PROJECT SUMMARY Posttraumatic stress disorder (PTSD) and hazardous drinking (HD: heavy alcohol use and negative alcohol- related consequences) commonly develop and co-occur following trauma exposure. The individual and public health burden of PTSD and co-occurring HD is substantial. Although there are evidence-based behavioral treatments for co-occurring PTSD and HD, they have limitations that result in many individuals not accessing these treatments and limited intervention reach – i.e., existing interventions tend to be complicated, burdensome, and require contact with an in-person therapist. Thus, there is a need to develop additional, novel interventions that use evidenced-based strategies and that have greater portability and reach. There is a nascent, scant literature evaluating such types of interventions for veterans, and we know of none aimed at the general public. The current application, therefore, seeks to refine and test a brief, self-directed, intervention for individuals from the general public with PTSD and co-occurring HD that can be delivered via text-messaging. The proposed intervention draws on evidence-based strategies from cognitive behavioral therapy (CBT) for treating PTSD and co-occurring HD, and it yielded promising findings in a recent pilot study conducted by the research team. This application seeks to refine the intervention further by testing whether theoretically-driven, evidence-based strategies from basic cognitive psychology (message framing) and social psychology (facilitating growth mindsets) result in better outcomes for PTSD symptoms and HD by addressing pilot participant feedback related to avoidance and motivation. We will identify the most efficacious intervention and test it in a fully-powered RCT. Thus, Study 1, which will recruit an adult community sample (N = 500), will test the efficacy of enhancing the CBT text message intervention with message framing (protect against loss vs. imagine future gains vs. no framing) and mindsets (provide growth mindset message for using skills vs. simple reminder to use skills) via a fully-crossed 3x2 factorial design. Study 2 will build on Study 1, by conducting a fully powered (N = 333) randomized controlled trial (RCT) that will test the comparative and long-term efficacy of the most efficacious CBT-based text message intervention from Study 1 versus an assessment only control in a community sample of adults with co-occurring HD and PTSD. This proposal is innovative in its approach to adding to the menu of treatment options for co-occurring PTSD and HD and with its evaluation of the utility of integrating basic social and cognitive psychology strategies with those from CBT. If successful, it will result in an efficacious, novel, theory-driven, low burden behavioral intervention co-occurring PTSD and HD that is readily scalable. Such an intervention could be implemented as a stand-alone intervention or be integrated into stepped-care approaches, including following ...