Abstract
Etiologically, adolescents considered borderline by the criteria in common use are on a continuum between primarily biological and primary psychological disorders. Depression is common, and may be masked (in many cases of ulcer, anorexia, substance abuse, school avoidance) or overt (viz., early onset endogenous depression, hysteroid dysphoria, cases with severe deprivation). Illustrative cases are provided, along with recommendations for treatment.