Helping the whole person

: the development of the Pluralistic Therapy Integrity Scale

Abstract

The aim of this thesis is to develop a treatment integrity scale for pluralistic therapy by combining the literature on pluralistic therapy and treatment integrity testing with data collected on the experiences of pluralistic therapists and developers. Pluralistic therapy is based on a philosophy which posits that many different things can help clients at different times. Perhaps as a result, there is no defining set of principles which one would expect to observe in a pluralistic therapy session. Treatment integrity testing within psychotherapy is required to ensure that the therapy being tested is being delivered as intended. To test pluralistic therapy, it is first necessary to define it. Defining the underlying principles then allows for a flexible treatment integrity scale to be developed. Firstly, pluralistic students and practitioners were asked to rate the importance of different items on the original pluralistic therapy treatment integrity scale (G-APP, McLeod & Cooper, 2012) in Study 1 and an adapted version in Study 2. Most participants agreed on a number of aspects (such as encouraging client involvement and adapting therapy to fit preferences) although there were important areas of disagreement (such as the use of tasks and methods). Study 3 analysed secondary data of frequency-of-use ratings to compare skills and techniques used by pluralistic and integrative therapists. This revealed significant differences between pluralistic and integrative therapists in the frequency of using even those skills identified as contentious in Studies 1 and 2. In Study 4, semi-structured interviews with pluralistic practitioners concerning the key areas of dissensus discovered in Studies 1-3 showed that there was a consensus over the main principles of pluralistic practice such as the importance of client agency. However, it was also discovered that the theory’s relatability to the therapist or the client drove decisions around which part of pluralistic therapy to use, meaning that the suggested levels of collaboration and transparency do not always occur in pluralistic therapy. In the fifth and final study, the findings from the previous studies were put to the original developers of the pluralistic framework in interviews. This uncovered similar levels of dissensus as seen in Studies 1-4, indicating that the original developers’ beliefs about some key aspects of pluralistic therapy had changed over the past decade. The thesis culminates in the development of the Pluralistic Therapy Integrity Scale which combines the findings and the literature from the previous five chapters. The scale is based on the pluralistic principles which were uncovered in Studies 1-5, which are underpinned by collaboration between therapist and client. The thesis ends with a general discussion about the main themes uncovered and its contribution to the field of research on pluralistic therapy and treatment integrity testing.

Date of Award	5 Nov 2025
Original language	English
Awarding Institution	Abertay University
Supervisor	Sheila Cunningham (Supervisor), Mhairi Thurston (Supervisor) & Kate Smith (Supervisor)