This book presents current research results in clinical psychology, health psychology and psychiatry concerning the links between complex post-traumatic syndromes, dissociative states and borderline functioning. This research project, which spans over several years, consists of studies on the disruption of identity with excluded and marginalised persons by combining the clinical with the experimental approach. An exploratory comparative study is based on an intensive clinical investigation of people suffering from social precarity, belonging to different clinical subgroups: long-lasting unemployed people, homeless people, refugees and political asylum seekers and prisoners suffering from drug addiction. The authors used an integrated qualitative and quantitative methodology, combining semi-structured interviews with psychometric, projective and expressive tests.