The specificity and the severity of psychopathology in adolescence oft
en requires a highly complex observational setting. This is due to the
important role which the setting plays in, every diagnostic and thera
peutic intervention concerning adolescents with severe personality dis
orders. This larger context entails the creation. of a setting which w
ill reveal the interactional style of the adolescent as it is expresse
d spatially, temporally, through relationships and learning stills. In
this paper, we will present a methodological illustration of the role
played by the institutional setting in the diagnostic and therapeutic
process.