The present invention relates to mazindol for use in the treatment of dependence and substance use disorder, wherein the substance is an opioid, a composition comprising mazindol and optionally a pharmaceutically acceptable carrier or excipient and/or a diluent, for use in the treatment of substance abuse disorder, wherein the substance is an opioid, and a method of treatment of substance abuse disorder comprising administering mazindol or composition comprising mazindol to a subject, wherein the substance is an opioid. The opioid is preferably heroin.