FRANÇAIS :
Alors que le cannabis reste interdit au niveau fédéral, dix États américains sur 50, ainsi que Washington DC, ont, depuis 2012, légalisé la culture, la vente, la détention et la consommation de cette substance à des fins récréatives à partir de 21 ans.
Par ailleurs, 33 États américains en autorisent déjà l'usage « thérapeutique ».
Cette note, initialement publiée en mars 2017, vient d'être actualisée à partir des données disponibles les plus récentes. Elle décrit les modèles de régulation mis en place depuis 2014 par les différents États, en soulignant leurs convergences et leurs disparités. Par ailleurs, elle rend également compte des premiers effets de ces réformes en termes de développement du marché, d'impact sur le marché noir mais aussi en matière de santé publique, en particulier dans les deux premiers États américains qui ont entrepris de réguler le marché du cannabis : le Colorado et l'État de Washington.

ENGLISH:
This memo describes the regulatory models that have been implemented since 2014 in the American states that have legalised cannabis, highlighting their differences and similarities. It also discusses the reform processes and common features of states that have legalised cannabis for medical and recreational use.
After five full years of reform in Colorado and Washington State (2014-2018), first outcomes can be reported - although it is not clear whether they are directly attributable to cannabis being legalised. The most significant effects relate to the quick and large-scale industrial expansion of the cannabis supply chain. However, this economic boom has also seen the emergence of three public health concerns:
- The substance is now aimed at all population profiles, from people who have never tried it to regular users and from young people to seniors. The increase in supply and its diversification have increased the incentives to use it, which is only made worse by marketing strategies emphasising cannabis' "therapeutic virtues" or its dimension of socialisation.
- The increase in the number of emergency calls and hospitalisations following acute intoxication highlights the difficulty of effectively regulating substances put on the market (particularly in terms of the concentration of active ingredients). At the same time, cannabis-related treatment demands have declined.
- The decline in both the perceived dangerousness of cannabis and retail prices have led to it becoming more accessible and the substance being "normalised" which, according to public health stakeholders, could ultimately increase the risks and harm associated with its use (particularly among the younger generation).