E-cigarettes and vapes: Do they work for smoking cessation and should we be recommending their use?

The liquid in the E-cig cartridge typically contains not only nicotine but a number of chemical compounds with potentially deleterious or unknown health risks. The 3 main ingredients include:

• a solvent of glycerin and/or propylene glycol
• nicotine in various concentrations
• flavorings.

The glycerin or propylene glycol forms the basis for the aerosol. Nicotine concentrations vary from 0 (denicotinized) to 35 mcg per puff.⁴ A study reported 7,700 unique flavors available for vaping liquid.⁵ The liquid also contains impurities, such as anabasine, which has effects on the α-7 nicotinic acetylcholine receptor and its principal use is as an insecticide and β-nicotyrine, which inhibits cytochrome P450 2A.

Epidemiology and end-user perspectives

In 2014, 12.4% of U.S. adults classified themselves as “ever users” of ENDS (used at least once) and 3.7% of adults classified themselves as current users, according to the National Health Interview Study.⁶ Importantly, among E-cig users who had not used combustible cigarettes, young adults (age 18 to 24) were more likely to have tried ENDS than older adults. ENDS are becoming more popular across the globe. A study in the European Union found that ever users of ENDS most commonly were current cigarette smokers (31%) followed by former (10.8%) and never smokers (2.3%).⁷

ENDS use is relevant for mental health professionals because of the high rate of comorbid tobacco use disorder in individuals with psychiatric conditions. For example, 2 U.S. population surveys^8,9 revealed those with mental health conditions were 1.5 to 2 times more likely to have tried ENDS and 2 to 3 times more likely to be current users. Those with psychiatric illness reported similar reasons for ENDS use as other individuals, including “just because,” use as a smoking cessation aid, ease of use, and perceived safety vs combustible cigarettes.

A recent review that included 9 studies focusing on ENDS use in those with mental illness reported mixed findings on the utility of these devices to reduce or stop use of combustible cigarettes.¹⁰ Additionally, it is important to monitor the use of cigarettes and ENDS in patients with psychiatric illness because the byproducts of tobacco smoke can affect the metabolism of some psychotropic medications.¹¹ Although reduced use of combustible cigarettes could lead to lower dosing of some psychotropics, an unreported decrease in combustible cigarette use could lead to supratherapeutic drug levels. There are no data on the effect of ENDS on the metabolism of psychotropics.

ENDS are increasingly popular among adolescents. In 2015, there were an estimated 4.6 million current tobacco users among middle/high school youths in the United States and 3 million current ENDS users, according to the National Youth Tobacco Surveys.¹² The shift from combustible cigarettes to ENDS is notable, with an increase in the percentage of current E-cig users and a decrease in the percentage of exclusive combustible cigarette users. In addition, there has been no change in the prevalence of lifetime tobacco users.¹² This is a global issue, as reports of ever use of ENDS by adolescents range from 6.5% to 31% in the United States, 14.6% in Canada, and 4.7% to 38.5% in Europe.¹³ Based on these trends, the U.S. Surgeon General released a statement warning against the use of ENDS in youth because of the lack of safety data and strong association with use of tobacco products.¹⁴

There are a number of possible reasons for the increasing popularity of ENDS, including the product’s novelty, lack of regulations regarding their sale, availability of flavorings, and the perception that ENDS are safe alternatives to cigarettes. E-cig–using youths have described ENDS as “not at all harmful” and “not at all addictive” and believe that ENDS with flavoring are less harmful than those without.¹⁵ Although studies in adults show some users reporting that ENDS are less satisfying, they are seen as useful in decreasing craving and a safer alternative to cigarettes.^16,17