One-sixth of adolescent smokers report harder drug use, followed by higher rates of depression

In a UC San Francisco study of 176 adolescent smokers in San Francisco, 96 percent reported using at least two substances other than cigarettes.

While most used alcohol, marijuana and other tobacco products, 16 percent – or more than one in six teen smokers – reported taking harder drugs, including cocaine, hallucinogens, Ecstasy, and misused prescription medications.

"Most of these adolescents smoked five or fewer cigarettes a day," said lead author Karma McKelvey, MPH, PhD, a postdoctoral fellow with the UCSF Center for Tobacco Control Research and Education. "This tells us that multi-drug use among adolescents may be more prevalent than we think, and that even kids who smoke only occasionally are likely to be doing other drugs."

Teens who reported using harder drugs at the beginning of the study were more likely than other participants to report depressive symptoms one, two and three years later. The proportion of teens reporting harder drug use also remained consistent over the course of the study, McKelvey said, "which implies that patterns of smoking and drug use established in adolescence can be chronic and persist over time."

The study will be published Dec. 12, 2016 in Addictive Behaviors.

McKelvey recommended that depression scores could be used to more accurately identify teenagers who are candidates for drug prevention and cessation programs.

"When you ask a teenager if he or she is a smoker, the most likely answer will be no," she said. "Adolescents do not necessarily identify as smokers, even if they do occasionally smoke cigarettes. However, kids who do not self-identify as smokers are more likely to be overlooked for inclusion in prevention and cessation programs, the idea being that if they don't smoke, they're less likely to drink or do drugs. Instead, let's perhaps look at their depression scores. Let's ask adolescents how they're feeling and doing. Go deeper and find out what's really going on with them."

While the study results contradicted the conventional notion that light smoking progresses to heavy smoking, and none of the teens seemed interested in smoking more as time went on, McKelvey recommended that smoking prevention and cessation programs begin in elementary and middle school.

"We tend not to worry as much about light smokers as we do heavy smokers," she said. "This study shows us that it's important to intervene as early as possible."