Introduction to Special Issue

Shigeru Iwakabe, PhD and Diana Fosha, PhD

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This special issue of Transformance Journal marks a flourishing state that AEDP (Fosha, 2022) and AEDP Practioner Research Program (PRN) research have achieved. The five articles are the result of the crystallization of research-practice integration. We believe this special issue will contribute not only to the development of AEDP research and practice but also to psychotherapy research more widely as a prime example of a mixed methods study that combines the rigour of outcome studies and the clinical depth and richness of case studies (Fishman et al., 2017). This introduction will present a brief overview of AEDP PRN Research.

History and purpose of the AEDP Practioner-Research Network Study

AEDP Practitioner-Research Network Study was launched in 2016. In the era of evidence-based practice, it was an imperative that we demonstrate the effectiveness of AEDP in an empirically rigorous and systematic way. However, this was not our primary or solo goal. Our research project aims to build the research infrastructure within the AEDP Community and seamlessly integrate it into the practice of AEDP so that the research eventually becomes part of AEDP’s everyday practice. We also aim to develop research methods that can minutely describe the emergent change phenomena in AEDP so that we can identify more specifically principles of AEDP’s change process and therapists’ innovative and masterful moment-to-moment interventions that have not fully been articulated or delineated in the formal theory of AEDP (Fosha, 2000, 2021). We know through observing numerous hours of videorecorded sessions that AEDP can help patients have moments of unparalleled transformation. Such moments of profound transformation deserve not only to be appreciated by clinicians’ discerning eyes but to be examined fastidiously so that their underlying mechanisms are better understood and their principles teased out. Empirical research provides AEDP practitioners with firm objective support for their effectiveness, as well as communicates to the larger psychotherapy community the important contributions of AEDP.

Designing the AEDP PRN study from a Practice Oriented Research paradigm.

To build a research program that truly supports the practice of AEDP, we needed to design our research program based on the worldview of AEDP (Fosha, 2021) so that so that the research will be clinically meaningful to AEDP practitioners. AEDP therapists already practice with rigor and precision as they repeatedly watch their sessions, analysing the moment-to-moment dyadic processes in their supervision, training, and everyday practice. Our intention was to build on this tradition, enhance it and make the fullest use of it.

For the last twenty years, there has been a proliferation of randomized clinical trials that focused on building ‘rigorous’ and ‘unbiased’ evidence for the efficacy of psychotherapy. Randomized Clinical Trials (RCTs) compare a particular treatment model against a control group in a very controlled experimental setting1. Although findings from RCTs are considered as the most reliable and valid evidence from a single study, many researchers and practitioners have questioned the clinical usefulness of the findings. Deaton and Cartwright (2018) recently provided a persuasive criticism of the methodology. One of the serious consequences of RCTs is the enlargement of the gap between research and practice. RCTs do not simply reflect the reality of clinical practice. Many psychotherapists, therefore, do not rely on findings of these studies in their clinical practice because they do not provide ‘clinically useful information from which they can improve their practice.

Prominent psychotherapy researchers have been exploring alternatives to RCTs. One of the potent approaches is Practice-Oriented Research (POR) which encourages mutual collaboration and respect between researchers and clinicians in designing and conducting research so that what comes out from research is clinically informative and empirically rigorous (Castonguay et al., 2013). Instead of adjusting treatment parameters to fit into a uniform framework of RCTs, POR seeks to find innovative ways of conducting research while maintaining the practice-as-usual in clinical settings (Yoon et al., 2016).

The AEDP PRN Study is built on such tradition and seeks to extend its principles so that the theory and practice of AEDP is not only reflected in the way that each study is conducted, but also has at its goal the seamless integration of research and practice. One of our goals is that both clinicians and researchers benefit when there is a positive feedback loop between research and practice. That is, researchers and clinicians can begin to positively inform one another, such that the AEDP therapist becomes a researcher within a clinician, and the AEDP researcher becomes a clinician within a researcher.

The initial phase of AEDP PRN Study

The AEDP PRN study has already produced a substantial empirical attestation for the effectiveness of AEDP and is currently stimulating the field of psychotherapy research in general in a uniquely AEDP fashion. The first outcome study (Iwakabe et al., 2020) that examined the post-treatment outcome of 63 dyads who went through a 16-session individual treatment showed that AEDP was effective in improving a wide variety of psychological functioning: reducing psychological symptoms such as depression, improving positive psychological functioning such as self-compassion and flourishing, improving emotional and cognitive functioning, as well as addressing interpersonal problems. In another study, the long-term effectiveness at both 6-and 12-month intervals was tested (Iwakabe et al., 2022). Results showed that patients maintained their gains over 12-months on all measures. We demonstrated the effectiveness of AEDP by examining effect size, clinical significance, and the proportion of patients that moved into functional range. Since these studies were conducted without control groups, we adopted these multiple stringent criteria for evaluating the treatment effect.

