Practice-Based Psychotherapy Research
To Improve The Wellbeing Of Our Community

PPRNet Blog: August 2013

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

blogHow Much Psychotherapy Is Necessary?

Handbook of Psychotherapy and Behavior Change

Starting in March 2013 I will review one chapter a month in the Handbook of Psychotherapy and Behavior Change in addition to reviewing psychotherapy research articles. Book chapters have more restrictive copy right rules than journal articles, so I will not provide author email addresses. If you are interested, the Handbook table of content can be viewed on Amazon.

How Much Psychotherapy Is Necessary?

Lambert, M.J. (2013). The efficacy and effectiveness of psychotherapy. In M.J. Lambert (Ed.) Bergin and Garfield's handbook of psychotherapy and behaviour change (6th ed.), pp. 169-218. Hoboken, N.J.: Wiley.

An important issue for patients, therapists, and agencies is the optimal dosage of psychotherapy that is necessary to reduce impairment and improve life functioning. In this part of the Handbook chapter on Efficacy and Effectiveness of Psychotherapy, Lambert tackles the issue of the psychotherapy dose-response relationship by reviewing the existing literature. That literature tends to focus on naturalistic national (U.S.) samples of patients (often N > 6,000) receiving routine care in Health Maintenance Organizations, Employee Assistance Programs, and Community Mental Health Clinics. Outcomes tend to be assessed by patient self report, and can include symptoms, character traits, quality of life, and interpersonal functioning, among others. Lambert defines “improved” patients as those who reliably changed but still are within the dysfunctional range on a measure, and he defines “recovered” patients as those who both reliably improved and were no longer in the dysfunctional range. He concluded that on average 50% of patients who begin treatment in the dysfunctional range achieve recovery following 21 sessions of psychotherapy. On the flip side, half of patients do not achieve recovery after 21 sessions. Almost 50 sessions are necessary for 75% of patients to recover. In other words, there is a rapid rate of recovery in which half of patients recover after 21 sessions, but then the rate of recovery slows down so that it takes up to 50 sessions for an additional 25% of patients to recover. The rates of recovery also differ depending on what is measured. Symptoms (depression, anxiety, etc.) tend to recover more quickly than characterological or interpersonal problems. Further, some patients experience sudden symptom gains in therapy that are long lasting. Between 17% and 50% of patients experience the majority of their symptom improvements within 7 sessions, and these early changes accounted for 50% of total symptom gains in therapy.

Practice Implications

The question of how much therapy is enough is important for practical and theoretical reasons. Research on this topic can help patients, therapists, and agencies make decisions about treatment planning. Research suggests that a sizeable proportion of patients (50%) reliably improve after 7 sessions and a similar percentage recover after 21 sessions. However, limiting treatment to less than 20 sessions will mean that about half of patients will not achieve a substantial benefit from therapy. Session limits need to be assessed carefully depending on how the patient is doing and what outcomes are important or valued. Agencies or clinicians that firmly set limits on the number of psychotherapy sessions that are too low will have the majority of their patients showing some improvement but not recovering.

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blogDoes Focus on Retelling Trauma Increase Drop-out From Treatments For Posttraumatic Stress Disorder (PTSD)

Imel, Z. E., Laska, K., Jakupcak, M., & Simpson, T. L. (2013). Meta-analysis of dropout in treatments for posttraumatic stress disorder. Journal of Consulting and Clinical Psychology, 81, 394–404.

There are now a number of psychotherapies that the Society of Clinical Psychology list as effective psychotherapies available for posttraumatic stress disorder (PTSD). Approaches include prolonged exposure (PE), and cognitive processing therapy (CPT) among others (view PE and CPT examples). Therapies for PTSD also vary in how much they focus on retelling the trauma. Some treatments like trauma-focused CBT place a higher level of focus on retelling the trauma event, whereas Present Centred Therapy (PCT), which was originally conceived as a control condition, largely avoids the trauma. Patients may begin a treatment and find some aspect of it distressing resulting in discontinuation. There is ongoing debate regarding the belief that exposure-based treatments, which require the patient to retell traumatic events in detail to his or her therapist, are especially unacceptable or poorly tolerated by patients. Drop out rate is a common metric used to assess tolerability of a treatment. In the April 2013 blog I reported on a meta analysis that found that the average drop out rate in randomized controlled trials of adult psychotherapy was 19.7%. However drop out rates for PTSD in the community can be as high as 56%. Imel and colleagues conducted a meta analysis of drop out rates in randomized controlled trials of treatments for PTSD. They also assessed if drop out rates differed by the amount the therapy focused on retelling the trauma. In the meta analysis, 42 studies were included representing 1,850 patients; 17 of the studies directly compared two or more treatments. The aggregated drop out rates across all studies was 18.28%, which is not different from the rate in randomized trials of adult psychotherapy in general, but is much lower than reported in regular clinical practice. Group treatment was associated with a 12% increase in drop outs compared to individual treatment. In general, an increase in trauma focus was not associated with greater drop out rates. However, when trauma focused treatments were directly compared to PCT (a trauma avoidant intervention) in the same study, trauma-specific treatments were associated with a twofold increase in the odds of dropping out.

Practice Implications

Many have been concerned that exposure-based therapies can lead to symptom exacerbation and result in dropout. The findings of Imel and colleagues’ meta analysis suggest that dropout rates are not significantly different among active treatments. However, PCT may be an exception to this general pattern of no differences among active treatments. Perhaps PCT should be considered a first line treatment for those who do not prefer a trauma focused treatment. In addition, providing treatment for PTSD in groups was associated with greater drop out rates possibly due to shame related to public disclosure of the trauma. The authors suggest mimicking research trial procedures in community practice in order to reduce drop out rates, such as: providing therapist training, support, and supervision; careful patient screening; regular assessment of patient progress; and ongoing contact with assistants that may promote session attendance.

