On the way to becoming autonomous, the adolescent sometimes meets with solitude. Some pathological conduct, such as running away or “ false-starts ”, seem to bear witness to this, being both an expression of the malaise the adolescent feels, and an appeal to the other. As a relations theory, the theory of attachment offers a model for understanding these situations where coherence must be centred on the interpersonal and on the possibility of family therapy interventions. In this direction the two concepts of “ resonance ” and of “ floating object ” hold much interest.