Identifying Pathways between Socioeconomic Factors and Overdose: A Systematic Realist Synthesis

BACKGROUND: Employing a realist approach, this review aims to describe how direct and indirect socioeconomic elements lead to overdose in people who use opioids. METHODS: We conducted a systematic realist review to understand the underlying structures and processes connecting socioeconomic elements to overdose. Empirical studies published between 2004 and 2019 were identified through six electronic databases (MEDLINE, EMBASE, PyschINFO, CINAHL, Web of Science and Google Scholar), grey literature searches, and manual citation searches. We conducted title, abstract, and full-text screening. We thematically analyzed and synthesized extracted data and performed a quality and relevance appraisal (i.e., assessing the quality of evidence for mechanisms). RESULTS: A total of 55 studies were included in this review. Eight overlapping dimensions with direct and indirect linkages to socioeconomic wellbeing were identified: income and poverty, employment, housing and drug use settings, social networks and norms, criminal justice involvement, gender-based dynamics, acute life events, and stigma. Socioeconomic determinants shaped overdose risk through intermediate outcomes and a range of intersecting material (e.g., deprivation), normative (e.g., fear of criminalization), and bio-psychosocial pathways (e.g., psychological distress or mental illness). A majority of evidence suggested that conditions of socioeconomic adversity trigger drug use as a means to cope with exacerbated mental health concerns or psychological distress (bio-psychosocial pathways), leading to overdose. Supportive evidence for this mechanism was found across all identified socioeconomic dimensions. CONCLUSIONS: Findings point to the need to address the socioeconomic production of overdose risk, with additional emphasis on the pathways and mechanisms linking socioeconomic elements to overdose outcomes.