The DSM has led clinicians to abandon the term "neurosis". However, the term "psychosis" still remains, even though its modern description, an "a-theoretical" approach, challenges its theoretical relevance. From a clinical point of view, psychosis refers to a disrupted link to reality. This goes back to Freud's writings, where he spoke of the conflict between the ego and reality. He formulated two distinct theories on this question: one dealing with the early development of reality testing, the other with the phenomenon of psychosis. Our work aims to show how Freud developed these theories and suggests connecting links between them. Thus it is possible to outline an "original psychoanalytical psychosis", on which Freud's successors later founded their own conceptions of psychosis, conceptions that in fact often contradict each other. The Freudian theory of psychosis emerges as a rather coherent construction, although it leaves many questions - in particular clinical questions - unanswered, and left Freud himself not entirely satisfied. The word "psychosis" has today lost its dialectical partner, "neurosis", and covers a complex and rather incoherent theoretical field. Its survival demonstrates its clinical usefulness as a descriptive tool; although one should probably exercise caution when using it in a more theoretical sense. (PsycINFO Database Record (c) 2006 APA, all rights reserved) (journal abstract)