness, and therapeutic realization.

In 1990, Lisa Grencavage and John C. Norcross reviewed accounts of common factors in 50 publications, with 89 common factors in all, from which Grencavage and Norcross selected the 35 most common factors and grouped them into five areas: client characteristics, therapist qualities, change processes, treatment structure, and therapeutic relationship. In the same year, Larry E. Beutler and colleagues published their systematic treatment selection model, which attempted to integrate common and specific factors into a single model that therapists could use to guide treatment, considering variables of patient dimensions, environments, settings, therapist dimensions, and treatment types. Beutler and colleagues would later describe their approach as "identifying common and differential principles of change".

In 1992, Michael J. Lambert summarized psychotherapy outcome research and grouped the factors of successful therapy into four areas, ordered by hypothesized percent of change in clients as a function of therapeutic factors: first, extratherapeutic change (40%), those factors that are qualities of the client or qualities of his or her environment and that aid in recovery regardless of his or her participation in therapy; second, common factors (30%) that are found in a variety of therapy approaches, such as empathy and the therapeutic relationship; third, expectancy (15%), the portion of improvement that results from the client's expectation of help or belief in the rationale or effectiveness of therapy; fourth, techniques (15%), those factors unique to specific therapies and tailored to treatment of specific problems. Lambert's research later inspired a book on common factors theory in the practice of therapy titled The Heart and Soul of Change.

In the mid-1990s, as managed care in mental health services became more widespread in the United States, more researchers began to investigate the efficacy of psychotherapy in terms of empirically supported treatments (ESTs) for particular problems, emphasizing randomized controlled trials as the gold standard of empirical support for a treatment. In 1995, the American Psychological Association's Division 12 (clinical psychology) formed a task force that developed lists of empirically supported treatments for particular problems such as agoraphobia, blood-injection-injury type phobia, generalized anxiety disorder, obsessive–compulsive disorder, panic disorder, etc. In 2001, Bruce Wampold published The Great Psychotherapy Debate, a book that criticized what he considered to be an overemphasis on ESTs for particular problems, and he called for continued research in common factors theory.

In the 2000s, more research began to be published on common factors in couples therapy and family therapy.

In 2014, a series of ten articles on common factors theory was published in the APA journal Psychotherapy. The articles emphasized the compatibility between ESTs and common factors theory, highlighted the importance of multiple variables in psychotherapy effectiveness, called for more empirical research on common factors (especially client and therapist variables), and argued that individual therapists can do much to improve the quality of therapy by rigorously using feedback measures (during treatment) and outcome measures (after termination of treatment). The article by Stefan G. Hofmann and David H. Barlow, two prominent researchers in cognitive behavioral therapy, pointed out how their recent shift in emphasis from distinct procedures for different diagnoses to a transdiagnostic approach was increasingly similar to common factors theory.