Finally, although our sample was representative of the Finnish population, the findings may not be fully generalizable to other populations. The Finnish educational system is among the most equal ones globally with very modest between-school variation among Finnish students (Organisation for Economic Cooperation and Development, 2007). Alcohol use and smoking are also relatively common in Finnish adolescents from all socioeconomic backgrounds (Currie et al., 2012). The present study thus clearly extends previous research which is almost entirely based on samples from the United States.
