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PPRNet Blog: November 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

blogThe Logic of Placebos in Medicine and Psychotherapy

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.

A couple of decades ago Martin Seligman famously said: "Whenever you hear someone demanding a double-blind study of psychotherapy, hold on to your wallet." In this chapter, Wampold and Imel continue their examination of the Medical Model versus the Contextual Model for psychotherapy by discussing the viability of double-blind placebo control designs in psychotherapy. This topic sounds a little esoteric, but it’s not – this issue reaches into the very core of the definition of psychotherapy. A placebo-controlled trial in medicine often involves comparing a medication that contains an active biochemical ingredient versus a "sugar pill" that is exactly like the medication but without the active biochemical ingredient. Key to the placebo controlled design is that the health care provider, the patient, nor the researcher/evaluator knows which patient received which pill (i.e., the classic "double-blind" design). However, double-blinding is impossible in psychotherapy – the therapist must know what they are providing, which means that they know which treatment is expected to be effective, and which treatment is favoured by the researchers. Further, the researchers know which patients are getting which intervention of study condition. This affects a critical aspect of psychotherapy, that is, the therapist’s ability to provide a good rationale for the disorder and for the efficacious actions of the therapy. Additionally, patients are often aware that they are getting a pseudo-treatment in the placebo, and so their expectation of outcomes is also lowered (actually, this is often true in medical trials as well as most medications have side effects, and the absence of a side effect signals to the patient and the researcher that the patient is receiving the placebo). Wampold and Imel argue that common factors like emotional arousal, an acceptable explanation of the disorder, an understanding and empathic therapist, a structure to the treatment, and therapist and client expectations and hope are integral to the effectiveness of psychological therapies. They further argue that these are the very factors that medical trials try to control with a double-blind placebo controlled trial. Nonetheless placebo-like controls have been tried in psychotherapy to test the active or specific ingredients of a therapy – that is, to isolate the effects of active ingredients from the relationship context of the therapy. Placebo-like controls in psychotherapy have been called: minimal treatment, supportive counselling, non-directive counselling, etc. However, as mentioned, these placebo control conditions often contain elements that are integral to the effectiveness of psychotherapy, like: emotional arousal, an empathic therapist, and client expectations. And so not surprisingly, after reviewing meta-analyses of placebo-like conditions in psychotherapy research, Wampold and Imel conclude that when the studies are well constructed, these placebo-like conditions perform nearly as well as evidence-based treatments.

Practice Implications

What is the take home message for the clinician of this seemingly esoteric topic about research design? Although the placebo-controlled double-blind randomized design is the gold standard in medical research, this design is not possible or even logical for psychotherapy. The relationship, therapist factors, expectations, and contextual factors that one tries to control in a placebo-controlled trial are some of the very ingredients that are active in psychotherapy. The technical and specific ingredients of psychotherapies (e.g., transference interpretations, cognitive restructuring, two-chair techniques, etc.) are also part of the mix; but in the end, one cannot separate contextual relationship factors from techniques when it comes to providing psychotherapy.

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blogDoes Frequency of Sessions Affect Patient Outcomes?

Erekson, D.M., Lambert, M.J., & Egget, D.L. (2015). The relationship between session frequency and psychotherapy outcome in a naturalistic setting. Journal of Consulting and Clinical Psychology,

