Changes in the unregulated opioid drug supply during income assistance payment weeks in Vancouver, Canada: An exploratory analysis.

Background: Increased drug-related harms, including overdoses (poisonings), have been reported in the days around income assistance payments, yet little is known about changes in the unregulated drug supply during this time. In this exploratory analysis, we investigated whether changes in the unregulated opioid drug supply are associated with income assistance payment weeks.

Methods: Using data from drug checking services in Vancouver, BC, we conducted modified Poisson and linear regression models to examine the association between income assistance payment weeks and three key outcomes: (1) proportion of fentanyl positivity among expected opioid samples, (2) fentanyl concentration among fentanyl-positive expected opioid samples, and (3) proportion of benzodiazepine positivity among expected opioid samples.