This dissertation investigates the scope of the psychoanalytic approach to the new symptoms which does not obey the logic of repression, but are marked by manifestations of impulsivity among which stand out the passages to the act. Our investigation started from the Freudian s construction that resulted in the notion of Agieren in English acting out. We also used the theoretical contributions of Lacan, who affiliated in psychoanalysis the term passage to the act that originated in psychiatry, to demarcate a nuance in the field of acting out, and so, to reset the two concepts. We intend to place the differential that brings the psychoanalytic knowledge to understand the passage to the act, situated as a feature of the new discontent in culture.