In the study of Adolescence, the models currently practised reflect the influence of deterministic and mechanistic theories both in medicine and in psychology. Adolescence appears closed between biology , drivers and social behaviour which influence clinics, health education and research. These epistemologies have the effect of forming a cultural image of adolescents which are adaptive to the theories that design it, closing them in something like an epistemological cage.

In clinical sciences these theories reduce adolescents to the problem that they report, to biological knowledge and to techniques, while profound questions, resources and possibilities which find expression also in suffering, require "qualitative" epistemology more than "quantitative," as appears from the results of the interactionist experimental epistemology and from the relativity of biological reactions.

The study of Adolescence, with a phenomenological approach, allows to characterise this period of life like a specific revelation of the mystery of human existence that, with a likewise mysterious development of new logical, emotional, affective, existential structures, is asking a real sense to give to the new "words" of life discovered during this time: "love," "truth" and "beauty."

In this perspective Adolescence means: entrance into the mystery of existence discovering possibilities and limits, its teleonomy and its pathos.

The human being , starting with Adolescence feels himself called to build a unitary "theory" , that unconsciously and/or consciously could orientate him in planning, knowing, feeling, perceiving, building reality. A positive existential reality is an arrival point and it is coherent with a new concept of health.

Existence is designed like the construction of time and space "opportune" (kairos), the man and the "Other" could create as possible answers ( self possible) to the fundamental questions of existence in order ( genetic self/ideal self ) to build a human "realised" identity (real self ) capable of hoping, willing and choosing.

"Kairology", the hermeneutics born in 1993 for a non reductionist interpretation of Adolescence and human nature, is applied with noteworthy results to research, clinics and medical education in the Adolescentology Dept of Ambrosiana University, the first University department dedicated to Adolescence, Kairology has been seen proved of giving more dignity to clinical and scientific work and to adolescents as human persons.