The dose-response model of psychotherapy suggests that a single session is like a "dose" of therapy, and that each session adds to a cumulative response by the client. For example, research indicates that between 13 and 18 sessions are required for 50% of patients to improve significantly, but with diminishing returns for clients after 18 sessions. In this very large study in a naturalistic setting, Erekson and colleagues studied the question of the effects of the "dose" or quantity of therapy a little differently. What if the spacing or frequency of sessions rather than the total number of sessions was important to patient outcomes? That is, if psychotherapy reinforces adaptive behaviors, then less learning might occur if time between sessions increases. With greater time between sessions clients may miss timely support from a therapist, and the therapeutic alliance may not be as solid. Erekson examined the impact of session frequency in a very large sample of university students (N = 21,488) seen by therapists (N = 303) for individual therapy lasting about 50 minutes per session. Clients typically received between 6 and 21 weeks of therapy. The data were collected at a counselling center over a 17-year period. Therapist orientations included CBT, psychodynamic, existential, and integrative. Patient outcomes were measured after each session with a reliable measure that allows one to evaluate if a client recovered from symptoms, reliably improved but did not recover, or reliably deteriorated. The authors found that compared to less frequent sessions (approximately every 2 weeks), more frequent sessions (approximately weekly) was associated with faster improvement and faster recovery. The statistical models predicted that 50% of individuals being seen weekly would reliably improve in 8 sessions, whereas 50% those seen every 2 weeks would reliably improve in 12 sessions. That is, clients seen every two weeks required 50% more sessions to achieve the same level of improvement as clients seen every week.

Practice Implications

Clients that are seen weekly may have a better therapeutic experience and develop a better therapeutic alliance with their therapists, which may in turn result in faster improvements. More frequent meetings may suggest to clients that their needs are important to the therapist. Institutions may have the opinion that lower session frequency is a way of saving resources, but in the end patients seen less frequently may require more therapy to achieve outcomes at the same rate as patients seen more frequently. Higher frequency of sessions may increase the efficiency of the psychotherapy and possibly reduce the amount of resources invested by the institution to improve patient mental health outcomes.

View a copy of the Does Frequency of Sessions Affect Patient Outcomes? article.

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blogDoes Duration of Therapy Affect Patient Outcomes?

Stiles, W.B., Barkham, M., & Wheeler, S. (2015). Duration of psychological therapy: Relation to recover and improvement rates in UK routine practice. British Journal of Psychiatry, 207, 115-122.

In this very large study from the UK National Health Service (NHS), Stiles and colleagues assessed whether more therapy is better. That is, do people continue to get better with more sessions or do patients reach a certain level of improvement and terminate therapy regardless of number of sessions. The "dose-effect model" of psychotherapy suggests that patients continue to improve with more sessions, although the rate of improvement slows down after 18 sessions. However, large naturalistic studies from the UK health system show that patients have similar rates of recovery regardless of the number of sessions they attend (i.e., up to 20 sessions). These findings suggest that patient improvement may follow a good-enough or "responsive regulation model" of improvement, in which patients responsively regulate the number of sessions that they need. This could have implications for policies regarding how many sessions are prescribed to patients. In this study, Stiles and colleagues drew data from the NHS data base of over 26,000 adult patients who were seen by 1,450 therapists. These were patients who provided enough reliable outcome data, who attended 40 or fewer sessions, and who had a planned ending. Many patients had multiple problems including anxiety, depression, bereavement, and trauma and abuse. Patients who were selected for the study had initial symptom scores in the clinical range. The most common therapy approaches included integrative, psychodynamic, CBT, and supportive. Patient "recovery" was defined as no longer scoring in the clinical range at the end of therapy. Patient "improvement" was defined as a reliable drop in symptom scores on a psychometric measure. Patients received an average of 8.3 sessions, 60% recovered, and an additional 19% improved but did not recover. Rates of reliable improvement were negatively correlated (r = -.58) with number of sessions, and the effect was large. That is, patients who stayed in therapy longer had lower rates of recovery. These patients were more symptomatic at the outset.

Practice Implications

The results of this very large naturalistic study suggest that therapists and clients should regularly monitor improvement and adjust the treatment duration based on whether clients improve to a satisfactory level. The authors refer to this as "responsive regulation" of treatment duration. In practice, this means that therapists and clients end treatment when patients have improved to a "good-enough" level, which is likely balanced against costs and alternatives. These findings should encourage therapists and agencies to shift their attention away from prescribing a pre-specified length of treatment at the beginning of therapy towards evaluating on an ongoing basis what constitutes good-enough gains for each client.

View a copy of the Does Duration of Therapy Affect Patient Outcomes? abstract.

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