Cannabis, prescription drug misuse at younger age quickens substance use disorder onset
Younger age at first cannabis use or prescription drug misuse was linked to faster development of substance use disorders, according to study results in a research letter published in JAMA Pediatrics.
“We have known for a long time that the younger people are when they first start using drugs, the more likely they are to develop a substance use disorder,” Nora Volkow, MD, director of NIH’s National Institute on Drug Abuse, told Healio Psychiatry. “In this study, we wanted to expand on this research by investigating how the prevalence of specific substance use disorders varies by time since first substance use or misuse among adolescents aged 12 to 17 years and young adults aged 18 to 25 years in the United States. Moreover, after controlling for potential confounding factors, we wanted to examine whether the prevalence of specific past-year substance use disorders differed by substance, age group and time since initiation.”
Volkow and colleagues obtained data from participants of the 2015 to 2018 National Surveys on Drug Use and Health (NSDUH) of the Substance Abuse and Mental Health Services Administration. They did not include prescription drug data between 2005 and 2014 since not all initiation dates were collected between 2015 and 2018. The NSDUH included nationally representative data on substance use according to lifetime use, past-year use and initiation date, as well as substance use disorders, among noninstitutionalized civilian populations.
Results showed alcohol, cannabis and tobacco were the most frequently used substances. Adolescents’ prevalence of lifetime substance use in 2018 was 26.3% (95% CI, 25.4-27.2) for alcohol, 15.4% (95% CI, 14.7-16.1) for cannabis and 13.4% (95% CI, 12.7-14.1) for tobacco. Young adults’ prevalence of lifetime substance use in 2018 was 79.7% (95% CI, 78.9-80.5) for alcohol, 51.5% (95% CI, 50.4-52.6) for cannabis and 55% (95% CI, 53.9-56.1) for tobacco.
Substance use disorder prevalence varied according to substance, age group and time since initiation. Adolescents had an adjusted prevalence of cannabis use disorder of 10.7% (95% CI, 9.3-12.3), whereas young adults had an adjusted prevalence of 6.4% (95% CI, 5.2-7.9), within 1 year of initiation. At more than 36 months, this prevalence was 20.1% (95% CI, 18-22.3) among adolescents and 10.9% (95% CI, 10.3-11.4) among young adults.
The two groups had the same prevalence of alcohol use disorder and nicotine dependence within 12 months of initiation; however, young adults had a higher prevalence at subsequent timepoints.
Young adults in 2018 had a prevalence of lifetime use of 11.4% (95% CI, 10.7-12.1) for cocaine, 2.5% (95% CI, 2.2-2.8) for methamphetamine and 1.3% (95% CI, 1.1-1.5) for heroin. The researchers did not report estimates for these drugs for adolescents because of limited samples. In 2014, adolescents had a prevalence of lifetime misuse of prescription drugs of 9.2% (95% CI, 8.7-9.7) compared with 26.3% (95% CI, 25.4-27.2) among young adults.
Adolescents had consistently higher adjusted prevalence of prescription opioid use disorder, prescription stimulant use disorder and prescription tranquilizer use disorder than young adults among those with lifetime misuse.
“The consistently higher prevalence of cannabis use disorder and prescription drug use disorders among adolescents than among young adults underscores adolescents’ vulnerability to substance use disorders and suggests reconsidering screening for substance use among adolescents in primary care settings,” Volkow said. “These findings provide further evidence that primary care providers should be screening their adolescent and young adult patients for substance use and use disorders. In addition, these results underscore the importance of drug use prevention efforts that seek to delay substance exposure until the brain is more fully developed and is less vulnerable to developing a substance use disorder.”