The second phase of the AEDP PRN research

With this strong evidence indicating that AEDP works, the research has moved to the second phase. In the first phase, our main goal was to establish the effectiveness of AEDP in relation to the effectiveness of other major approaches whose effectiveness has been established. For that goal, we selected outcome and process scales commonly used in outcome research studies for comparison. Now that the effectiveness of AEDP had been established, we wanted to examine quintessential AEDP contributions to positive process and outcome. We developed scales that tap into theoretical constructs that are unique to AEDP such as undoing aloneness, transformational affects, etc.

In Phase II, we have developed three new measurement scales. The first is the Moments of Flourishing Experience Scale (MFES), which measures emergent and more transient experiential manifestations of flourishing potential. The MFES can be used for academic psychology and in clinical research for both outcome and process measures. Another new scale is called AEDP 9+1 Change Process Scale. This scale, completed by the therapist at the end of each session, examines specific interventions that the therapist utilized in the session. This scale is not only a research scale but also a training tool that can be used for therapists to learn a wide range of

AEDP interventions. Finally, Nate Thoma and I developed the Transformational Process Scale (Thoma & Iwakabe, 2019), which is an observer scale completed by raters who categorize a one minute segment of the therapy session into one of four states of transformation. We believe the development of these three scales, will allow a more refined understanding of change processes and mechanisms of AEDP.

One of our ongoing research studies is on healing from the get-go. Healing from the get-go is an important therapeutic adage in AEDP. Our goal was to provide an empirical basis for this concept. My doctoral student, Marina Yabuki-DiCorcia and other members of the research team watched and rated videos of first sessions of patient’s emotional processes using the Transformational Process Scale. We found that in the most productive first sessions – as judged from the Working Alliance Inventory (WAI) and the Session Rating Scale rated by patients – there was a higher occurrence of States 2, 3, and 4 than in less productive first sessions. It appears that in these highly productive sessions, patients successfully processed not only their core affects but also transformational affects that occurred after processing core affects (Yabui- DiCorcia et al., 2023). We are in the process of looking more closely into these first sessions to reveal what makes healing from the get-go possible. The first session traditionally has been restricted to informational gathering and rapport building. However, our research shows that it is possible to bring about a corrective emotional experience in the very first session, expanding the therapeutic potentials of early therapy sessions. This study, therefore, has substantial implications over and beyond the practice of AEDP.

We are also focusing on the therapeutic relationship and other common factors such therapist factors and patient pretreatment expectations that are operative in AEDP. As our focus shifts toward aspects of AEDP that are unique to our model, we must ensure that we do not lose sight of how some of the common factors contribute to process and outcome of AEDP. It is also important to examine how these common factors manifest in AEDP and also interact with some variables that are closely related to AEDP.

One such study we conducted was on the relationship between the working alliance and positive emotions. We tested whether the working alliance contributes to the patient’s experience of positive emotions, or the converse, whether the patient’s experience of positive emotions contributes to the building of the working alliance (Notsu et al., 2022). The study used a statistical “lag sequential” model which takes into account the complex interactions between the two variables. The result showed that positive emotions contributed to building the alliance from the beginning of therapy but that the alliance did not contribute to experience of positive emotions.

In another study (Nakamura et al., 2023) we examined the relationship between the trajectory of the working alliance and improvement in depression using a growth mixture model that allows identifying the patterns of the working alliance over time and relate them to the proportion of patients who improved on outcome variable, in this case, depression as measured by Beck Depression Inventory. We found three patterns of the working alliance development. One pattern is a consistently high working alliance with starts out at a high WAI score from the beginning with significant increase over time. This pattern of development was seen 62 dyads out of a total of 100 dyads and 73.3% of them achieved clinically significant change. A second pattern of the working alliance development involved a noticeable linear tendency starting from a moderately high alliance to a very high alliance. Twenty-six dyads had this pattern and 84.2% of them achieved clinically significant change. Finally, there was an undeveloped pattern characterized by the fluctuating but not incremental pattern of the alliance. There were 12 dyads that fit this pattern and only 34.5% of them achieved clinically significant change on the depression inventory. The study shows that the alliance is important for AEDP to be successful, and when the alliance does not increase over time, therapists need to pay attention to it and discuss it with their patients.

