Change Process in Prolonged Exposure Therapy for PTSD - An Account of Two Cases

Background: A diagnosis of Post-Traumatic Stress Disorder (PTSD) is given to an individual, who develops ongoing distress for over one month, following a traumatic event, comprised of four symptom clusters: Intrusion, avoidance, negative alterations in cognition and mood, and alterations in arousal and reactivity (American Psychiatric Association, 2013). A first-line PTSD treatment, among the most highly recommended, is Prolonged Exposure Therapy )American Psychiatric Association, 2019; Cusack et al., 2016). This therapy focuses on Imaginal exposure to the traumatic event and in vivo exposure to situations that were avoided. Yet approximately one third of patients do not experience improved symptoms and even choose to drop out of treatment due to the severe anxiety that accompanies the exposure to memories of the traumatic event (Foa et al., 2007).

The current study aims to fill information gaps regarding the mechanisms of change, their influence on desired results and challenges to reaching them, including early dropout. Thus, it uses the Assimilation Model to observe how a problematic experience changes across therapeutic sessions (Honos-Webb & Stiles, 1998; Stiles, 2001; Stiles et al., 1990). The Assimilation model suggests that therapeutic change can be achieved through a gradual process of assimilation of problematic experiences. The regular self is conceived of a community of dominant internal voices that represent life experiences. A problematic experience, such as a traumatic event, leaves traces which become problematic voices that threaten the regular self. Thus, the self attempts to avoid the problematic voice, and the effort creates emotional pain. Assimilation happens through internal dialogue between the regular self and the problematic experience. According to the model, successful therapy includes a predictable developmental pattern through recognizing, reformulating, understanding, and solving of the problematic experience. This pattern can be described using an eight-level scale called Assimilation of Problematic Experiences Scale (APES) (Stiles, 2001).

Research Question and Hypotheses: The study aims to examine how change occurs during Prolonged Exposure Therapy, where people overcome a traumatic experience, and on the other hand, what causes people to avoid and distance themselves from therapeutic mechanisms. Understanding the exact mechanisms behind Prolonged Exposure is crucial for improving clinical results and expanding therapy prevalence.

Method: The current study is a secondary analysis of data collected for clinical research by the Hadassah Hospital's Centre for Research and Treatment of Trauma, researching early therapeutic intervention after traumatic events (Shalev et al., 2012). Two case studies were selected from the general population, where participants were diagnosed with PTSD and treated with Prolonged Exposure. One succeeded in losing the diagnosis after therapy and the other did not. Analysis of therapy session videos was done using Assimilation Analysis, a qualitative psychotherapy method for examining change processes in relation to treatment outcomes, based on the Assimilation Model (Honos-Webb et al., 1998, 2006; Stiles et al., 1990, 1991) . Several studies have been conducted using this method on the treatment of trauma victims (Osatuke & Stiles, 2010; William et al., 1999). The study also used participants' original clinical assessments, produced with a CAPS clinical interview.

Main Findings: Analysis presented findings that are consistent with research literature and brought about conclusions that are consistent with CAPS assessment for evaluation of therapy success. The study succeeded in describing how change occurred in Prolonged Exposure Therapy in both case studies: How habituation of anxiety evolved or, on the other hand, how avoidance was continued; how processing the experiences of exposures helped participants feel more comfortable and accept the difficulty that has been accompanying them since they were exposed to the trauma; what an internal conflict of a patient, trying to avoid remembering and describing what traumatized him, looks like, and what the therapist's help looks like; what mild dissociations that can be missed look like; and how treatment of current trauma can relieve stress of earlier traumas.

Conclusions: This study's main contribution is an external point of view enabling observation of the change process in Prolonged Exposure Therapy, and a description, rooted in participants' personal context, of advancement and regression processes during therapy. This observation enables interpretation of therapist interventions in a new perspective and adds a new point of view on the therapist's role. Follow up research can study whether using the Assimilation Model can refine the therapist's role in emotional processing. Observing traumatic experiences as a collection of distinct experiences and their interpretation as an active voice, the development of which can be tracked, might help decrease rates of early dropout or lack of success. Follow up research seeking methodological expansion of the Assimilation Model may use in vivo exposure in Prolonged Exposure Therapy, to track changes in behavioral symptoms like avoidance, in relation to the development of the assimilation process.