The impact of cannabis policy changes on substance use among adolescents: evidence from Europe
(E. Benedetti, G. Resce, M. Scalese, P. Brunori e S. Molinaro)
Cannabis is one of the most widely used illegal drugs in the world. In Europe, despite some evidence of decreasing trends, cannabis use level remains high (World Drug Report, 2017). Over the last 20 years, there have been many policy changes in Europe aimed at influencing cannabis supply and demand. EMCDDA (2017) classified the policy changes occurred in the various European countries into four broad cathegories: those reducing the maximum prison sentence, those removing the prison sentences for minor offences, those increasing the non-prison penalty, those facilitating the closure of a minor case.
The aim of this research is to analyze the impact of each category of drug policy on the diffusion of cannabis use among adolescents. Data were drawn from the ESPAD trend database, which covers a period of 20 years in more than 40 European countries. ESPAD is a multinational survey project conducted every 4 years collecting comparable data on substance use among 16-year-old students.
Following the theory of impact evaluation, we considered a specific policy change as the treatment, and countries subject to the policy as the treated. We also included a control group, comprising countries that did not experience any policy modification in the same time interval. We analyzed how policy changes affected the availability of cannabis and impacted on adolescent users, focusing on three groups of consumers: experimental (those having tried it at least once in the lifetime) recent (those who report using in the past month) and frequent users (20 or more occasions per month). Preliminary results show that there are specific policy changes able to affect some types of cannabis consumers as well as the diffusion of other licit and illicit substances.