Looking through the cracks: vulnerabilities and deprivation in the Brazilian open drug scenes

BACKGROUND: Cocaine use is increasing worldwide, and Brazil, located along major transatlantic trafficking routes, has experienced widespread availability of low-cost crack, which circulates predominantly in open drug scenes (ODS). ODS are public spaces where drug use, purchase, sale, and social interaction converge. While national surveys have identified these settings as central to crack use, their social, structural, and spatial characteristics remain poorly understood. This study offers a nationwide description of Brazilian ODS, providing empirical evidence that can inform targeted, context-sensitive interventions. METHODS: We analyzed 3,787 ethnographic field notes from the 2014 Brazilian Crack Survey, a unique nationwide study describing the lived environments of ODS. Using Structural Topic Modeling with document-level covariates (location, weekday, and shift of observation), we identified recurring social, spatial, and behavioral patterns. Intertopic correlations guided the interpretation of broader thematic domains, and Topic Share statistics measured each topic's prevalence across scenes. RESULTS: ODS exhibited consistent signs of structural vulnerability, including lack of infrastructure, unstable housing, drug-use patterns, and uneven law enforcement dynamics. High-prevalence topics included crack paraphernalia sharing (TS = 24.83%) and polydrug use (TS = 15.95%). Areas marked by blatant poverty (TS = 15.71%), whether related to favelas and under-bridge sites (TS = 12.64%) or a significant presence of minors trafficking or using crack (TS = 3.07%), were typical of the city outskirts. In contrast, ODS in commercial zones (TS = 14.07%) involved unhoused populations (TS = 5.13%) and a "cat-and-mouse" dynamic among dealers, people who use crack, and police (TS = 8.94%). Hidden drug use (TS = 13.36%) was associated with social stigma (TS = 7.78%) and fear of law enforcement (TS = 5.58%). CONCLUSION: Brazilian ODS share a foundation of structural deprivation but vary substantially in their socioterritorial configurations. Recognizing this heterogeneity is essential for designing interventions that account for how place-specific infrastructures, stigma gradients, and local regulatory dynamics shape drug-use environments. These findings provide empirical support for public health and social policies that address the diverse realities of ODS across Brazil.