Since the Second World War, the question of group psychology became not only a notorious question among psychologists (Solomon Asch, Henri Tajfel) but also philosophers (Theodor Adorno or Erich Fromm). Today however, social psychology is mostly interested in the study of individual minds. In my presentation, I would like to test the hypothesis that the application of the notion of PTSD to a community (either national, or otherwise historically created) is hermeneutically promising. In particular, it offers a good understanding of sometimes incomprehensible behaviors of young democracies, and potentially helps to think of rhetorical solutions and strategies to deal with these behaviors (populism, illiberalism among others). Recent works on cultural and historical embedment of “mental disorders” seems to be a helpful means to make sense of the complexity of the trauma and of its consequences, both on individual and collective level.