The effects of using answer sheets on reported drug use and data quality in a classroom survey: A cluster-randomized study

Does recreational cannabis legalization change cannabis use patterns? Evidence from secondary school students in Uruguay

BACKGROUND AND AIMS

In 2013, Uruguay became the first country to legalize and regulate the production and distribution of cannabis for recreational use. We measured whether Uruguay's non-commercial model of recreational cannabis legalization was associated with changes in the prevalence of risky and frequent cannabis use among secondary school students.

DESIGN

We used data from repeated cross-sectional surveys of secondary students in Uruguay and Chile (2007-2018). Using a difference-in-difference approach, we evaluated changes in the prevalence of past-year, past-month, any risky and frequent cannabis use following enactment (2014) and implementation (2016) of cannabis legalization among the full sample of secondary students and among students who reported past-year/month use. We examined changes separately for students ages 12 to 17, and students for whom cannabis became legally accessible, ages 18 to 21.

SETTING

Uruguay and Chile (2007-2018).

PARTICIPANTS

Secondary school students in 8th, 10th and 12th grade (n = 204 730).

MEASUREMENTS

Past-year and past-month cannabis use; any risky cannabis use measured with the Cannabis Abuse Screening Test (CAST); and frequent cannabis use (10+ days in the past-month).

FINDINGS

We found a decrease in past-year and past-month use following enactment or implementation. Among students ages 18 to 21, post-enactment, we observed a transitory increase in 2014 that decreased thereafter for: any risky use among those who reported past-year use (prevalence difference [PD] = 13.5%; 95% CI: 2.0, 24.9), frequent use in the full sample (PD = 4.5%; 95% CI: 1.0, 8.1), and frequent use among those who reported past-month use (PD = 16.8%; 95% CI: 1.9, 31.8).

CONCLUSION

The legalization of recreational cannabis in Uruguay was not associated with overall increases in either past-year/past-month cannabis use or with multi-year changes in any risky and frequent cannabis use among young people.

Trends in the sequence of initiation of alcohol, tobacco, and marijuana use among adolescents in Argentina and Chile from 2001 to 2017

BACKGROUND

Variation in drug policies, norms, and substance use over time and across countries may affect the normative sequences of adolescent substance use initiation. We estimated relative and absolute time-varying associations between prior alcohol and tobacco use and adolescent marijuana initiation in Argentina and Chile. Relative measures quantify the magnitude of the associations, whereas absolute measures quantify excess risk.

METHODS

We analyzed repeated, cross-sectional survey data from the National Surveys on Drug Use Among Secondary School Students in Argentina (2001-2014) and Chile (2001-2017). Participants included 8th, 10th, and 12th grade students (N = 680,156). Linear regression models described trends over time in the average age of first use of alcohol, tobacco, and marijuana. Logistic regression models were used to estimate time-varying risk ratios and risk differences of the associations between prior alcohol and tobacco use and current-year marijuana initiation.

RESULTS

Average age of marijuana initiation increased and then decreased in Argentina and declined in Chile. In both countries, the relative associations between prior tobacco use and marijuana initiation weakened amid declining rates of tobacco use; e.g., in Argentina, the risk ratio was 19.9 (95% CI: 9.0-30.8) in 2001 and 11.6 (95% CI: 9.0-13.2) in 2014. The relative association between prior alcohol use and marijuana initiation weakened Chile, but not in Argentina. On the contrary, risk differences (RD) increased substantially across both relationships and countries, e.g., in Argentina, the RD for tobacco was 3% (95% CI: 0.02-0.03) in 2001 and 12% (95% CI: 0.11-0.13) in 2014.

CONCLUSION

Diverging trends in risk ratios and risk differences highlight the utility of examining multiple measures of association. Variation in the strength of the associations over time and place suggests the influence of environmental factors. Increasing risk differences indicate alcohol and tobacco use may be important targets for interventions to reduce adolescent marijuana use.

Parental protective and risk factors regarding cannabis use in adolescence: A national sample from the Chilean school population

Background: Research has increased our understanding of the parental factors associated with the initiation and development of cannabis use disorder in adolescents, but few studies about this have been performed in middle- or low-income countries.

Objective: First, to examine whether perceived past parental drug use, parental monitoring, and attitude toward adolescent cannabis use are associated with general and problematic cannabis use in Chilean adolescents. Second, to explore whether perceived past parental drug use weakens the associations of protective factors with general and problematic adolescent cannabis use.

Methods: Regression analyses were performed on cross-sectional data from a multistage probabilistic sample stratified by clusters (municipalities, school and grade) of 43,060 students (47% male, mean age 15.5 years) from grades 8 to 12, which was collected from the Chilean National School Survey on Drug Use (2013).

Results: Perceived past parental drug use increased the likelihood of adolescent cannabis use in general, but not its problematic use. Parental monitoring of adolescents' whereabouts and parental opposition to adolescent cannabis use decreased the likelihood of adolescent cannabis use in general, as well as problematic use. Perceived past parental drug use only interacted with parental monitoring of school activities.

Conclusions: In line with research from the United States, the Netherlands and Spain, parental monitoring of adolescents' whereabouts and a strong parental opposition to cannabis use appear to be protective factors, irrespective of past parental use. However, the effectiveness of monitoring adolescents' school activities seems to decrease when parents are perceived as having used drugs in the past.

Sex differences in nonmedical prescription tranquilizer and stimulant use trends among secondary school students in Argentina, Chile, and Uruguay

BACKGROUND

Little is known about recent nonmedical prescription tranquilizer and stimulant use trends in Latin America. We tested whether recent trends among students in three South American countries differed by sex over time.

METHODS

Three countries independently collected National School Students Survey on Drugs. Students in 8th, 10th, and 12th grades were sampled in Argentina (2007-2014, N = 328,202), Chile (2007-2015, N = 136,379), and Uruguay (2007-2016, N = 32,371). Weighted linear regression models predicted the prevalences and trends over time of past-year nonmedical tranquilizer and stimulant use by country, and tested whether trends differed by sex, adjusting for school type and grade.

RESULTS

In Argentina from 2007 to 2014, past-year nonmedical prescription tranquilizer (girls: 2.8 to 2.6%, boys: 2.5 to 2.3%) and stimulant (girls: 1.7 to 1.3%, boys: 1.9 to 1.5%) use trends did not differ by sex. In Chile from 2007 to 2015, nonmedical prescription tranquilizer use trends significantly differed comparing girls (3.9 to 10%) with boys (3.2 to 6.9%); stimulant use trends did not differ comparing girls (1.6 to 2.0%) with boys (2.0 to 1.3%). In Uruguay from 2007 to 2014 and 2014-2016, past-year nonmedical prescription tranquilizer (girls: 5.1 to 6.6%; boys: 2.8 to 4.2%) and stimulant (girls: 1.8 to 0.7%; boys: 1.8 to 0.7%) use trends did not differ by sex.

CONCLUSIONS

Trends of nonmedical prescription tranquilizer use recently increased in Chile and Uruguay, widening by sex over time in Chile only. The drivers of increasing tranquilizer use among girls in Chile and Uruguay merit further investigation.