Trauma-related Shame Predicts Somatoform Dissociation Symptom Severity in PTSD Treatment

Abstract
Background
Somatoform dissociation symptoms, physical symptoms with no known organic cause, account for nearly 25% of all visits to primary care facilities and affect up to 17% of the general population. Moreover, somatoform dissociation symptoms have a high comorbidity with trauma exposure and posttraumatic stress disorder (PTSD). Shame has been implicated as a mediating factor in this relationship; however, it is unknown whether changes in feelings of shame impact the severity of somatoform dissociation symptoms across time. We investigated the relationship between shame and somatoform dissociation symptom severity before and after PTSD treatment. We predicted that decreases in shame would be associated with decreases in severity of somatoform dissociation symptoms.

Methods
Participants were 46 individuals with histories of interpersonal trauma and current PTSD receiving empirically based outpatient trauma-focused treatment (e.g., cognitive processing therapy, prolonged exposure) over three to five months. Participants reported a diverse range of socioeconomic statuses and sexual orientations, and twenty-four percent of participants reported having minoritized racial/ethnic identities. Participants completed self-report measures before and after treatment, including measures of childhood trauma (childhood trauma questionnaire), PTSD symptoms (PTSD checklist for DSM-5) , somatoform dissociation symptoms (Screening for Somatoform Symptoms-7), and trauma-related shame (Trauma Related Shame Inventory).

Results
Linear regression using robust standard errors revealed that, after controlling for demographic variables (age, race, ethnicity, sex assigned at birth), baseline childhood trauma severity, and PTSD symptom severity, pre-treatment feelings of shame significantly predicted pre-treatment somatoform dissociation symptom severity, such that higher shame was associated with more severe somatoform dissociation symptoms, b=0.34, SE=0.16, t=2.13, p=0.039. In addition, changes in shame (difference score post-pretreatment) significantly predicted a change in somatoform dissociation symptom severity (post-pretreatment), such that greater decreases in shame across treatment were associated with greater decreases in somatoform dissociation symptom severity, b=0.39, SE=0.16, t=2.38, p=0.025.

Conclusions
These novel results suggest that trauma-related shame may play an important role in the relationship between trauma exposure and somatoform dissociation symptoms. As such, treatments that address trauma-related shame may also be effective in decreasing somatoform dissociation symptoms. Additionally, those presenting to primary care facilities with somatoform dissociation symptoms may benefit from the assessment of lifetime trauma exposure and trauma-related symptoms followed by trauma-focused treatment when appropriate.