Global health. The current scenario and future perspectives

213 while the dashed lines represent countries where sanctions were increased. Simply put, visually there is no evidence of a change in the expected direction in either situation, which leads the authors to conclude that moderate changes in laws regarding cannabis use are not necessarily associated with changes in prevalence of cannabis use. Figure 4: Trend in past-year prevalence of cannabis use among individuals aged 15-34 before and after penal change. Source: Hughes, B., Matias, J. & Griffiths, P. (2018). Inconsistencies in the assumptions linking punitive sanctions and use of cannabis and new psychoactive substances in Europe. Addiction, 113(12), 2155-2157 A second legislative change is related to the approval of laws on use of cannabis for therapeutic purposes. This situation generated a hypothesis in the sence that the discussion and approval of laws on therapeutic use of cannabis would decrease the perception of risk and have an impact on increased consumption. To analyze this, we will look at the United States, where this legislation has been more widespread. The article by Devora S. Hasin et al., published in The Lancet/Psychiatry in 2015 (Hasin et al., 2015), analyzes this situation using past-month prevalence of marijuana use as an indicator, obtained from studies conducted under the Monitoring the Future (MTF) program (National Institutes of Health, 2021). This is an annual survey conducted since 1975 among students in grades 8 th , 10 th and 12 th in the United States; i.e., ages ranging from 13 to 14, 15 to 16 and 17 to 18 years old (modal values for each grade level). The publication considered studies from 1991 to 2014 with a total accumulated sample size of 1,089,270 students.