The likelihood an adolescent will try marijuana begins around age 11 and rises steadily until 16, then decreases before hitting another peak around 18.
“Many existing marijuana intervention programs target students age 15 and older,” says Xinguang (Jim) Chen, professor of epidemiology at the University of Florida. “Our findings demonstrate the need to start drug education much earlier, in the fourth or fifth grade. This gives us an opportunity to make a preemptive strike before they actually start using marijuana.”
As medical marijuana laws are passed in more states, there is concern among some experts that adolescents may view marijuana as a substance that can be used safely by anyone, regardless of whether or not it is part of a treatment plan under a physician’s supervision.
Using marijuana at a young age could put adolescents at risk for cognitive problems, according to the National Institute on Drug Abuse. Teens who use marijuana may have impaired brain development and lower IQ. They may receive lower grades and are more likely to drop out of high school.
Published in the American Journal of Drug and Alcohol Abuse, the new study was designed to learn when adolescents are most at risk for starting marijuana use. It is one of the first to examine the likelihood of marijuana initiation as a function of age and used a method called survival analysis that is more sensitive to fluctuations across age groups, Chen says.
Researchers analyzed data from the 2013 National Survey on Drug Use and Health, a nationwide cross-sectional survey including approximately 27,000 respondents ages 12 to 21, sponsored by the Substance Abuse and Mental Health Services Administration.
The findings show the likelihood that adolescents would start using marijuana climbed steadily starting at age 11, reaching a first peak at age 16.
But there was a surprise: a dip in the possibility that teens would start using marijuana at age 17. The team theorizes that at this age, many teens are focused on improving grades and preparing for college entrance exams, which could pull their attention away from experimenting with drugs.
The finding may offer another approach for developing interventions, Chen says.
“Increasing adolescents’ academic responsibilities and placing more emphasis on education could be one way to postpone drug use initiation, ultimately preventing drug use.”
The likelihood of marijuana initiation rebounded at age 18 for a second peak. This corresponds to another major milestone in the lives of many young adults, says coauthor Bin Yu, a research assistant in the epidemiology department.
“At 18, many adolescents leave their parents’ homes to start college or enter the workforce,” Yu says. “They may be more susceptible to influence from peers and they have less monitoring by their parents and the community.”
By age 21, 54 percent of young adults will have used marijuana.
Researchers discovered something else unsuspected when they analyzed the likelihood of marijuana use by race. Adolescents who self-identified as having a multiracial background were significantly more likely to use marijuana than any other racial or ethnic group.
More research is needed to understand the reasons why adolescents from multiracial backgrounds may be at increased risk for initiating marijuana use, Chen says.
“This study finding supports the idea of precision intervention. Intervention programs should be developed for both parents and adolescents, and delivered to the right target population at the right time for the best prevention effect.”
Source: University of Florida