Recent studies indicate that veterans who engage in suicidal behavior have a history of traumatic brain injury (TBI), and veterans with a history of TBI engage in suicidal behavior. Existing research also suggests an association between suicidality and executive dysfunction (e.g., impaired decision making). To date a clearly defined study has not been conducted to explore the relationship between executive dysfunction as a multidimensional construct (i.e., decision making, impulsivity, concept formation, and aggression) and suicidal behavior in the vulnerable population of those with a history of moderate to severe TBI. Increased understanding regarding this at-risk population is necessary to facilitate the creation of appropriate assessment strategies and interventions. This study will assess decision making in the context of an interaction between suicide and TBI. Findings will also allow for exploratory analyses aimed at identifying associations between performance on measures of executive functioning and psychological distress. Toward this end, the present study seeks to compare test performance among four well-defined groups of veterans: (1) those with moderate to severe TBI and a history of suicidal behavior; (2) those with moderate to severe TBI and no history of suicidal behavior; (3) those with no TBI and a history of suicidal behavior; (4) and those with no TBI and no history of suicidal behavior. This grant proposal is in direct support of the Rehabilitation Research and Development goal of maximizing functional recovery in those with TBI by potentially: 1) increasing clinicians' ability to identify neuropsychological correlates of suicidal behavior for those with moderate to severe TBI; 2) identifying psychometrically sound measures of executive functioning that correspond to real-life behaviors that impact treatment response and recovery; 3) facilitating the creation of innovative assessment techniques and psychosocial interventions (e.g., safety planning) to minimize complications in the management of suicidal behavior due to TBI-related impairments; and 4) creating a basis for further and much-needed research in this area. Ultimately, findings from this study would both contribute to clinicians' ability to identify veterans with TBI who are at risk for suicidal behavior, and create a foundation on which to base further research regarding the relationships between cognition, emotional distress, and suicidality in TBI survivors.