Economic Opportunity and Opioid Regulation: the Case of Codeine in France

This paper empirically assesses the impact of laws restricting access to opioid painkillers and shows how local economic conditions matter for the magnitude of responses to these policies. By using a di˙erence in di˙erences (DiD) approach, I first estimate the causal impact of a new regulation that forbids over-the-counter (OTC) sales of Codeine-containing drugs. I then exploit a triple di˙erence (TD) strategy to evaluate possible heterogeneous responses across French departments. Using OpenHealth monthly data on Codeine product sales in 2017 for the 94 de-partments of Metropolitan France allows me to verify the parallel trend assumption validity. I find that the new law proved e˙ective in reducing Codeine consump-tion, but departments in economic disadvantage exhibit smaller decreases in con-sumption following its implementation. Hence, high-poverty departments are more ‘regulatory-inelastic'. This shows that demand-side factors can contribute to ampli-fying or hindering the e˙ect of supply-side interventions. Substitution e˙ect analysis finds an increase in non-opioid analgesic use after the new law in wealthy depart-ments relative to poor departments, but no significant substitution towards the black market. Results suggest that increased barriers to access should move in parallel with additional measures addressing the most deprived local communities.