Changes in use and availability of cannabis among adolescents over last two decades. Situation in Poland and selected European countries

Introduction
The aim of the article is to analyse prevalence of use and availability of cannabis (marijuana and hashish) by adolescents in the last 20 years in Poland and compare the results with those obtained in selected European countries (Czech Republic, France, Finland and Ukraine).

Material and methods
Data from the ESPAD study were used. Trends analyses include data from measurements obtained in 1995, 1999, 2003, 2007, 2011 and 2015.

Results
Over the last 20 years a threefold increase in prevalence of cannabis use among adolescents is observed in Poland. Regarding experimental use, this is the highest increase in prevalence compared to reference countries. During the last two decades the perceived availability of marijuana and hashish has doubled in Poland. In 2015, availability was assessed at a similar level as in France. Recently, in all countries there has been a decrease noticed in the percentage of respondents claiming that the availability of cannabis is easy. In Czech Republic this trend was noted even earlier since 2007.

Discussion
Changes in Polish drug policy in the last 20 years can be treated as restrictive, aimed at limiting of use. However, the prevalence of cannabis use among adolescents has increased. On the other hand, in the Czech Republic, where liberal legislative changes were implemented in 2010, a decrease in the prevalence of use has been observed since 2007.

Conclusions
Legal instruments regulating the supply and demand of drugs may have less impact on shaping the prevalence than psychosocial factors identified at the individual user level, such as knowledge on places where you can easily get substances or drug use by friends and significant others.