Objective: this study presents an analysis of the common functions of addictive behaviors based on speeches and behaviors of heroin addicts in aftercare.The abstinence position allows to identify what is seek and achieve when there is no addictive behavior.The analysis of these functions is linked with a system of actions model.Method: the recording of semi-structured interviews from 12 heroin addicts, abstinent, in aftercare since more than a month allowed a content analysis of the speeches based on two categories: abuse and abstinence.A comparative analysis of these two categories allows to establish the functions of addictive behaviors.Results: addictive behaviors have two functions: an avoidance of psychical activity and an Ego restoration.As there is no addictive behavior, these two functions have other substitutive ways as intensive physical activity, boulimia, psychical rumination.The variety of these substitutive ways indicates variable potentiality of psychical reorganisation according to the subjects and the organisation of their system of actions.Conclusions: the addictive behaviors are positive solutions on the psychological point of vue even if they implicate somatic and social dammages.