Military duties place personnel at unique risk for chronic pain. The Armed Forces is concerned about increasing reports of prescription opioid misuse and overreliance on medications, and is seeking to expand its chronic pain management (PM) approaches. Thus, it is essential to thoroughly investigate the non-pharmacological approaches to chronic PM that the Department of Defense (DoD) and Veterans Health Administration (VHA) are making available, including complementary and alternative medicine (CAM) treatments. This application is to expand data collection and reanalyze a unique longitudinal data set of cohorts returning from deployment to Afghanistan and Iraq in order to: a) determine how CAM/non-pharmacological PM approaches are used to treat chronic pain, b) explore if CAM/non-pharmacological PM are substitutes (or complementary) to opioid use; and, examine long-term outcomes in cohort members treated for chronic pain. Specifically: Aim 1: Describe the prevalence of postdeployment chronic pain by source and severity for active duty and reserve component Army members. Describe the prevalence and utilization (organization, duration, and intensity) of key PM clinical services used postdeployment for Army members with chronic pain. Aim 2: Investigate for which subgroups (e.g., gender, TBI), and in which health care environments, CAM services are used to treat chronic pain as a complement with prescription opioids, or as a substitute for prescription opioids. Aim 3: Investigate whether utilization of CAM as part of chronic PM is associated with postdeployment outcomes spanning 3 to 5 years postdeployment. This application will expand the Substance Use and Psychological Injury Combat Study (SUPIC) by including members from additional cohort years, extending the follow-up period, and deriving new measures specific to pain diagnoses and pain treatments. The application is innovative in its: a) focus on services for cohorts returning from deployment in FY2008-2014, b) collection of longitudinal data up to 5 years follow-up, and c) merging and analysis of person-level health system data from the two health care systems responsible for postdeployment medical services: DoD's Military Health System (MHS) and the VHA. We estimate that 120,000 cohort members will be identified with chronic pain within the first few months of return from a deployment to Afghanistan/Iraq. Because longitudinal data inclusive of MHS and VHA services are analyzed, this application is uniquely positioned to track over time, at the system-level, the extensiveness of CAM/non- pharmacological PM and the prevalence of opioid use for returning members, and, at the person-level, the joint use of PM services with use of opioids, and the association of different PM approaches with a 'recovery' trajectory (gradual improvement), or less favorable outcomes such as substance use disorder, increasing comorbidity, or a 'chronic trajectory.' These findings will assist DoD and VHA decision-makers to improve current patterns of care and to reduced distress and morbidity among injured and ill service members.