The six risk behaviors are categories of health-related actions tracked by the CDC’s Youth Risk Behavior Surveillance System (YRBSS), a nationwide survey of high school students conducted every two years since 1991. These six categories account for the major causes of death, disability, and chronic disease among young people in the United States: behaviors that contribute to unintentional injuries and violence, tobacco use, alcohol and other drug use, sexual behaviors that lead to unintended pregnancy or sexually transmitted infections, unhealthy dietary behaviors, and physical inactivity.
These aren’t random groupings. More than 60% of deaths among children and adolescents in the U.S. result from injury-related causes, and many of those injuries trace directly back to preventable behaviors. The remaining categories drive the chronic diseases that develop later in life. Up to 80% of cardiovascular disease and type 2 diabetes cases are attributable to just three modifiable factors: unhealthy diet, physical inactivity, and tobacco use. What makes adolescence so critical is that these behaviors tend to cluster together in young people, and their combined effect on long-term health is greater than the sum of each one alone.
Behaviors That Contribute to Injuries and Violence
Unintentional injury is the single leading cause of death for adolescents in the United States. The specific behaviors tracked in this category include not wearing seatbelts, riding with a driver who has been drinking, driving after drinking, and carrying weapons. Violence-related behaviors include physical fighting, dating violence, bullying, and experiences of sexual violence.
These behaviors often overlap with substance use. Binge drinking roughly doubles the odds of experiencing an intentional injury, and carrying a weapon more than doubles them. One analysis of emergency department studies estimated that drinking was a contributing factor in 43% of violence-related injuries. The most recent YRBSS data from 2023 showed concerning increases in students’ experiences of violence at school compared to previous years, even as some other risk categories improved.
Tobacco Use
This category covers cigarettes, cigars, smokeless tobacco, and e-cigarettes. The landscape has shifted dramatically since the YRBSS began. Traditional cigarette smoking among high school students hit its lowest level ever recorded in 2024, with only 1.4% of students reporting current use. E-cigarettes, however, became the dominant tobacco product among youth over the past decade.
In 2024, about 7.8% of high school students (1.21 million) and 3.5% of middle school students (410,000) reported currently using e-cigarettes. That’s a decline from 2023, when 2.13 million youth were current e-cigarette users. Overall, 10.1% of high school students reported using some form of tobacco product. While the downward trend is real, nicotine exposure during adolescence affects brain development and increases the likelihood of long-term addiction.
Alcohol and Other Drug Use
This category tracks binge drinking, marijuana use, and the use of other illicit drugs, including prescription drug misuse. Substance use in adolescence is linked not only to immediate dangers like overdose and impaired driving but also to disrupted brain development, academic problems, and higher rates of addiction in adulthood.
The 10-year trends from the YRBSS are encouraging here. From 2013 to 2023, there were consistent decreases in students’ use of substances across the board. Still, substance use remains a significant risk factor for other categories on this list. Youth who report binge drinking are far more likely to experience both intentional and unintentional injuries, and alcohol use is a major driver of risky sexual behavior.
Sexual Behaviors
The YRBSS monitors sexual activity, condom use, the number of sexual partners, and whether students were tested for STIs or HIV. The goal isn’t to track sexual activity itself but to identify behaviors that lead to unintended pregnancy and sexually transmitted infections.
The numbers tell a mixed story. Adolescent sexual activity has declined since 2013, and teen pregnancy rates have dropped sharply. The teen birth rate in 2022 was 13.6 per 1,000 females ages 15 to 19, down 78% from the 1991 peak of 61.8. But protective behaviors are also declining. Condom use has dropped, and fewer adolescents are getting tested for STIs or HIV. That matters because young people ages 15 to 24 account for nearly half of all reported chlamydia, gonorrhea, and syphilis cases despite making up only about 25% of the sexually active population. People ages 13 to 24 accounted for 20% of new HIV diagnoses in 2022. Only 61% of adolescents ages 13 to 17 were up to date on the HPV vaccine in 2023.
Unhealthy Dietary Behaviors
This category tracks patterns like how often students eat fruits and vegetables, how many sugar-sweetened beverages they consume, and whether they skip breakfast. The concern is that dietary habits formed during adolescence tend to persist into adulthood, raising the risk of obesity, heart disease, and type 2 diabetes.
The specific patterns flagged as high-risk include eating too many highly processed foods, consuming too much added sugar (particularly from sweetened drinks), and getting too little fiber, fruits, and vegetables. These patterns don’t exist in isolation. Poor diet combined with physical inactivity is one of the most powerful predictors of chronic disease later in life, and both behaviors tend to take root during the teenage years.
Physical Inactivity
The recommended guideline for young people is at least 60 minutes of physical activity per day. Fewer than 20% of youth in the U.S. meet that standard, based on the 2022-2023 National Survey of Children’s Health. Only about 46% of youth participated in organized sports in the past year.
The gaps vary by income, sex, and geography. Youth from lower-income households and those in rural areas are less likely to meet activity guidelines. Physical inactivity during adolescence increases the risk of obesity and contributes to the same cluster of chronic diseases driven by poor diet: cardiovascular disease, type 2 diabetes, and certain cancers. Because these behaviors reinforce each other, a sedentary teenager who also eats poorly faces compounding risk that accelerates over decades.
Why These Six Categories Matter Together
The power of this framework is that it captures the behaviors most responsible for both immediate harm and long-term disease. Injuries and violence kill young people now. Tobacco, poor diet, inactivity, and substance use build toward the chronic diseases that kill adults later. Sexual risk behaviors fall somewhere in between, with consequences that can emerge within weeks or shape someone’s reproductive health for years.
Research consistently shows these behaviors cluster. A teenager who binge drinks is more likely to carry a weapon, have unprotected sex, and eat poorly. That clustering effect means the combined health risk is greater than you’d expect from adding up each behavior on its own. It also means that interventions targeting one behavior often produce improvements across several categories, which is exactly why the CDC chose to monitor all six together in a single surveillance system.