The new conception of psychological trauma that arose in the 1980s with the definition of PTSD in the DSM-III was a major change compared to the previous traumatic neurosis. While the clinical features were in some way similar, the political and sociological meanings of trauma were absolutely different. At that time, the invention of PTSD was much more the consequence of a broad mutation in mentality that introduced a new moral perspective in trauma studies than of a scientific discovery. In this paper, the author underlines from an anthropological point of view the second turning point that occurred in trauma studies in the mid 1990s when large epidemiological surveys did not confirm the first hypothesis. Readdressing the issues of vulnerability and risk factors that the previous version of PTSD had withdrawn, this second conception raises new epistemological questions that stay unsolved.