Preventive mental health measures can be properly planned only if the various factors leading to the adolescent's personality structure are extensively investigated. Starting with the specific attitudes of a couple towards genetic counselling, the disadvantages of urbanization and of the dissolution of the traditional extended family are discussed with regard to their effect on the younger members. Data are produced concerning the child-rearing practices of Greek in comparison to American parents and their effect on the adolescent's emotional life. Extreme dependence on the family, pressure for school achievements, lack of sexual education, etc. are characteristic of the stresses a Greek adolescent undergoes. Socio-cultural conditions, like immigration, adoption, etc. are shown to have a different psychological effect on an adolescent in Greece than in America. Specific stresses regarding the adolescent's future, like preparing for university entrance examinations, are discussed and preventive measures are proposed.