Several lines of development are outlined f.i. that of Freud, Piaget, Erikson and Mahler. The hypothesis is that a fixation at a specific moment in the line of development — by a psychotraumatic event or by a psychotoxic, micro-social milieu — gives a specific disease. The time of developmentfixation is correlated with specific categories of diagnosis. Freud correlated development-fixations, especially of the drives, with specific diseases and specific categories of diagnosis.
Mahler's subphases of the separation — individuation phase are correlated — if a fixation occurred — by Althea Horner with circumscript categories of diagnosis. The capacity to make object-relations and to maintain object — and self-constancy is central in Mahler's opinion. More categories of diagnosis are correllated in this article with fixations or regressions in the development.