Mental contamination-an internal experience of dirtiness evoked in the absence of physical contact with an external source-has been linked to the development and maintenance of posttraumatic stress disorder (PTSD) following exposure to sexual abuse or assault (Adams et al., 2014; Badour et al., 2013; Brake et al., 2017). Mental contamination has been associated with greater PTSD severity (Rachman et al., 2015) and higher elevations in specific PTSD symptom clusters (particularly those of intrusive reexperiencing, negative cognitions/mood, and arousal/reactivity; Brake et al., 2019; Fergus \& Bardeen, 2016). Additionally, trauma-related mental contamination has been linked to a number of negative posttraumatic emotions such as shame, guilt, disgust, and anger (Fairbrother \& Rachman, 2004; Radomsky \& Elliott, 2009) Despite clear and consistent links between mental contamination and problematic posttraumatic outcomes following sexual trauma, there is a dearth of research investigating how existing or promising new interventions for PTSD impact mental contamination.
Cognitive Processing Therapy (CPT) is an efficacious and effective 12-session manualized cognitive-behavioral intervention for PTSD that is considered a gold-standard empirically-supported treatment for PTSD that is recommended by the American Psychological Association (APA, 2017). In addition to PTSD symptom improvement, CPT has also demonstrated benefit for improving feelings of shame and guilt, which are often seen among individuals with trauma-related mental contamination (Nishith et al., 2005; Resick et al., 2002, 2008). Cognitive reappraisal, a primary technique employed in CPT, involves challenging one's view of an emotionally-eliciting situation to alter its emotional impact (Gross \& John, 2003). However, some investigators have suggested that cognitive reappraisal may be less effective in targeting moral emotions such as shame, guilt, and self-disgust that are based on an individual's standards and virtues (Finlay, 2015). Self-compassion (SC; i.e., self-directed care and kindness; forgiveness; and feelings of common humanity; Neff, 2003) has been proposed as an alternative method for addressing trauma-related shame and preliminary evidence suggests a 6-session self-compassion intervention may have benefit for reducing both PTSD symptoms and trauma-related shame (Au et al., 2017). Given the centrality of shame, guilt, and self-disgust to the experience of mental contamination, and the fact that mental contamination often arises in response to experiences involving moral violation or betrayal (Millar et al., 2016; Rachman, 2010), a SC intervention for PTSD may also offer promise as a standalone or adjunctive intervention for reducing trauma-related mental contamination. A test of these interventions for their impact on reducing trauma-related mental contamination is needed.
The current study will use Single Case Experimental Design to isolate and evaluate the effects of CPT and SC in reducing both PTSD symptoms and trauma-related mental contamination among individuals with PTSD resulting from sexual trauma.
Aims: 1) explore whether participants demonstrate reductions in mental contamination and PTSD symptoms in response to 12-sessions of CPT or 6-sessions of a SC intervention; 2) evaluate whether presentation of either treatment first yields differences in symptom reduction for PTSD and/or mental contamination symptoms; 3) evaluate whether the addition of the alternative module will enhance reductions in PTSD symptoms and mental contamination; 4) evaluate if such reductions are maintained during follow-up.
Visual inspection analysis and statistical methods will be used to draw conclusions regarding the effects of the interventions on PTSD symptoms and mental contamination.