Practice-Based Psychotherapy Research
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PPRNet Blog: August 2015

Giorgio A. TascaAt the PPRNet conference in November 2012 over 100 psychotherapy clinicians, researchers, and educators were very keen to receive ongoing information about psychotherapy research that is practice-oriented and presented in an easily readable format. And so the PPRNet Blog was born.

About once a month I will review and summarize two or three published psychotherapy research articles. As part of the summary, I will highlight the practice implications of the research.

Because of copyright issues, we cannot post the full text of the articles, but we will provide a link to the abstract on the publisher's web site. I will also post the author's email address. Most authors are very happy to share their work. So if you want a copy of the article send the author an email with a request for a pdf or reprint.

At the bottom of each review you can post a comment, and comment on your colleagues' comments. I will update these as frequently as possible.

If you have ideas for an article to review or a topic you would like to see covered, please send me an email at

Giorgio A. Tasca

blogIs The Particular Therapist Important?

The Great Psychotherapy Debate: Starting in April, 2015 I will review parts of The Great Psychotherapy Debate (Wampold & Imel, 2015) in the PPRNet Blog. This is the second edition of a landmark and sometimes controversial book that surveys the evidence for what makes psychotherapy work. Since this is a book I will not provide the author email. However, you can view parts of the book in Google Books.

Wampold, B.E. & Imel, Z.E. (2015). The great psychotherapy debate: The evidence for what makes psychotherapy work (2nd edition). New York: Routledge.

Some therapists achieve better patient outcomes than others. This seems obvious on the surface and yet few people talk about it, and the research literature seems to downplay or ignore this fact. To illustrate the differing outcomes achieved by therapists, I reviewed a unique study in the September 2013 PPRNet Blog. In that study, 10 cases were randomly selected from 700 therapists (N = 7000 patients), and therapist outcomes were assessed by averaging their patient outcomes. Depending on the presenting problem, as many as 67% of therapists were reliably effective, but as many as 16% were reliably harmful. Clearly therapists differ. Yet psychotherapy research typically treats therapists as if they are uniformly effective. In their chapter, Wampold and Imel review some of the research that estimates the therapist’s effect on outcomes. In other words, what is the impact of the particular therapist on the patient outcomes? Even in studies in which: (a) therapists are selected as experts to provide a specific type of therapy (i.e., CBT, psychodynamic, interpersonal, etc.), (b) therapists are highly trained to be adherent to a manual with repeated supervision, and (c) patients are randomly assigned to treatments, there remains a significant amount of variability in therapist outcomes. Indeed in many studies the therapist effect is as large or larger than the effect of the intervention that is being delivered. In other words, which therapist a patient gets in a treatment study matters just as much or more than what type of therapy they receive. This is also true in medication trials. Better psychiatrists (i.e., those with overall better patient outcomes) who gave a placebo had better patient outcomes than poorer psychiatrists who gave the active medication. A recent large meta analysis found that about 5% of patient outcomes in controlled psychotherapy trials was attributable to the therapist, and the effect is as high as 7% in naturalistic settings. For treatment of PTSD, therapist effects are as high as 12%. On the surface these look like small effects, but in reality they can have a big cumulative impact. Therapists with the best and worst outcomes differ dramatically. For example in one large study, the best performing therapists had a patient response rate of 80% compared to the worst performing therapists who had only 20% of their patients improve. Which therapist would you want a loved one to see?

Practice Implications

Wampold and Imel reported that that therapist effects generally exceed the effects of the specific treatment that is being tested or provided. Some therapists consistently achieve better patient outcomes than others. What are the characteristics and actions of effective therapists? Factors like therapist allegiance to the therapy, empathy, and the ability to form and maintain an alliance with clients appear to differentiate therapists who consistently have good patient outcomes versus those whose patients tend to have poor outcomes.

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blogPsychological Treatments for Post Traumatic Stress Disorder

Bradley, R., Greene, J., Russ, E., Dutra, L., & Westen, D. (2005). A multidimensional meta-analysis of psychotherapy for PTSD. American Journal of Psychiatry, 162, 214–227.

