An adjunctive human-animal interaction intervention for veterans with PTSD: study protocol for a randomized controlled trial

Background Posttraumatic stress disorder (PTSD) rarely remits over time, and if left untreated, leads to significant distress, functional impairment, and increased health care costs. Fortunately, effective evidence-based treatments (EBTs) for PTSD, such as Prolonged Exposure (PE), exist. Despite their availability and efficacy, a significant number of individuals with PTSD do not initiate treatment when offered or dropout prematurely. One proposed theory suggests that the emotional-numbing symptoms of PTSD (e.g., blunted affect, apathy) can serve as a barrier to engaging in, and successfully completing, treatment; and the broad human-animal interaction (HAI) literature available suggests that HAI can potentially reduce emotional numbing related to PTSD. Accordingly, this manuscript describes an ongoing, federally funded, randomized controlled trial testing the efficacy of RESCUE, an HAI intervention, as a viable adjunctive treatment component for PE. Methods/design The study will include 70 veterans with PTSD treated at a Southeastern Veterans Affairs Medical Center (VAMC). All participants in the trial receive up to 12 sessions of PE. Participants are randomly assigned 1:1 to (1) volunteer at a local animal shelter or (2) volunteer at a community agency of their choice as part of their in-vivo exposure exercises for PE. Outcomes will be examined via standard clinical interviews, self-report questionnaires, and thematic interviews. Discussion It is hypothesized that participants in the HAI condition will report greater decreases in emotional-numbing symptoms and increased treatment compliance and completion rates relative to those in the community volunteer condition. If successful, RESCUE, could be easily incorporated into standard PE and broadly disseminated. Trial registration ClinicalTrials.gov. ID: NCT03504722. Retrospectively registered on 2 May 2017.

Evidence for subjective emotional numbing following induced acute dissociation

The aim of the study was to examine the effects of acute dissociation on emotional responsivity in healthy individuals. We used a previously validated technique (mirror-gazing, Caputo, 2010) to experimentally induce acute dissociation in non-clinical participants and assessed post-induction subjective responsivity (ratings of valence and arousal) to standardized emotional images. Fifty non-clinical participants were randomised to either the dissociation induction (n=25) or control conditions (n=25). The dissociation manipulation effect was corroborated by a significant post-induction elevation in state dissociation in the dissociation-induction group relative to controls (p=.004). The dissociation-induction group rated negative (p=.028) and neutral (p=.025) stimuli as significantly less unpleasant than controls. There was also a non-significant trend for positive stimuli to be rated as less pleasant by the dissociation-induction group compared to controls (p=.060). These findings provide experimental evidence for the short-term alleviation (i.e., emotional numbing) of negative affect during dissociative states, which may serve as a coping mechanism for some individuals. However, this tendency of emotional numbing also reduced positive affective responses to pleasant stimuli to some extent. Further investigation of dissociative phenomena and their impact on emotional processing appears warranted.