Project Summary/Abstract Posttraumatic stress disorder (PTSD) is a debilitating condition with deleterious effects on individuals and society. Evidence-based treatments for PTSD are available, including cognitive processing therapy (CPT) and prolonged exposure (PE), but response rates are suboptimal, and dropout rates are high. Patients report concerns about treatment that prevent optimal response, but evidence suggests therapists are often unaware of patients' concerns and do not intervene effectively to help their patients benefit from treatment. The purpose of this research is to refine and test an Adjunctive Writing intervention for Amplifying Response and Engagement (AWARE), which was developed to enhance outcomes in CPT and PE. AWARE integrates findings from the field of health communication and uses a writing task and guided therapist responses to facilitate improved patient- therapist communication about patients’ treatment-related concerns during existing check-ins in CPT and PE. After iteratively refining AWARE through a case series (n=4), a pilot randomized controlled trial (n=50) will be conducted to preliminarily compare CPT/PE with AWARE to CPT/PE treatment as usual (TAU). The primary aim of the RCT is to take an experimental therapeutics approach to demonstrate that AWARE is feasible, acceptable, and engages the target of improved patient-therapist communication relative to TAU. A preliminary examination will also be conducted of the effects of 1) AWARE vs. TAU, and 2) variability in patient-therapist communication on symptom improvement and treatment completion. An exploratory aim is to examine patient-therapist communication as a mechanism of improved symptom reduction and attendance in AWARE using session-by- session assessments to see if the putative mechanism precedes and predicts the outcomes. This trial is consistent with NIMH's Strategy 3.1.A, "Developing novel interventions using a mechanism-informed, experimental therapeutics approach," and can both enhance outcomes for patients with PTSD and improve the field's knowledge of processes for enhancing PTSD treatments. Further, given that AWARE is a brief intervention that can be implemented during existing check-ins in evidence-based treatments, AWARE can be easily scaled and implemented to enhance outcomes across mental health disorders. The proposed research and training plans will allow the applicant to gain essential knowledge and applied experience in 1) refining and evaluating a mechanism-based intervention to enhance PTSD treatments, 2) translating health communication knowledge to improve PTSD treatment outcomes, 3) using advanced data analyses to examine mechanisms of therapeutic change, 4) conducting clinical trials in an experimental therapeutics framework, and 5) professional development and grantsmanship. It will facilitate the applicant's transition to an independent investigator who uses treatment mechanistic knowledge to optimize PTSD treatment outcomes. This...