Borderline personality disorder (BPD) is a common mental disorder in adolescents with significant individual and societal repercussions, characterized over the long term by emotional hyperresponsiveness, relational instability, identity disturbances and self-aggressive behavior. The etiology of BPD is multifactorial and involves exposure to traumatic life events, which are present in the majority of cases. This explains the very common co-morbidity between BPD and post-traumatic stress disorder (PTSD), which involves emotionally painful memory relapses of one or more traumatic events, associated with an emotional trauma avoidance syndrome (s). ) and hypervigilance. Brain imaging studies in adolescents with BPD have shown decreases in the volume of gray matter within the frontolimbic network, as well as a decrease in frontolimbic white matter bundles. These brain changes are considered to be biological markers of TPB. However, the exact same brain changes are seen in PTSD. Although it represents more than a third of adolescents hospitalized in psychiatry, neuroscientific studies of BPD in adolescence are still scarce. The expertise we have acquired in U1077 in adolescents with PTSD offers us an exceptional opportunity to characterize in BPD with and without PTSD structural anomalies, including the hippocampus, and functional at rest, never used for hour in the teenager's BPD. Beyond that, carrying out an 18-month follow-up of the patients will allow us to assess the predictive value of these anomalies on the level of general psychopathology in all the patients studied and the intensity of the symptoms of traumatic relapse in the patients with PTSD. This modeling of disorders integrating psychopathological, neuropsychological and neuroanatomical approaches will provide the clinician with new knowledge necessary for therapeutic innovation.