Phase II is already progressing. Our preliminary analyses confirm the effectiveness from Phase I for both post-treatment outcome and long-term follow-up for over 100 dyads. We have a total of 43 dyads in Phase 2. This large sample will enable us to test many hypotheses that examine AEDP’s theoretical principles and ideas in a rigorous manner.

This special issue

This special issue has a series of case studies in the AEDP PRN Research. Five therapists present their research cases and discuss their own experience of being the research therapist. Fishman et al. (2017) proposed a new research paradigm called mixed methods design which presents case studies out of an outcome study. Case studies are a part of outcome study so that they have objective measurement of process and outcome. They are based on systematic data that go well beyond the therapist’s process notes which reflect only what the therapist deemed important: Sessions in the research project are always recorded and available for further review and scrutiny; both the therapist and the patient complete post-session questionnaires, and finally follow-up interviews with the patients are conducted at various intervals. In short, the outcome study tells us whether the overall treatment is effective; but systematic case studies tell us how they were effective by detailing the process of change.

Here we have articles written by five major contributors to the research. Their view of research therapy provides an important view of how some of the research parameters are affecting their practice. As Tunnell (this issue) puts it: Producing transformational change in 16 sessions is “quite a task, but, in fact, a major advantage for therapists who work within the 16-session paradigm is that they are far more likely to stay on course to accomplish the overarching goal to transform “suffering into flourishing, ever mindful that time is pressing on.” Silvan (this issue), similarly comments on the importance of 16-session research therapists’ “requirement to rigorously adhere to AEDP methodology.” Harrison (this issue) instructs that the time limit need not be a limitation, rather, “instead, the time limit adds to the treatment and has much to offer: It helps accelerate the therapy and the healing.”

Participation in our research was sometimes challenging for our therapists, yet useful in guiding their treatment and keeping it on track. McDonnell (this issue) describes the benefit of adhering to the imperative that AEDP therapists establish conditions for secure attachment “from the get- go” in a case involving POC-White dynamics. Woods (this issue) reports on the patient’s experience of a time-limited treatment: “Many patients experience the time-frame as confidence in their capacity to change, grow and accomplish much in a brief time, like the young adult who feels both the sadness and anxiety of a known transition, yet also looks forward to leaving home.” These statements attest to the fact that AEDP therapists are witnessing the synergetic effect of practice-research integration.

Such systematic case studies demonstrate how a 16-session treatment is conducted and how successful treatment may be different and similar across cases and across therapists. These therapists have now become quasi-researchers themselves as they examine the process of therapy along with empirical data, developing for us more robust case studies. In short, the AEDP PRN study is progressing as a PRN study with AEDP practitioners becoming researchers themselves bringing their clinical insights into the research and utilizing research tools and data to inform their clinical work.

We would like to thank these and other AEDP therapists who sign up for this research, and AEDP faculty members for supporting this project. Without their unlimited and generous support, a project of this scale cannot be possible. We would also like to thank patients for their participation. We hope that readers of these articles will be interested in learning more about the project and in joining the research project themselves. Finally, I would like to thank our research committee members for their invaluable contributions: Jennifer Edlin, Liza Greville, Richard Harrison, Kaori Nakamura, Andrew Joseph as well as Sarah Nunnink, Nate Thoma, Nuno Conceicao, and Heather Gretton.

Shigeru Iwakabe, Ph.D. is Director of AEDP Research and Co-Chair of the AEDP Research Committee. He is professor of psychology at the Department of Psychology, Ritsumeikan University, Ibaraki, Japan. He is the General Vice President for The Society for Psychotherapy Research. Address correspondence to:

Diana Fosha, Ph.D. is the developer of AEDPTM psychotherapy and Founder and Director of the AEDP Institute. Address correspondence to: Diana Fosha, Ph.D. 225 Broadway, Suite 3400, New York, New York 10007. Email:

1Randomized clinical trials require: (a) patients or participants are randomly selected from a pool of patients who usually present a single psychological disorder and then randomly assigned to either treatment or control group; (b) therapists use a treatment manual for their intervention and their adherence is monitored; and (c) outcome is assessed by those clinicians who are unaware of the treatment condition under which a particular patient was in. These experimental controls are for increasing internal validity of a study to establish a causal relationship between the treatment and outcome.


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