The psychotherapy research literature on treatment of post traumatic stress disorder (PTSD) has focused on cognitive behavioral therapy (CBT, with exposure and/or cognitive restructuring) and eye movement desensitization and reprocessing (EMDR). Exposure therapy involves confronting memories of the trauma or cues related to the traumatic event. Other CBT skills include developing skills for anxiety management or challenging distorted cognitions. In EMDR the patient is asked to develop an image of the traumatic event while tracking a bilateral stimulus. Most studies demonstrate the effectiveness of CBT for PTSD in the short term. However, many studies have excluded patients with comorbid conditions. For example, patients with PTSD often also have significant other symptoms like depression, substance abuse, other anxiety disorders, and personality disorders. In this meta analysis, Bradley and colleagues were interested in documenting the overall efficacy of psychological treatments for PTSD. They also wanted to report on any evidence on the long term efficacy of treatments for PTSD, and on evidence of the effects of excluding patients with comorbid disorders. Bradley and colleagues included randomized controlled trials published between 1980 and 2003 (i.e., 26 studies representing 1,535 patients). Also, they looked at outcomes defined in a few ways: change in symptoms as documented by the effect size, proportion of patients no longer meeting diagnostic criteria for PTSD (but who may have residual symptoms), and proportion whose symptoms improved significantly. Across all treatments, the average pre to post effect size was large (d = 1.43), and comparisons to control conditions were also large (d = .83). The results suggested that psychotherapy produced substantial effects for PTSD. Differences between types of therapy (CBT, CBT with exposure, EMDR) were negligible. Fifty six percent of patients no longer met criteria for PTSD, and 65% showed improved symptoms. At follow ups, 62% no longer met diagnostic criteria for PTSD and 32% were deemed improved, but the number of studies with follow up data were small (k = 10) and so the results could be unreliable. Of those who started treatment, 78.9% completed the therapy. Of those who were assessed, 30% were excluded because of suicide risk, drug or alcohol abuse, or "other serious comorbidity".

Practice Implications

Treatment guidelines from the International Society for Traumatic Stress Studies list a number of effective treatments for PTSD. The evidence for efficacy is strongest at post treatment, and more research is necessary to demonstrate efficacy in the longer term. There is currently little evidence that any one treatment approach is more effective than another, and some researchers are debating whether specific interventions like exposure is necessary to treat PTSD. Bradley and colleagues argue that we need more research on alternative treatments for PTSD and research on patients with multiple symptoms and comorbidities.

View the Psychological Treatments for Post Traumatic Stress Disorder abstract.

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blogEfficacy of Humanistic Psychotherapies

Angus, L., Watson, J.C., Elliott, R., Schneider, K., & Timulak, L. (2015) Humanistic psychotherapy research 1990–2015: From methodological innovation to evidence-supported treatment outcomes and beyond. Psychotherapy Research, 25, 330-347.

In this wide-ranging review, Angus and colleagues provide an overview of humanistic psychotherapy research from 1990-2015. For this blog I will focus on the efficacy research that they review. Humanistic psychotherapy addresses how people can come to know themselves and each other, and to fulfill their aspirations. This type of therapy emphasizes the personal, interpersonal, and contexts within which clients reflect on their relationships with the self, others, and the world. Carl Rogers is probably the best known early proponent of humanistic client centred psychotherapy. Humanistic psychotherapy focuses on a genuinely empathic therapeutic relationship to promote in-therapy client emotional experiencing, emphasizes meaning-making, and is person-centred. One of the questions raised by Angus and colleagues was: are humanistic psychotherapies efficacious. Here they mainly summarize a previous review by Elliot and colleagues (2013). In a meta analysis of 191 studies and over 14,000 clients, humanistic psychotherapies are associated with large pre to post therapy client change (g = .93) which are maintained over early (< 12 months) and late (> 12 months) follow ups. Further, in 31 studies of over 2,000 clients, those who received humanistic therapies show large gains compared to those who receive no treatment (g = .76). In 100 studies of over 6,000 clients, humanistic therapies had equivalent outcomes to other therapies (g = .01), including CBT (22 studies, g = -.06). Humanistic therapy was most effective for interpersonal/relational trauma, and depression (for which it is considered an evidence supported treatment). There is also good evidence for the efficacy of humanistic therapy for psychotic conditions. However, humanistic therapies may be less effective than CBT for anxiety problems.

Practice Implications

Humanistic psychotherapy that focuses on a genuinely empathic therapeutic relationship that emphasizes client emotional experiencing and meaning-making is efficacious for a number of mental health problems. Rogers argued that non-judgemental acceptance, warmth, and congruence were necessary for good client outcomes, and an accumulating body of research is supporting these early propositions. The evidence for the importance of therapist empathy to improve client outcomes is particularly compelling.

View the Efficacy of Humanistic Psychotherapies abstract.

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