Adolescence is a period of instability caused by biological changes and restructuring of the personality. An immigration background renders the process of identity formation even more difficult or fragile, with an additional burden coming from persecution and harassment. Three case studies of mentally disturbed adolescents with different immigration backgrounds illustrate the problems in diagnosis and psychotherapy. All three cases share a common feature—the particular influence of the native country on the psychic disorder of the adolescent, be it a suitable target of narcissistic self-aggrandizement, a reactivated metaphor of the past or a deposited conflict. I point out and discuss the danger of diagnostic colonization and activation of perpetrator-victim constellations—such as the Nazi past in the present. Offering a transcultural transitional space as a container yields a therapeutic approach to the different worlds of these borderland adolescents.