Teenagers with moderate mental health problems who may not have considered smoking conventional cigarettes are turning to electronic cigarettes, a new USC study has found.

Mental health and behavioral problems such as alcohol and drug abuse are well-documented risk factors that push teens to smoke, said Adam Leventhal, PhD, lead author and associate professor of preventive medicine and psychology at the Keck School of Medicine of USC.

The situation, however, is different for teens who vape e-cigarettes, battery-operated devices that deliver flavors and often nicotine in the form of vaporized aerosols. Surveyed teens who picked up vaping had emotional and behavioral problems that fell midway between smokers and teens who neither vaped nor smoked.

“In the past three years, there have been dramatic increases in recreational use of e-cigarettes among teens,” Leventhal said. “Our study raises questions of whether e-cigarettes may be recruiting lower-risk teens with fewer mental health problems who might not have been interested in any nicotine or tobacco products if e-cigarettes did not exist. Electronic cigarettes could be bringing a population of lower-risk teens into nicotine use.”

Published online Nov. 20 in the Journal of Psychiatric Research, the study surveyed 3,310 ninth-grade students in 10 Los Angeles-area high schools. The students answered questions about conventional or e-cigarette use, anxiety disorders, depression, bipolar disorder, substance use and abuse, and traits such as impulsivity, which are linked with poor mental health.

Teenagers who used prescription drugs to get high and those with more symptoms of depression, social phobia, generalized anxiety disorder, panic disorder, obsessive-compulsive disorder and other emotional issues were more likely to smoke than to vape e-cigarettes, according to researchers.

The litany of emotional issues did not greatly affect nonsmokers. On the other hand, adolescents who both vaped and smoked had the poorest mental health, the study found.

This is the first time researchers identified mental and behavioral conditions associated with e-cigarette-only use as well as dual use — that is, both vaping and smoking.

Successful public campaigns have made smoking less socially acceptable and have successfully deterred the majority of young people from smoking, particularly lower-risk teens without mental health and behavioral problems. The same cannot be said about vaping.

“Some people have said that it doesn’t matter if teens experiment with e-cigarettes because they would have experimented with regular cigarettes anyway,” said Jennifer Unger, PhD, study co-author and professor of preventive medicine at Keck Medicine of USC. “This study shows that e-cigarettes are attracting a lower-risk group of teens: Those who would not ordinarily be inclined to smoke cigarettes because of the social norms against smoking. E-cigarettes are increasing the risk of disease among this low-risk group.”

In recent years, smoking has declined in middle and high school students, but the use of electronic cigarettes in this group tripled from 2013 to 2014, according to the Centers for Disease Control and Prevention.

Today’s teens perceive e-cigarettes as less harmful, addictive, smelly and difficult to obtain than conventional cigarettes, Leventhal said. Flavors such as Skittles and Sweet Tarts would obviously entice young people, he added.

“E-cigarette use could be associated with moving on to harmful, combustible forms of tobacco, such as cigarettes, cigars and hookah,” Leventhal said, citing his earlier study, which found that vaping could be a gateway to smoking. “When young people start smoking early in adolescence, they are at greater risk of becoming regular tobacco users in adulthood and to becoming a victim of tobacco-related illness.”

The National Institutes of Health supported this study. Researchers from the University of California, San Diego School of Medicine and University of Pennsylvania, Perelman School of Medicine also contributed to this research.

— Zen Vuong