BACKGROUND In classical psychological terminology, the term immaturity did not make a direct link to psychiatry; it was more likely a fine description of some personality traits. As a result, in the moment it was used for a psychological examination, it meant a functional and personality diagnosis, and not a clinical approach, sometimes connected with the large area of normality. OBJECTIVE Through this paper, we want to underline a pure psychiatric vision of the meaning of this term, in the cases where the personality psychology limits are overcome and we are confronting the psychopathology aria. We present distinctly some clinical entities met in the area of adult psychiatry. Here, immaturity is seen as the main trait around which several symptoms grouped in syndromes are coming together. METHOD This presentation is a personal synthesis on theoretical aspects but based on thousands of patient cases with psychiatric disorders seen during several years – both from psychiatric perspective and under the psychology impress. We are talking not only about the cases of mental debility – of different grades (been used with the term of „immature personality structure”), as well as schizophrenic patients and everything that immaturity means in this disease – we are also talking about patients with bipolar affective disorder with early debut and conversion – dissociation pathology. RESULTS The new theoretical concept, already in use, can reflect in the building of particular recovery modalities based on the new psycho-diagnostic vision.