Intersession experiences and internalized representations of psychotherapy: A scoping review.

Introduction: Between-session processes outside the therapy room and beyond the direct interaction between a therapist and client can play an important role in the psychotherapeutic process and outcome. These processes are called intersession experiences and can be seen as internalized mental representations of therapy and/or therapists. Due to the COVID-19 pandemic, different digital forms of treatment have successfully been implemented and could be relevant even after the end of the COVID-19 pandemic. Therefore, patients' internalized mental representations may become highly relevant in the future.

Rationale: The aim of this study was to conceptually delineate the current state of research on internalized mental representations of therapy or therapists in the period between sessions and to provide an overview of the evidence. In addition, we aimed to identify research gaps to provide a baseline for further research.

Methods: For this purpose, we conducted a scoping review to obtain a comprehensive overview of the evidence and to identify the relevant research gaps. We searched PsycArticles, Medline, PsycINFO, and PSYNDEX for publications on internalized mental representations.

Results: The final sample comprised 30 publications published from 1989 to 2021. Based on the individual study results, it can be assumed that intersession experiences are of central importance for psychotherapeutic treatment. However, the scoping review showed that there was a large gap in knowledge in the research of intersession experiences. All previous research was barely comparable, and therefore, a generalized statement is not possible.

Conclusion: Future research should provide sufficient information about relevant aspects, such as the setting, therapists, and patients, as these factors are likely to have a significant impact on the outcome. Furthermore, better measurements for the assessment of these processes should be developed.