Spatial patterns of arrests, police assault and addiction treatment center locations in Tijuana, Mexico

Aims: In the context of a public health-oriented drug policy reform in Mexico, we assessed the spatial distribution of police encounters among people who inject drugs (PWID) in Tijuana, determined the association between these encounters and the location of addiction treatment centers and explored the association between police encounters and treatment access.

Design: Geographically weighted regression (GWR) and logistic regression analysis using prospective spatial data from a community-recruited cohort of PWID in Tijuana and official geographical arrest data from the Tijuana Municipal Police Department.

Setting: Tijuana, Mexico.

Participants: A total of 608 participants (median age 37; 28.4% female) in the prospective Proyecto El Cuete cohort study recruited between January and December 2011.

Measurements: We compared the mean distance of police encounters and a randomly distributed set of events to treatment centers. GWR was undertaken to model the spatial relationship between police interactions and treatment centers. Logistic regression analysis was used to investigate factors associated with reporting police interactions.

Findings: During the study period, 27.5% of police encounters occurred within 500 m of treatment centers. The GWR model suggested spatial correlation between encounters and treatment centers (global R(2) = 0.53). Reporting a need for addiction treatment was associated with reporting arrest and police assault [adjusted odds ratio = 2.74, 95% confidence interval (CI) = 1.25-6.02, P = 0.012].

Conclusions: A geospatial analysis suggests that, in Mexico, people who inject drugs are at greater risk of being a victim of police violence if they consider themselves in need of addiction treatment, and their interactions with police appear to be more frequent around treatment centers.