Do-It-Yourself medicine? The impact of light cannabis liberalization on prescription drugs
In this paper, published in the Journal of Health Economics, Vincenzo Carrieri (Magna Grecia University, RWI, IZA), Leonardo Madio (dSEA UNIPD, CESifo) and Francesco Principe (Erasmus School of Economics Rotterdam) explore the unintended liberalization of light cannabis that occurred in Italy in December 2016 by means of a legislative gap.
The cannabis market has gained momentum worldwide. Low-strength versions of cannabis such as hemp (or industrial hemp), rich in cannabidiol (CBD), have blossomed in the form of herbal cannabis, lotions, extracts, and candies. For its similarities to medical marijuana, which requires a doctor's prescription, these are often advertised as effective to treat pain relief, anxiety, and sleep disorders. Notwithstanding, little is known about the impact of this new market, which has raised several concerns in the US and UE on the possible health risks associated with these products. We ask the following question:
Does the availability of cannabis-derived products suitable for self-medication lead to a reduction in the consumption of existing drugs?
To this end, we studied a unique case of unintended liberalization that occurred in Italy in 2017 when light cannabis was unexpectedly allowed to circulate in the market. Specifically, in December 2016, the Italian government passed a law (Law 242/16) to facilitate the cultivation of industrial hemp in Italy. Due to a loophole in the legislation, the law rendered “not illegal” the large-scale commercialization of the cannabis flower (light cannabis) in the absence of psychotropic effects (0.2−0.6% THC). Given the unintended scope of the liberalization, the product was sold as a collector’s item and not as a product suitable for human consumption, since May 2017.
We exploited the territorial heterogeneity in the access to the product in the very short period after the policy (May 2017 to February 2018) using monthly data on local availability of light cannabis shops and prescription drugs from 106 Italian provinces. In the analysis, we considered those prescription drugs for which medical marijuana (but not light cannabis) can be effective. These included opioids, anxiolytics, sedatives, anti-migraines, anti-epileptics, antipsychotics, and anti-depressants.
In a staggered difference-in-difference framework we found that the local availability of light cannabis led to a significant decrease in the number of dispensed boxes of anxiolytics by approximately 11.5%, a reduction of dispensed sedatives by 10%, and a reduction of dispensed antipsychotics by 4.8%. More nuanced but still significant effects are found for anti-epileptics (-1.5%), anti-depressants (-1.2%), opioids (-1.2%), anti-migraines (-1%). Substitutional patterns were more accentuated, starting from the third month after the introduction of the product in the local market. Indeed, in the short window considered, Italians started abandoning traditional drugs when light cannabis became largely available and suggest that their experience with the product outperformed conventional medicine.
These results are compatible with a self-medication hypothesis, that is, the adoption of risky behaviors to seek quality of life improvements and relief. Indeed, the large-scale accessibility to the new product, which was advertised as a relaxant one, induced some patients to abandon traditional medicine to seek relief. Self-medication was possible as the product was neither suitable for medical purposes nor was allowed to be consumed. This rendered less likely that the substitutional patterns we observed were driven by medical advice.
