1. In a nationally representative survey of American adolescents, there was a fivefold increase in prevalence of lifetime abstinence from substance use among high school seniors.
2. Prevalence of lifetime abstinence from cigarettes and alcohol increased most drastically, whereas rates of marijuana and other substance use have remained more steady.
Evidence Rating Level: 2 (Good)
Study Rundown: Substance use is an important modifiable health behavior, and previous studies have focused on use of individual substances. In this cross-sectional study, researchers sought to characterize trends in substance nonuse among adolescents by analyzing responses to the Monitoring the Future Project (MTF), a survey of nationally representative samples of 8th-, 10th-, and 12th-grade students between 1976 and 2014. Prevalence of lifetime abstinence from substance use among high school seniors has risen from 5% in 1976 to 26% in 2014, with similar trends among 8th- and 10th-grade students. Abstinence from cigarettes and alcohol increased dramatically during the study period, while abstinence of marijuana and other illicit substances increased only slightly and, in the case of marijuana, have fallen from peak levels in the 1990s. Students who were male, African American, or reported higher levels of religious involvement were significantly more likely to report lifetime abstinence. Lower odds of reporting lifetime abstinence were noted among students with low grade point average, past-month truancy, employment during the school year, and living in a single-parent household.
These findings are limited by self report bias. True prevalence may be underestimated because adolescents who were not in school to take the survey and those who were missing data for any substance were excluded from analysis. Nonetheless, the study is strengthened by its large, nationally representative sample of high school students. For physicians, these results highlight the importance of identifying and discussing the use of marijuana and other substances with adolescents and parents.
Relevant reading: Adolescent Substance Abuse: Risk Factors and Protective Factors
In-Depth [cross-sectional study]: Researchers used 1976 to 2014 data from the MTF, which surveys approximately 51 000 8th-, 10th-, and 12th- grade students in hundreds of schools nationwide each year regarding lifetime and current (last 30-day) use of cigarettes, alcohol, marijuana, and other substances. Students who were absent from school on the day of the survey, and surveys that indicate invalid responding were excluded from analyses. Adjusted odds ratios (aORs) for lifetime abstinence from all substance use were calculated using 2014 data for several variables including sex, race, parents in household, parental education, school type, truancy, grade point average, religiosity, and hours worked per week.
The percentage of 12th-graders reporting lifetime abstinence from substance use rose from 5% in 1976 to 26% in 2014. No current (past 30 day) substance use was reported by 23% of seniors in 1976, which rose to 52% in 2014. While prevalence of alcohol use and cigarette use followed these trends, lifetime abstinence from marijuana among 12th-graders rose only slightly from 47% in 1976 to 56% in 2014, with a peak of 67% in 1992. After controlling for all other variables, those associated with higher odds of reporting lifetime abstinence included male gender (aOR: 1.25; 95%CI: 1.10-1.42), African American race (aOR: 1.53; 95%CI: 1.27-1.85) or other race category (aOR: 1.23; 95%CI: 1.02-1.47), and higher levels of religious involvement (aOR: 1.41; 95%CI: 1.21-1.51). Lower odds of reporting lifetime abstinence was associated with living in a single parent household (aOR: 0.67; 95%CI: 0.59-0.76), low grade point average (aOR: 0.63; 95%CI: 0.52-0.75), and higher hours worked per week (aOR: 0.87; 95%CI: 0.84-0.90).
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