The OPPIDUM program was first created in 1990. It is an annual, repeated, cross-sectional, nationwide, multicenter program. Data are provided directly from users of psychoactive substances (PAS) seen in substance abuse treatment facilities. The OPPIDUM program includes sociodemographic data, data on the first PAS used and leading to dependence, data on PAS use in the week prior the interview and the modality of use. The OPPIDUM program contributes to characterize patterns of SPA use and detect changes in modalities of use or/and in users profiles. It relies on the acceptability and adhesion of the growing number of participating substance abuse treatment facilities for more than 30years, giving informative data at the national and regional level. In 2023, the OPPIDUM program gathers data from about 117,822 participants describing 239,959 patterns of PAS use (with more than 5000 participants each year). In this article, we reviewed the success of the oldest program of the French Addictovigilance Network (history, development, evolution and contribution) for the assessment and surveillance of substance abuse.