Drug Use Burden and Enforcement Indicators in Nigeria: A Retrospective Ecological Analysis.

Background: Nigeria faces a substantial burden of illicit drug use alongside intensified enforcement activity. However, the geographic correspondence between enforcement indicators and population-level drug use burden remains poorly characterised. This study provides an ecological assessment of enforcement-burden alignment in Nigeria and introduces a Total Seizure-to-Any-Drug-User Ratio (TSUR) as a policy-relevant surveillance metric. Methodology: We conducted a retrospective ecological analysis of Nigeria's six geopolitical zones. Drug use burden was obtained from the 2018 Drug Use in Nigeria survey; seizure, arrest, and conviction data were extracted from National Drug Law Enforcement Agency (NDLEA) reports (2021-2022). We calculated a Total Seizure-to-Any-Drug-User Ratio (TSUR; kg seized per 1,000 estimated past-year users) using 2018 survey denominators and 2021-2022 NDLEA seizure totals. Associations were assessed using Spearman's rank correlation (n = 6 zones). To evaluate robustness to temporal mismatch, we conducted sensitivity analyses assuming ±10-20% changes in zonal prevalence. Results: Past-year drug use prevalence ranged from 10.0% to 22.4% across zones. National seizures increased substantially between 2021 and 2022 and were dominated by cannabis by weight. TSUR varied markedly across geopolitical zones (<5 kg to >300 kg per 1,000 users), indicating substantial geographic differences in seizure intensity relative to the 2018 baseline distribution of drug users. Zone-level correlations between seizure weight and estimated users were positive but statistically unstable, given the small number of aggregate units. Conclusions: Marked regional variation exists in both drug use burden and enforcement activity across Nigeria. Using a historical demand-side baseline and subsequent enforcement indicators, this analysis demonstrates only partial geographic concordance between seizures and estimated user burden. The TSUR provides a transparent, scalable metric for contextualising enforcement activity alongside epidemiological estimates in data-constrained settings, when interpreted cautiously.