Nicotine is the reason that people become addicted to smoking cigarettes, and get lung, head and neck cancers as a result, but the nicotine in electronic cigarettes is also considered addictive, according to the National Institute on Drug Abuse (NIDA). Addiction, characterized by compulsive drug seeking in the face of negative health consequences, is felt by smokers who try to quit — of the almost 35 million who try to quit smoking every year, more than 85 percent relapse, usually within a week, according to NIDA.
Research has shown that nicotine increases dopamine levels in the reward circuits of the brain, according to NIDA. Cigarette smoking rapidly distributes nicotine to the brain, with levels peaking within 10 seconds and dissipating quickly, resulting in the need to keep smoking. But less is known about the delivery of nicotine via electronic cigarettes, in which the nicotine vapors are inhaled without any of the tobacco smoke.
For more information about electronic cigarettes, NIDA recommended that we talk to Thomas Eissenberg, Ph.D., professor of psychology and co-director of the Center for the Study of Tobacco Products at Virginia Commonwealth University in Richmond.
Concerns about youth
Nicotine affects the brain by “binding to acetylcholine receptors,” said Eissenberg. A mild psychomotor stimulant, nicotine “continually bathes receptors, resulting in cellular changes that lead to dependence, meaning that the drug is now necessary for normal function to occur,” he said. “There are major concerns about youth becoming nicotine-dependent via electronic cigarettes,” he said. “First of all, do we want nicotine-dependent kids?” There also may be risks involved with the daily electronic cigarette use that would accompany dependence, he said.
So far, while it is possible that someone could transition from electronic cigarettes to tobacco cigarettes, there is not much information about whether this is happening or not, said Eissenberg. It is also possible that young people could use electronic cigarettes as a way to use other drugs — for example, dripping hashish oil on the heater.
Question about delivery
Nicotine causes physical dependence, and electronic cigarettes have the potential to cause physical dependence if they contain nicotine, he said. “Of course, if they do not deliver any of the nicotine they contain to their users, then that potential cannot be realized.” Eissenberg and Andrea Rae Vansickel, Ph.D., in a paper published in Nicotine & Tobacco Research in January, showed that if electronic cigarettes do deliver nicotine, then they can cause physical dependence.
“Based on data I have seen, I think there is little doubt that at least some e-cigarettes marketed in the U.S. today can support nicotine dependence in some users,” Eissenberg told ADAW. “We have demonstrated beyond any doubt that some experienced e-cigarette users receive cigarette-like nicotine doses when they use these products.”
Not approved as quitting tool
The Food and Drug Administration (FDA) has not approved any claims by electronic cigarettes that they can be used as a therapeutic smoking-cessation product, like nicotine gum or patches. This kind of therapeutic use “may apply to e-cigarettes, or it may not,” said Eissenberg.
That’s because there is more in the electronic cigarettes than nicotine, and what goes into the lungs, he said. “The difference between FDA-approved nicotine-containing tobacco-cessation pharmacotherapies and e-cigarettes is that e-cigarettes involve delivering more than nicotine by itself, and that what is delivered that is not nicotine is likely delivered to the human lung with unknown health consequences,” said Eissenberg. The “vehicle” for the nicotine delivery with electronic cigarettes is propylene glycol or vegetable glycerine, in which the nicotine is dissolved, as well as a variety of other chemicals used for flavor, said Eissenberg. There may also be “other chemicals of unknown purpose,” he said, noting that manufacturers are not required to report the contents of the liquid that goes in the electronic cigarette cartridge to be vaporized when heated.
Eissenberg is very concerned about saying electronic cigarettes are safe when so little is known about them. “What is the influence of inhaling these substances into the human lung, hour after hour, day after day? Do they cause cancer in humans when inhaled daily for several years? Do they cause lung disease in humans when inhaled daily for several years? Do they cause any other diseases in humans when inhaled daily for several years? I am not sure anyone has the answers to these questions.”
Eissenberg added there is no data that show that electronic cigarettes reduce cancer.
Finally, there are some electronic cigarette companies that, trying to evade future regulation by the FDA as a tobacco product, claim that their nicotine comes from other plants. Electronic cigarettes are legally defined as tobacco products if the nicotine comes from tobacco, said Eissenberg. But no matter where the nicotine came from, it is still addictive, he said. “Nicotine is nicotine, regardless of the source,” he said.