Examining Changes in Microbiota Over the Course of PTSD Treatment

This project will evaluate the use of 5-day intensively-delivered Cognitive Processing Therapy to treat PTSD and will aim to determine the associations between the microbiome, salivary cytokines, and the presence of and recovery from PTSD. A total of 24 participants who have experienced a criterion A trauma will be recruited. An intake assessment will be used to confirm the fit for the proposed project. Clinical interviewers with a minimum of a Master's degree in Psychology who are not providing the treatment will administer structured diagnostic interviews (CAPS and DIAMOND). If an individual meets criteria for a PTSD diagnosis based on the CAPS they will be eligible for this treatment study. Study staff will administer brief computerized assessments (e.g. Stroop task), a full self-report assessment battery, and two internet-based dietary assessments to all participants. Study staff will also collect fecal- and oral-derived microbiota and salivary cytokine samples from individuals who opt in to this aspect of the study. Study Treatment - Intensive Week-Long Cognitive Processing Therapy (CPT): The individuals in this study will undergo a course of 1-week-long Cognitive Processing Therapy (CPT-5). CPT-5 will be delivered twice per day over the course of five business days. Each 50 minute session will closely follow the CPT protocol and will be conducted by either Dr. Held, other doctoral-level psychologists, postdoctoral fellows, or other Master's level (or higher) clinicians who have received the official two-day CPT training and who are not involved in study assessments. CPT worksheets and homework assignments may be collected and copied for research purposes. Changes in PTSD severity and other relevant symptoms will be assessed before, during, and after the course of CPT using well-validated clinician-administered, self-report, and computerized assessments. Fecal- and oral-derived microbiota as well as salivary cytokines will also be assessed at various pre-treatment, post-treatment, and follow-up time points to determine whether the microbiome and cytokine levels change over the course of CPT. Participants in this study will have the option to opt out of providing these biological samples and still receive CPT-5. Semi-Structured Interview: Regardless of whether they completed the course of CPT, participants in the study may be asked to participate in one 20-40 minute semi-structured interview. The interviewer, who is a member of the research team and not the respective participant's study therapist, will ask general questions about the participant's experiences of CPT-5 and gather information about the participant's perceptions of the tolerability, acceptability, and feasibility of the intervention.