Jama, Sadia2025-04-242025-04-242025-04-24http://hdl.handle.net/10393/50373https://doi.org/10.20381/ruor-31045Substance use disorders can have devastating impacts on health and mortality with larger implications for society including significant economic costs to communities, families, and individuals. The prevalence of substance use, and the burden of poor health and social outcomes are disproportionately experienced by the most marginalized in society. Community based participatory research (CBPR) promotes innovative, tailored, evidence-based interventions that are designed to improve individual health outcomes and result in community and policy level change. The aim of this dissertation is to explore the value of Community Based Participatory Research (CBPR) approaches when intervening on substance use and building new knowledge on the experiences of marginalized populations that self-report the use of cannabis to manage poor mental health. This will be accomplished through systematic reviews of available CBPR peer-reviewed substance use intervention literature, and a mixed method cross-sectional CBPR research study on cannabis and mental in marginalized populations of Ottawa (Canada). Analysis will include a quality analysis of the articles that make up the systematic reviews, an iterative reflexive qualitative thematic analysis, and a quantitative analysis that will include a descriptive and regression (mixed effects model) analysis to quantify the association between cannabis use, mental health, and physical health. The findings revealed promising behavioural and community level impacts that influence the substance use outcomes of marginalized populations. The qualitative findings demonstrated that the use of cannabis within these populations can be therapeutic and often a response to an unmet health need, with participants reporting undiagnosed and underdiagnosed mental health issues and limited to no access to mental health resources. Quantitative findings revealed that Ottawa’s marginalized populations report life long, frequent, and heavy cannabis use with the average participant meeting the cut off for severe cannabis use dependency, anxiety, and depression. A notable proportion of participants also screened positive for psychosis. The findings also demonstrate that daily cannabis use was negatively correlated with self-reported physical health and depression, and positively correlated with self-reported anxiety. Overall, the dissertation findings highlight the utility of CBPR to intervene on substance use, and to illuminate the specific cannabis use and related health experiences of Ottawa’s vulnerable and most marginalized populations.enAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/Substance Use HealthCommunity Based Participatory ResearchHealth EquityThesis