Adolescence is a period in which many youth initiate the use of psychoactive substances. To illustrate, between ages 15 and 21, a sharp increase is seen in the incidence of alcohol, tobacco, and cannabis use, with estimates of, respectively, 90, 70, and 25–50 percent in American and European 21-year-olds [1]. Increased levels of substance use are associated with problems later in life, including poor educational performance, health problems and substance use disorders [2–5].
