The purpose of this study was to identify the characteristics of psychotropic drug use and abuse by drugs addicts. The results are based on data from OPPIDUM (Observation des Produits Psychotropes Illicites ou Détournés de leur Utilisation Médicamenteuse), an annual survey primarily concerned with the consumption of licit and illicit drugs. The study involved 3373 patients recruited during october 2004 from 109 health centers. The main trends observed were an increasing interest for opioid maintenance treatment by methadone versus buprenorphine high dosage (patients treated by methadone are mainly represented for the first year of the OPPIDUM program), some changes in illicit drugs uses (increase in sniff and decrease in intravenous injection) and changes in the grading of the most consumpted benzodiazepines (decrease in flunitrazepam consumption and increase in clonazepam consumption). Main warnings concern the buprenorphine illicit use leading to firstly dependence and the illicit use of some benzodiazepines, especially clonazepam.