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.

Investigating how perceived risk and availability of marijuana relate to marijuana use among adolescents in Argentina, Chile, and Uruguay over time.

AIMS: Amid changing marijuana policies in the Southern Cone, we examined relationships between marijuana-related risk factors and marijuana use among adolescents in Argentina, Chile, and Uruguay from 2001 to 2016. METHODS: Using cross-sectional surveys from 8th, 10th, and 12th graders and weighted time-varying effect models, we estimated associations between perceived risk (no/low risk versus moderate/great risk) and perceived availability (easy/very easy versus difficult/very difficult/not able to obtain) of marijuana, and any past-month marijuana use. RESULTS: In all countries, marijuana use increased over time and adolescents who perceived no/low risk and easy availability had higher odds of use. In Argentina, the bivariate risk/use association weakened from 2001 (OR = 15.24, 95%CI = 9.63, 24.12) to 2004 [OR = 3.86 (2.72, 5.48)] and strengthened until 2011 [OR = 8.22 (7.56, 10.30)]; the availability/use association strengthened from 2005 [OR = 5.32 (4.05, 6.98)] to 2009 [OR = 20.77 (15.57, 27.70)] and weakened until 2014 [OR = 11.00 (9.11, 13.27)]. In Chile, the risk/use association weakened from 2001 [OR = 7.22 (6.57, 7.95)] to 2015 [OR = 5.58 (4.82, 6.48)]; the availability/use association weakened from 2001 [OR = 5.92 (4.96, 7.06)] to 2015 [OR = 4.10 (3.15, 5.34)]. In Uruguay, the risk/use association weakened from 2003 [OR = 34.22 (22.76, 51.46)] to 2016 [OR = 6.23 (4.96, 7.83)]; the availability/use association weakened from 2005 [OR = 29.13 (13.39, 63.39) to 2007 [OR = 9.42 (3.85, 23.07)], and strengthened until 2016 [OR = 22.68 (12.03, 42.76)]. CONCLUSIONS: Overall, the association between risk and use weakened in all countries, suggesting risk perceptions became a weaker determinant of marijuana use. Perceived availability remained strongly associated with use and may become an increasingly important driver of use (particularly in Uruguay and Argentina).