View the Does Focus on Retelling Trauma Increase Drop-out From Treatments For Posttraumatic Stress Disorder (PTSD) study abstract.
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We have an active group therapy program going on 7 years old as part of an outpatient Mental Health program at Ross Memorial Hospital in Lindsay Ontario. We have about a 30% drop out rate at the point therapy shifts from talking about managing symptoms, which has a nearly zero drop out rate, to the 30% mark as the focus moves to responsibility for identifying what is needed to move on toward a desired life. We do not allow detailed discussion about the traumas themselves in the group setting, but require people moving into the last phase to have a one to one therapist as well to whom they may, if they desire, tell details. We require it for the purpose of safety as the shift in focus can be especially triggering for poor coping skills such as self-injury, suicidality, substance abuse, return to gambling etc. I cannot prove this without a controlled study of course, but my observation is that the people who drop out fear the loss of identity as a 'hurt person' more than they (at that moment) desire to move away from that into an unknown even if more positive space.

Karla Forgaard-Pullen MSW RSW


Hello Karla,

Thank you for your comments and for sharing your experiences with your treatment of PTSD.

Your drop out rates are better than in community practice in general (50%) but higher than in randomized controlled trials (RCTs) (19%). However, RCTs are selective about participants and have other aspects to them that do not directly parallel community practice. It also seems that your practice is consistent with Imel and colleagues' findings about negative impact of discussing the trauma in groups. Your notion that drop out in the second phase of your program is caused by losing identity as a "hurt person" is very interesting. Have you thought of ongoing outcome monitoring and assessing concepts like hopelessness and self efficacy so that you can see exactly what occurs at the point of transition? This may lead to alterations to reduce drop outs.



I will think about this carefully. In concert with the article citing a need for 20 or more sessions to effectively reach recovery, I can certainly vouch for the fact that recovery is not likely to happen in a shorter period of treatment...maybe we should share that with our clients to encourage them to complete. The whole program is approximately 28 weeks, but parts can be repeated if we and the client feel it is warranted. Thank you for this bit of problem solving.



Great. In the coming months I will review research on ongoing progress monitoring.


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blogHelpful and Hindering Events in Psychotherapy

Castonguay, L.G., Boswell, J.F., Zack, S., Baker, S., Boutselis, M., Chiswick, N., Damer, D., Hemmelstein, N., Jackson, J., Morford, M.,  Ragusea, S.,  Roper, G., Spayd, C., Weiszer, T., Borkovec, T.D., & Grosse Holtforth,, M. (2010). Helpful and hindering events in psychotherapy: A practice research network study. Psychotherapy: Theory, Research, Practice, and Training, 47, 327-344.

There are many reasons why I like this paper, and one reason is that it is a psychotherapy practice research network study (most of the co-authors are independent practice clinicians). This group of clinicians and researchers met on a number of occasions to define the research questions, including: “what do psychotherapists and clients find most and least helpful in a psychotherapy session?”; and “do psychotherapists and clients agree on what was most and least helpful?” The clinicians and researchers also discussed and agreed on the method for collecting and analysing the data. Thirteen independent practice clinicians participated (6 CBT, 4 psychodynamic, and 3 experimental/humanistic). For a period of 18 months, all new clients were invited to participate so that 121 clients with a variety of disorders enrolled in the study. Clients and therapists filled out (on an index card) parts of the Helpful Aspects of Therapy (HAT) measure, which asked them to report, describe, and rate particularly helpful and hindering events from the session they had just completed. For example clients and therapists were asked: “Did anything particularly helpful happen during this session?”; and “Did anything happen during this session which might have been hindering?” When participants answered “Yes” to either of these questions, they were asked to briefly describe the event(s), and then rate them on a scale from 1 to 4 for level of helpfulness or level of hindrance. Both clients and therapists did so at the end of every therapy session. Close to 1500 therapeutic events were recorded by the clients and therapists. The events were then coded and categorized according to type of event by independent raters using an established coding system. Clients rated self-awareness, problem clarification, and problem solution as the most helpful type of events, although self-awareness was significantly the most identified of all helpful events by clients. Therapists rated self-awareness, alliance strengthening, and problem clarification as the most helpful type of events. Therapists identified self-awareness and alliance strengthening significantly more often than any other helpful events. Hindering events were identified much less frequently by clients and therapists. Client identified poor fit (e.g., therapist tried something that didn’t fit the client’s experience) as the most frequent hindering event category. Therapists identified therapist omissions (i.e., failure to provide support or an intervention) as the most frequent hindering event category. Overall, with the exception of self-awareness, therapists and clients did not agree on what were the most helpful or hindering events in therapy.

Practice Implications

Results regarding self awareness indicate that providing clients with opportunities to achieve a clearer sense of their experience (e.g., emotions, behaviors, and perceptions of self) is frequently reported as beneficial by both clients and therapists. The events that therapists most frequently reported as detrimental were those in which they failed to be attuned to their clients’ needs. This may reflect therapists’ concerns with potential alliance ruptures. The overall lack of agreement between therapists and clients on helpful and hindering events raises the question about whether therapists are not aware enough of clients’ experiences, or whether clients are not knowledgeable about what is in fact therapeutic. Perhaps client and therapist ratings of events represent complementary perspectives on what works or does not work in psychotherapy. Regarding participating in research, these independent practice therapists reported that the procedure of writing down helpful and harmful events and reading what their clients wrote after each session had a positive impact on their practice. That is, the process of data collection became immediately relevant to their clinical work.

View Helpful and Hindering Events in Psychotherapy article abstract.

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