Abstract: In his article Ignatenko traces back the evolution of the mental development concept from the moment when it was first mentioned in Zigmund Freud's psychoanalysis till the time when Gilles Deleuze offered his version of mental development being under the influence of Сarl Jung's analytical psychology, Jacques Lacan's structural psychoanalysis, Michel Foucault's anti-psychiatry and others. The researcher focuses on the interdisciplinary sphere formed by psychoanalysis, psychiatry, psychology, philosophy of language, linguistics, philosophy and literary critics which views the concept of mental development from the point of view of their complementary aspects. The author defines drawbacks in Freud's theory of mental development and how Deleuze overcame them. The research involves the method of comparative analysis of previously reconstructed conceptual systems offered by Freud and Deleuze. When reconstructing the method of Deleuze's philosophy, the author has used the transdisciplinary approach. Ingatenko concludes that Deleuze kept to the instrumentalist explanation of the mission of 'Self' development, the purpose of mental development being, in the last analysis, relativization of Self, or approaching the impersonal and pre-individual state when space and time do not act as impassible limits for self-identification. The author of the article also offers a number of original ideas including the idea about the evolutionist nature of Michel Foucault's philosophy and the absence of the apologetics of psychopathology in Deleuze's philosophy, which he used only as the analogy to the impersonal and pre-individual state, etc.