This is Not Cool: The Impact of Menthol and Flavors on E-Cigarette Addiction

While the ongoing opioid epidemic continues to make headlines, nicotine addiction is still the number one cause of preventable death in the United States. Nicotine dependence results in approximately half a million deaths per year, which is nearly 10 times greater than the annual death toll from opioid dependence.

Over the years, nicotine-containing products have evolved to include electronic cigarettes (e-cigarettes). According to “Public Health Consequences of E-Cigarettes,” a congressionally mandated report published in 2018 by the National Academies of Sciences, Engineering, and Medicine (NASEM), there is compelling evidence that American youth find e-cigarettes attractive.

The report also says e-cigarettes may lead adults to stop smoking conventional cigarettes. It is argued that conventional cigarettes have more toxicants and carcinogens than e-cigarettes. Therefore, completely switching to e-cigarettes poses less harm to individuals. I don’t have sufficient space to discuss both the adult and adolescent components, so I will focus on the part regarding adolescent e-cigarette use. In full disclosure, I have twin boys who will one day be adolescents, making me particularly interested in that area of study.

Nicotine is the primary addictive component of all tobacco products. Therefore, it is no surprise that the NASEM report says there is “substantial evidence that e-cigarette use results in symptoms of dependence on e-cigarettes.” Additionally, “…evidence that variability in the characteristics of e-cigarette products (nicotine concentration, flavoring, device type and brand) is an important determinant of the risk and severity of dependence on e-cigarettes.”

This is where my own personal and professional interests come into play. My research is focused on one of those variable characteristics, flavoring. Since 2012, I have studied how flavors may increase the addictive potential of nicotine-containing products. I began this research as a postdoctoral fellow at the California Institute of Technology. At Caltech (yes, the same institute as Sheldon Cooper), I focused on menthol, following reports that smokers of menthol cigarettes quit at lower rates, suggesting that menthol-flavored cigarettes are potentially more addictive.

My research then led me to become an electrophysiologist, which means I use fancy instruments to detect how the function of our neurons (brain cells) change when exposed to addictive substances. I discovered that menthol enhances nicotine’s ability to change neurons critical for addictive behavior. This data was eventually published in the journal Neuropsychopharmacology and was the first preclinical neuroscience report to show that a tobacco flavor—menthol–could enhance nicotine’s addictive potential and also increase nicotine’s addiction-related behavior by directly altering neurons.

When I started my lab at the Marshall University Joan C. Edwards School of Medicine, I focused on flavors that are popular in e-cigarettes and worked to determine how they may impact addictive-related behaviors. In addition to menthol, we found that green apple flavors can alter brain regions that are critical for addiction without nicotine on-board. To reiterate, some flavors, in this case green apple, may contribute to dependence even without nicotine.

When we put this in the perspective of the increase in popularity of some e-cigarettes among adolescents, we have to consider the fact that the previously identified primary addictive component of tobacco products—nicotine—may not be the only key player in the drug dependence associated with e-cigarettes. Flavors may play a significant contribution to the changes in brain cells that trigger dependence (addiction).

Why should we care about this?

E-cigarettes popular among adolescents facilitate dependence, and this is made worse by flavorings. Studies also show that adolescent exposure to nicotine negatively alters behaviors such as self-control and risk for other drug dependencies. To promote the long-term health, safety, and happiness of all our youth, we must not perceive e-cigarettes as a harmless novelty.  They are just as uncool as traditional nicotine products.