Duncan, Miller, Wampold, and Hubble (2010), Lambert (2013): "the average treated person is better off than about 80% of the untreated sample."
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Lambert, M. J., & Kleinstäuber, M. (2016). When people change, and its relation to specific therapy techniques and common factors. Verhaltenstherapie, 26(1), 32-39.
Using a placebo control allows one to eliminate patient expectations as a rival hypothesis that could ac-count for treatment effects...
The body of literature that has now been amassed shows predictable results: Patients in so-called placebo control groups typically show greater improvement than patients who are assigned to a wait list or no-treatment control group (e.g., Barker et al. [1988]; Bowers and Clum [1988]; Dush [1986]; Prioleau et al. [1983]; Sheperd [1984]). In a large-scale study of the literature, Lipsey and Wilson [1993] addressed the placebo issue as part of their extensive review of meta-analyses. The results of this review suggested that theoretically-based treatments are clearly superior to both no-treatment and placebo treatments. They concluded that ‘there are quite likely some generalized placebo effects that contribute to the overall effects of psychological treatment, but their magnitude does not seem sufficient to fully account for those overall effects’ (pp. 1196–1197).
In another review of the placebo effect, Grissom [1996] examined the relationship of therapy to control, therapy to placebo, placebo to control, and therapy to therapy across 46 meta-analytic reviews. The overall results ‘are consistent with the view that the ranking for therapeutic success is generally therapy, placebo, and control (do-nothing or wait)’ in that order (p. 979). Lambert and Ogles [2004] estimate of a placebo effect size (ES) is nearly identical to that reported by Lipsey and Wilson [1994] (ES = 0.44) and Grissom [1996] (ES = 0.48). These data suggest that the placebo patient will move to the 60th percentile of no-treatment controls, while the average psychotherapy patient moves to the 80th percentile.
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Lambert, M. J. (2015). Effectiveness of Psychotherapeutic Treatment. Resonanzen–E-Journal für biopsychosoziale Dialoge in Psychosomatischer Medizin, Psychotherapie, Supervision und Beratung, 3(2), 87-100.
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Lambert, M. J. (2005). Early response in psychotherapy: Further evidence for the importance of common factors rather than “placebo effects”. Journal of Clinical Psychology, 61(7), 855-869.
Lambert (2005) argues that psychotherapy has been shown to be more effective than placebos, and then argues for the dodo bird effect. Placebos vs. bona fide treatments:
A body of literature has now been amassed with predictable results: Patients in so-called placebo control groups typically show greater improvement than patients who are assigned to a wait list or no-treatment control group (e.g., Barker, Funk, & Houston, 1988; Bowers & Clum, 1988; Dush, 1986; Prioleau, Murdock, & Brody, 1983; Sheperd, 1984). Indeed, a variety of placebo treatments that emphasize the usual common factors, such as expectations for change, a prescription for activity, discussion, attention, and warmth, yield substantial effect sizes across a variety of disorders, but fail to benefit patients to the degree that active therapies do…
Two extensive meta-analyses have added substantial evidence about the relationship between therapy and placebo. Lipsey and Wilson (1993) addressed the placebo issue as part of their extensive review of meta-analyses. A subset (n 30) of the meta-analyses reviewed by Lipsey and Wilson (1993) included comparisons of treatment with no-treatment control groups as well as placebo control groups. The results of this review suggest that theoretically based treatments are clearly superior to both no-treatment and placebo treatments. They concluded that “there are quite likely some generalized placebo effects that contribute to the overall effects of psychological treatment, but their magnitude does not seem sufficient to fully account for those overall effects” (pp. 1196–1197).
In another review of the placebo effect, Grissom (1996) examined the relationship of therapy to control, therapy to placebo, placebo to control, and therapy to therapy across 46 meta-analytic reviews. Grissom (1996) used the “probability of superior estimate” (PS) to “estimate the probability that a randomly sampled client from a population given treatment 1 will have an outcome . . . that is superior to that . . . of a randomly sampled client from a population given treatment 2” (Grissom, 1996, p. 973). The overall results “are consistent with the view that the ranking for therapeutic success is generally therapy, placebo, and control (do-nothing or wait)” in that order (Grissom, 1996, p. 979).
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Schnyder, U. (2009). Future perspectives in psychotherapy. European archives of psychiatry and clinical neuroscience, 259(2), 123-128.
Psychotherapy can be considered as one of medicine’s most effective therapeutic approaches. By no means does psychotherapy need to hide away, for instance, from the comparison with drug treatment or surgery. Take, for example, the prescribing of acetylsalicylic acid to prevent myocardial infarction, which has an effect size (treated versus untreated) of 0.07. Medication for rheumatoid arthritis scores 0.61, which is already in the mid-range of effect sizes, whereas aorto-coronary bypass surgery has a comparatively high effect size of 0.80. The effect size of psychotherapy is 0.88, which is within the same order of magnitude, and that is taking all psychotherapeutic approaches together. If the cognitive behavioral therapies are considered separately, their effect size is as high as 1.21
Why is it that, although effective psychotherapeutic interventions are available today for the commonest mental disorders, the majority of patients either receive no professional treatment at all or, if they do make their way into professional hands, the therapy that is provided will often not be one for which there is sufficient empirical support? One reason is that today most psychotherapists are still not adequately trained in empirically supported treatments. Secondly, many psychotherapists do not like working with treatment manuals; in most cases, they have had no experience with using treatment manuals and are afraid that following treatment steps laid down in a manual will constrain them from giving free reign to their creativity. The other side to this is that both patients and health insurance companies are increasingly demanding the use of evidence-based procedures.
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