Moral Injury (MI) is the lasting psychological, biological, spiritual, behavioral, and social impact of perpetrating, failing to prevent, bearing witness to, or being the victim of acts that transgress deeply held beliefs about right and wrong. There is widespread acceptance of and interest in MI, but this has outpaced scientific examination. To date, the knowledge gaps are: (1) no consensus definition of the symptoms that comprise the MI syndrome; (2) no gold standard clinical assessment measure of MI as an outcome; (3) no definition of functionally impairing clinically significant MI; (4) no epidemiological studies of the prevalence of different types of potentially morally injurious events (PMIEs) and MI; (5) insufficient evidence that MI has incremental clinical and explanatory validity; and (6) a lack of information about risk and resilience and the clinical care needs of Veterans with MI. In this project, we have the following five aims: (1) to determine the US Veteran population prevalence of exposure to different types of PMIEs. We have shown that different types of PMIEs are associated with a unique constellation of problems. We hypothesize that non-perpetration based PMIEs (e.g., high stakes betrayal by trusted others) will be most prevalent; (2) to generate an optimally efficient threshold severity score on the Moral Injury Outcome Scale (MIOS) that suggests probable functionally impairing MI. Currently, there is no method that can be used by clinicians and researchers to determine the clinical significance of MI as an outcome. This means that there is no way to distinguish moral frustration and moral distress, which are common, from MI, a low base-rate clinical problem greatly affecting functioning, quality of life, and potentially requiring treatment. A threshold score for caseness will help clinicians and researchers screen and assess MI. We will use Receiver Operating Characteristic analyses, using upper quartile scores on a quality of life and functioning measure as the criterion; (3) (primary) is to determine the prevalence of MI cases and to explore prevalence by type of PMIE (we have no predictions about whether different types of PMIEs will be associated with greater or lesser case prevalence). A secondary aim is to determine the normative mean severity (and SD) of MIOS total and subscale scores and to explore these variables by type of PMIEs (or no PMIE endorsement). We hypothesize that Veterans who endorse perpetration-based PMIEs will have higher MIOS shame scores relative to those that endorse non-perpetration-based PMIEs, and vice versa; (4) to examine the incremental validity of MI relative to PTSD and Depression, by testing the association between MIOS scores and a measure of quality of life and functioning, relative to PTSD and depression. We predict that MI symptoms will account for unique variance in functional problems; and (5) to conduct qualitative interviews of randomly selected MI cases and matched Veterans who ...