Preventing tobacco use from the start: Short- and medium-term impacts on the youth.

Adolescent substance use is a persistent global problem and a challenge for society and the public health authorities. In this paper we investigate the impact of a prevention-oriented policy implemented in Icelandic secondary schools from 1997 to 2002 (the "Drug-free Iceland" programme) on country-level smoking rates on the youth. Using a panel data source spanning from 1985 to 2010 and composed both by Iceland and a set of countries where such a type of policy was absent, we apply the Synthetic Control Method to construct the counterfactual of Iceland. Comparing Iceland with this counterfactual, we estimate the effect of the intervention on those aged 15 to 19 -who were the main target of the policy-, during the years of implementation of the programme, and follow their smoking prevalence rates overtime until 2010, when they became adults (25 to 29-years old). Our results show that the intervention reduced youth smoking prevalence on the targeted groups that lasted at least until they became adults. We also find evidence of externalities in the age groups adjacent to those directly targeted by the policy. The results differ by gender, with the impact on females being more marked.