There are calls to ban vaping because it has pleasant flavors and an addictive component and that combination may lead to disease but while there are zero deaths attributable to nicotine so far, there is an actual socially acceptable carcinogen that also uses flavors to increase use - alcohol.

Yet the future looks bleak if recent survey results hold true. They find that compared to just a generation ago, college students - and alcohol, like smoking, is most often a pediatric condition - are drinking less alcohol.

But that may not translate to increased public health because marijuana is still smoking, and smoking kills. And that has gone up due to legalization and therefore greater social acceptance.

Between 2002 and 2018, the number of adults aged 18-22 in the U.S. who abstained from alcohol increased from 20% to 28% for those in college and from about 24% to 30% for those not in school. Alcohol abuse among both groups decreased by roughly half but the number of young adults using marijuana, as well as co-using alcohol and marijuana, has increased. 

The survey analysis examined how alcohol and marijuana abstinence, co-use and use disorders have changed in 18-to-22-year-olds as a function of college status, using data from a nationally representative survey of 182,722 young adults. It also looked at prescription drug use and misuse as a function of alcohol and marijuana use, from 2015 to 2018. 

"We're encouraged by the significant decreases in alcohol use disorder--for both college and noncollege students," said lead author Sean Esteban McCabe, director of the Center for the Study of Drugs, Alcohol, Smoking and Health at the University of Michigan School of Nursing. "The prevalence of alcohol use disorder in both groups in 2018 was roughly half of what it was in 2002. We are excited to learn about these drops in disordered drinking, as alcohol-related consequences are one of the leading causes of mortality and morbidity for young adults."

The findings indicate that the substance use landscape has changed over the past 20 years, with more young adults using or misusing several different substances, as opposed to just marijuana or alcohol.

For example, from 2015 to 2018, only 2.5% of young adults who abstained from both alcohol and marijuana reported misusing prescription drugs, while 25.1% of co-users misused prescription drugs. That is a tenfold difference with potentially dangerous consequences.

Abusing multiple substances is often more dangerous than abusing a single substance.

"Interventions that focus solely on one substance will be less effective than interventions that take a more holistic polysubstance use perspective," McCabe said. "The findings of our study reinforce the complex task health professionals have of detecting and developing effective interventions to reduce consequences associated with polysubstance use, such as co-use of alcohol and marijuana."