Abstract
The concept “adolescence” is relatively new. Not until the end of the nineteenth century and the beginning of the twentieth century was this period of life described as being especially characterized by storm and stress. G. Stanley Hall was the first to introduce this expression in relation to adolescents. Since then other contributors to the theory of adolescent psychology have taken over the expression. Gradually this point of view has acquired the opinion that it is impossible to differentiate between normal and pathological development during adolescence as well as maintaining the optimistic expectation that young people with severe pathology will outgrow their troubles.
The article describes different theoretical views of psychological development during adolescence. The aim has been to underline the importance of being able to differentiate between normal and abnormal development through a review of the theoretical considerations and specifically to find a theoretical foundation for distinguishing between normality and borderline conditions which manifest themselves during adolescence. For this last purpose Mahler's theory is found useful, especially as it has been understood by Masterson. Futhermore Blos's description of adolescence, as a second individuation process characterized by regression, helps in understanding why this phase of development is so vulnerable. □ Adolescence, development, borderline, psychosis.