Prices and Policies in Opioid Markets [pdf]
hoover.org
hoover.org
First, comparing whites and blacks is misleading, you'd want to compare wealthy vs. poor consumers of the drug. Second, lumping 'opiods' together makes little sense when fentanyl is so different in activity-per-gram, and cost-of-production relative to oxy, heroin, and morphine. Third, overdoses are often related to opiate addicts using drugs of varying purity, which is what is found on illegal markets (plus other confounders like suicide attempts, recovering addicts who've lost tolerance falling off the wagon, etc.).
Just more evidence that Chicago School Economics is just artful propaganda financed by oligarchs to promote further accumulation of wealth in the hands of the few.
The price of illicit opioids was decreasing at the same time the cost of prescription opioids was increasing. Illicit opioids are a substitution product for prescription opioids for many consumers, so they adjusted their consumption to a more dangerous but cheaper product to fit budgetary constraints.