Introduction of Long Acting Buprenorphine in France
The current available pharmacological treatment formulations (i.e., daily formulations of buprenorphine or methadone) for OUD in France may have several inconveniences, such as: compliance, burden of daily intake, and risk of misuse; that may hinder their effectiveness. Long acting formulations of buprenorphine (LAB) such as Buvidal have been developed to favor retention and compliance and minimize the risk of diversion. Previous studies are promising on the advantage of LAB to treat opioid addiction, however more evidence is needed in the French healthcare context. However, in addition to randomized clinical trials, the French National Healthcare Agency (HAS "Haute Autorité de Santé") recommends conducting "real-life" studies (i.e., in naturalistic conditions) during the development of a medication and the use of "Patient Reported Outcome Measures" (PROMs) to analyze patient quality of life and/or other measures relevant to patients (e.g., severity, efficiency), without interpretation of the answers by a health professional. In this regard, our study proposes to use the Addiction Severity Index (ASI) self-report questions and several scales on treatment satisfaction and quality of life to collect the patient's opinion of perceived changes following the use of Buvidal.

Main objectives:

The objectives of this prospective open observational study, in naturalistic conditions, are to examine in individuals with an opioid use disorder, over a period of 6 months after LAB treatment initiation: the change in substance addiction severity and the changes in health-related quality of life, craving, opioids and other substance and non-substance uses and misuses, alcohol, tobacco and non-substance addiction severity, satisfaction with LAB treatment, severity of others domains related to addiction severity (i.e., medical, social, psychological) and psychiatric comorbidities

Main hypotheses:

Hypothesize was that LAB will be associated with a stable (if prior remission) or a reduction of the CS of "Drug use" (i.e., substance addiction severity) at 6 months compared to baseline.
Hypothesize was that LAB will be associated with a stable (if prior remission) or a reduction of opioids and other substance and non-substance uses and misuses, other substances and non-substances addiction severity, craving, severity of others domains related to addiction (i.e., medical status, employment and support, family/social status, psychological status), an improvement of quality of life and a good satisfaction with treatment at follow-ups compared to baseline.
- EligibilityCriteria: Inclusion Criteria:  To have been prescribed LAB To plan to initiate a LAB treatment in the following month To be over 18 years of age To accept to participate after an informed consent procedure  Exclusion Criteria:  To be under guardianship, curatorship or safeguard of justice To have a difficulty understand / reading the French language To have any condition incompatible with study participation (e.g., not being able to communicate by phone) - HealthyVolunteers: No - Gender: All - MinimumAge: 18 Years - StdAgeList: Adult, Older Adult - StudyPopulation: Participants included in this observational study in the French healthcare context will be recruited from the current prescribers of LAB, which are medical doctors working in Addiction Treatment Centers (i.e., Centre de Soins, d'Accompagnement et de Prévention en Addictologie (CSAPA), services hospitaliers d'addictologie) in France. - SamplingMethod: Non-Probability Sample