A national study found that alcohol, cannabis, and nicotine use increased steadily from ages 9 to 17, with more than one-third of teens reporting lifetime use of at least one substance by age 16.
Girls began reporting higher rates of alcohol, cannabis, nicotine, and multiple-substance use than boys starting around age 13.
Researchers say the findings provide an updated picture of when substance use typically emerges during adolescence, helping inform future prevention efforts.
Substance use during the teenage years remains a major public health concern, but new research suggests it tends to develop gradually rather than appearing suddenly in high school.
Researchers from the University of California San Diego analyzed one of the nation's largest long-term studies of young people to better understand when adolescents begin experimenting with substances and how those patterns change as they get older.
The study found that alcohol, cannabis, and nicotine were the substances most commonly reported by participants, with use increasing steadily throughout adolescence. By age 16, about 38% of teens had reported using at least one of those substances at some point in their lives. Researchers also found that nearly 15% of participants reported using more than one substance, with nicotine and cannabis being the most common combination.
How researchers tracked substance use over time
The findings were based on data from 11,880 children and adolescents participating in the national Adolescent Brain Cognitive Development (ABCD) Study, one of the largest long-term studies of youth in the United States.
Participants were followed from ages 9 to 17 through annual and mid-year assessments conducted between 2016 and early 2024.
Rather than looking at a single snapshot in time, researchers examined how substance use changed as the same participants grew older. They also compared patterns between boys and girls and looked at both single-substance use and polysubstance use, which refers to using two or more substances.
To help ensure the findings reflected U.S. adolescents more broadly, the researchers adjusted their estimates to match national demographic characteristics.
What the findings could mean for families
One of the clearest patterns involved differences between boys and girls. Before age 12, boys reported slightly higher rates of substance use. Beginning around age 13, however, girls reported higher rates of alcohol, cannabis, and nicotine use, with the largest gap seen for nicotine.
At age 14, for example, 11.3% of girls reported nicotine use compared with 8% of boys, while cannabis use was reported by 8.8% of girls versus 7% of boys and alcohol use by 8.3% of girls compared with 6.5% of boys. These differences also extended to polysubstance use, particularly combinations involving nicotine.
The researchers say these updated estimates provide an important benchmark for understanding when substance use typically emerges during adolescence.
They note that tracking these patterns can help scientists better study how early substance use may relate to brain development, mental health, and long-term health outcomes, while also informing future prevention and intervention efforts.