This dissertation intends to demonstrate how the delusion of a psychotic patient is structured by transgenerative family relationships. The concept of generative psychical transmission is used to prove that the psychical development of every person is constituted by the intersubjectives relations, having their foundations in the families relationships. The person is the maker as well as it is made through these relationships. It is tried to demonstrate this process under psychoanalytic focus when working with psychotic adolescents. The author proves the expectations of the families when a new member becomes part of it and too the family dynamic when they have adolescents members. The theory of psychoanalytical family therapy is used to analyze a clinical situation demonstrating the transgenerative psychical transmission in the construction of delusion of a psychotic adolescent and their family history in a public mental hospital.