Impact of environmental factors on marijuana use in 11 European countries

Aim

To investigate the association between environmental factors (perceived availability of marijuana, perceived use among friends and siblings, use of alcohol and tobacco, family structure, parental control, school performance) and lifetime prevalence and frequent and early marijuana use in high school students.

Methods

We used self-reported data from 15-16 years old participants of the 2003 European School Survey Project on Alcohol and Other Drugs (ESPAD) conducted in 11 countries: Denmark, Estonia, Norway, Croatia, Slovenia, Germany, Switzerland, Bulgaria, Czech Republic, Russian Federation, and Ukraine. Multivariate logistic regression was used for data analysis.

Results

Countries varied according to lifetime prevalence (8.7%-47.8%) and frequent (8.7%-23.9%) and early (3.0%-13.0%) marijuana use. Daily tobacco smoking was most strongly associated with lifetime marijuana use for boys in 7 and for girls in 5 countries, with highest odds ratio (OR, 95% and confidence interval – CI) for boys in Denmark (OR, 13.52; 95% CI, 8.16-22.4), and for girls in the Czech Republic (OR, 21.21; 95% CI, 12.99-34.62). Perceived marijuana availability was most strongly associated with frequent marijuana use for boys in 4 countries (highest in Slovenia: OR, 19.28; 95% CI, 6.52-57.02) and girls in 5 (highest in Slovenia: OR, 19.05; 95% CI, 5.18-70.04). Perceived use of marijuana among friends was most strongly associated with frequent marijuana use in 5 countries, both for boys (highest in Norway: OR, 23.91; 95% CI, 4.16-137.48) and girls (highest in Denmark: OR, 75.42; 95% CI, 13.11-433.90). Perceived use of marijuana among friends was most strongly associated with early marijuana use in 8 countries for boys (highest in Norway: OR, 54.03; 95% CI, 3.34-875.19) and 3 countries for girls (highest in Denmark: OR, 7.29; 95%CI, 1.77-30.12).

Conclusion

In each country, marijuana use was associated with similar factors, regardless of marijuana use prevalence in that country.The influence of peer group and perceived availability of marijuana seemed more important than parental control and family structure.Following tobacco and alcohol, cannabis continues to be the psychoactive substance most commonly used by school children (1). Epidemiological research during the past 10 years suggests that regular use of cannabis during adolescence and into adulthood can have adverse effects. The most probable adverse effects include a dependence syndrome, increased risk of motor vehicle accidents, impaired respiratory function, risk of cardiovascular disease, and adverse effects on adolescents’ psychosocial development and mental health (2). There is substantial evidence that alcohol, tobacco, and cannabis dependence problems surface more quickly when use of these drugs starts before adulthood (3). Early and regular cannabis use in adolescence predicts an increased risk of cannabis dependence, which in turn predicts an increased risk of using other illicit drugs (4). Frequent cannabis use in late adolescence and early adulthood is associated with a range of adverse outcomes in later life (5). Adolescent substance use is directly affected by peer influence (6), while parent-family connectedness is protective for health risk behavior (7). It was found that authoritative parenting style leads to better adolescent school performance and stronger school engagement (8), while parental monitoring, open parent-child communication, supervision, and high quality of the parent-child relationship deter involvement in high-risk behavior (9). Both parents and peers can have strong influences on adolescents, depending on the arena of influence. Parents are particularly important for future life plans, while peers are most important for involvement in illicit drug use (10). However, for drug use itself, there are different patterns of influence depending upon the stage of drug involvement. Peers are especially important for initiation into marijuana use, while parental factors gain in importance in the transition from marijuana use to the use of other illicit drugs (10). The 2003 European School Survey Project on Alcohol and Other Drugs (ESPAD) Report by Hibell et al found that association between adolescent substance use and family background was complex and dependent upon the type of substance, element of family background, and the country of study (11). Generally, the strongest correlates of substance use by adolescent students were going out most evenings, substance use by peers and siblings, and antisocial behavior (12).In this study, we investigated the influence of contextual factors on lifetime marijuana use, frequent marijuana use (10 times or more in the lifetime), and early onset of marijuana use (13 years or younger) by sex in 11 European countries.