Teens who try marijuana or other drugs are at greater risk of developing a drug addiction than those who wait a few years before experimenting with drugs, a new study finds.
"Though not everyone who uses a drug will develop addiction, adolescents may develop addiction to substances faster than young adults," said study co-lead author Dr. Nora Volkow. She is director of the U.S. National Institute on Drug Abuse (NIDA).
"We know that young people are more vulnerable to developing substance use disorders, but knowledge is limited on how the prevalence of specific substance use disorders varies by time since first substance use or misuse among adolescents and young adults in the United States," she noted.
"This study provides further evidence that delaying substance exposure until the brain is more fully developed may lower risk for developing a substance use disorder," Volkow said in an NIDA news release.
For the study, Volkow's team analyzed data from the U.S. National Surveys on Drug Use and Health to assess the proportion of adolescents (aged 12 to 17) and young adults (aged 18 to 25) who had an addiction at various intervals since the first time they used or misused one of nine different drugs: tobacco; alcohol; cannabis; cocaine; methamphetamine; heroin; and prescription drugs (opioids, stimulants and tranquilizers).
Addiction was evaluated at four points since first drug use: 12 months or less; more than 12 through 24 months; more than 24 through 36 months; and more than 36 months. The study period covered from 2015 to 2018.
Rates of past-year cannabis use disorder were greater among teens than young adults at all the time points since first use of the drug. For example, within 12 months since first cannabis use, nearly 11% of adolescents had the disorder, compared with just over 6% of young adults.
Rates of non-medical use of prescription drugs were also greater among teens than young adults at all time points since first use. For example, within 12 months since first misuse of prescription drugs:
- 11% of adolescents had prescription opioid use disorder versus 7% of young adults.
- 14% of adolescents had prescription stimulant use disorder versus 4% of young adults.
- 11% of adolescents had prescription tranquilizer use disorder versus nearly 5% of young adults.
Teens and young adults had similar rates of tobacco and alcohol addiction within 12 months of first using the substances, but the rate was higher among young adults in subsequent time periods examined by the researchers.
Estimates of cocaine, methamphetamine and heroin use among teens were too small to report, but about 31% of young adults developed heroin addiction and nearly one-quarter of young adults developed methamphetamine addiction within a year after first trying the drugs, the findings showed.
The study, published March 29 in JAMA Pediatrics, highlights young people's vulnerability to addiction, the researchers said.
According to study co-author Emily Einstein, "Research has shown that brain development continues into a person's 20s, and that age of drug initiation is a very important risk factor for developing addiction." Einstein is chief of NIDA's Science Policy Branch.
"This underscores the importance of drug use prevention and screening for substance use or misuse among adolescents and young adults," she explained. "Offering timely treatment and support to young people who need it must be a public health priority."