The present application is a continuation proposal for an ongoing longitudinal study of the effects of exposure to conflict and violence on the mental health and behavior of Palestinian and Israeli youth. Three cohorts of youth (originally ages 8, 11, and 14) have been assessed three times at one-year intervals. Analyses of the data collected through June 2010 have shown that exposure to ethnic-political and war violence is related to subsequent post-traumatic stress symptoms and aggression directed at peers in all cohorts. The goals of the current proposal are to continue analyses directed at our original specific aims with the three waves of data collected by June 2010 and to re-interview youth in all three cohorts, but with a particular focus on the oldest cohort (age 20 in 2013), to address three new aims. We will examine clinically significant mental health and aggressive/antisocial problems that we have not previously assessed and that should be associated with persistent exposure to political violence. In addition, we will examine potential protective factors that we did not previously assess (e.g., civic engagement, constructive activities, political activism, post traumatic growth). We note that our focus for these two aims will be more intense on the oldest cohort, our first to reach early adulthood, a period in which new opportunities and experiences present challenges to adjustment, and when age-salient protective factors may moderate the impact of persistent exposure to violence. Finally, for all age cohorts, we propose to extend our examination of the role of emotional reactivity in response to ethnic-political violence exposure by collecting bio-markers (e.g., cortisol) and assessing skin conductance in response to viewing a video depicting interpersonal violence. This will allow us to test emotional processes (e.g., dysregulated stress response systems) that might account for the long-term effects of exposure and distinguish between those highly exposed youth who display more externalizing problems and those who display more internalizing problems.