" Smoking weed it gets you over the hump": " : Cannabis co-use as a facilitator of decreased opioid use among people who inject drugs in Los Angeles, California

Introduction: Opioid overdose mortality rates have surged dramatically in the last decade due largely to fentanyl in the illicit US drug supply. As of June 2024, 38 states, three territories, namely US Virgin Islands, Guam and the Northern Mariana Islands, and the District of Columbia, allow the medical use of cannabis products. However, there remains limited qualitative community-based evidence on the role of cannabis co-use among opioid using and injecting populations. In this study, we present data from people who inject drugs (PWID)'s co-use of cannabis-opioid. Methods: We conducted 30 one-on-one semi-structured interviews with PWID from July 2021 to April 2022 at two community sites in Los Angeles, CA, near a syringe service program and a methadone clinic. Interviews were recorded and transcribed. We used constructivist grounded theory methods for identifying and comparing the emerging themes that appeared across transcripts to construct a conceptual explanation of how PWID co-used cannabis and opioids. Participant inclusion criteria included injection drug use, opioid and cannabis use, English fluency, and age 18+ years. Results: PWID described that cannabis co-use assisted in developing patterns of reduced opioid use in a number of ways: 1) maintain opioid cessation and/or adhere to opioid use disorder treatment by managing cessationspecific symptoms, 2) manage symptoms of opioid withdrawal episodically and, 3) decrease opioid use due to low barrier accessibility of cannabis. Discussion: Participants reported myriad benefits of opioid and cannabis co-use for reducing patterns of opioid use. These findings have two major harm reduction implications for PWID: 1) the distribution of cannabis via low threshold peer programming and interventions can facilitate changes in opioid use patterns and 2) access to cannabis co-use, potentially alongside existing Medication for Opioid Use Disorder, in treatment settings may improve efficacy of uptake and treatment outcomes and goals for individual PWID.