[Borderline syndrome in adolescence. Discussion apropos of a clinical case]

The "border-line" syndrome in adolescence is typified, not only by a suggestive symptomatology, but above all by a stable and specific abnormal structure of the ego originating in a developmental arrest. This syndrome is discussed with reference to the clinical case reported here. Although, from a purely semeiological point of view, this adolescent had an acute psychotic episode, this condition was related to a transformation of the ego in which the separation-individualization process was involved. The treatment which was initiated is based on this psychopathological explanation.