Difficulty controlling anger is the most commonly reported reintegration concern among combat Veterans, especially those with a diagnosis of posttraumatic stress disorder (PTSD). In Veterans, problematic anger is associated with numerous negative psychosocial outcomes, including poor functional outcomes (both social and occupational), family discord, aggression, road rage, and suicide risk. Anger can also impede successful outcomes from PTSD treatment. Given the high prevalence of anger problems among Veterans with PTSD and the associated functional impairments, there is a clear need to develop innovative and effective anger interventions to improve functional outcomes of Veterans. The use of mobile health (mHealth) technology could provide a low-cost method to increase the reach of anger management treatments to this high-need group of Veterans. One of the mechanisms associated with problematic anger and aggression is hostile interpretation bias, i.e., a tendency to interpret ambiguous interpersonal situations as hostile. By reducing hostile interpretation bias, it may be possible to significantly reduce problematic anger and aggression and improve functional outcomes. The applicant has developed and piloted a computer-based interpretation bias modification intervention that successfully reduces hostile interpretation bias and anger outcomes. The goal of this project is to further develop this intervention for Veterans with PTSD, using mHealth technology to increase the portability of this promising approach to reduce anger and enhance occupational and psychosocial functioning. The Research Plan proposes to develop, refine, and pilot-test a mobile application version of the existing computer-based interpretation bias modification intervention for individuals with PTSD and problematic anger. The central hypothesis is that patients with PTSD and problematic anger will find this mobile intervention acceptable and will be willing to use it to reduce their anger difficulties and improve psychosocial and occupational functioning. The proposed research project will address the following Specific Aims: Aim 1(a): To develop a mobile interpretation bias modification intervention entitled Mobile Intervention for Reducing Anger (MIRA) for Veterans with PTSD and problematic anger; Aim 1(b): To use a successive cohort design to refine the MIRA intervention for Veterans with PTSD and problematic anger; and Aim 2: To: a) evaluate the feasibility of recruitment, randomization, and retention procedures in a pilot study comparing MIRA to a contact control condition, focusing on community reintegration and functional outcomes, and b) conduct an exploratory aim utilizing psychophysiological and electronic diary monitoring to determine whether this assessment could be utilized as an outcome or mechanistic variable in a subsequent randomized clinical trial application focused on evaluating the efficacy of the MIRA intervention. The results generated will guide the d...