Blatt and colleagues (1996) found that severity of psychopathology in seriously disturbed, treatment-resistant, hospitalized adolescents at the beginning of treatment was positively correlated with the degree to which these adolescents were involved in describing their parents. At the end of long-term, intensive, psychodynamically oriented, inpatient treatment of these very troubled adolescents, reduction in the severity of psychopathology correlated significantly with increases in the development of the structural organization of descriptions of mother, father, self, and therapist. These findings suggested that treatment of seriously disturbed, treatment-resistant, adolescent and young adult inpatients seems to involve at least two primary dimensions: 1) disengagement from an intense involvement with parents and 2) development in the structural organization of representations of self and a significant new figure, the therapist. The present study extends these earlier findings by examining changes in the description of a "significant other" that each patient elected to describe at the beginning and the end of treatment. Clinical improvement over the course of treatment was significantly correlated with developmental progression of the significant figure each patient selected to describe (from a grandparent to a close friend) as well as with progression in the developmental organization in which this significant other was described. These findings suggest that treatment of seriously disturbed adolescents and young adults involves a disengagement from an intense involvement with primary caregivers to involvement with others outside the family matrix and the developmental elaboration of the representation of these figures.