How do tobacco and nicotine affect the brain?
Like other drugs, nicotine increases levels of a neurotransmitter called dopamine. Dopamine is released normally when you experience something pleasurable like good food, your favorite activity, or spending time with people you care about. When a person uses tobacco products, the release of dopamine causes similar effects. This effect wears off quickly, causing people who smoke to get the urge to light up again for more of that good feeling, which can lead to addiction.
A typical smoker will take 10 puffs on a cigarette over the period of about 5 minutes that the cigarette is lit. Thus, a person who smokes about 1 pack (25 cigarettes) daily gets 250 “hits” of nicotine each day.
Studies suggest that other chemicals in tobacco smoke, such as acetaldehyde, may enhance the effects of nicotine on the brain.
When smokeless tobacco is used, nicotine is absorbed through the mouth tissues directly into the blood, from where it goes to the brain. Even after the tobacco is removed from the mouth, nicotine continues to be absorbed into the bloodstream. Also, the nicotine stays in the blood longer for users of smokeless tobacco than for smokers.
What are the other effects of tobacco and nicotine?
When nicotine enters the body, it initially causes the adrenal glands to release a hormone called epinephrine (adrenaline). The rush of adrenaline stimulates the body and causes an increase in blood pressure, heart rate, and breathing.
Most of the harm to the body is not from the nicotine, but from other chemicals contained in tobacco or produced when burning it—including carbon monoxide, tar, formaldehyde, cyanide, and ammonia. Tobacco use harms every organ in the body and can cause many problems. The health effects of smokeless tobacco are somewhat different from those of smoked tobacco. These risks include: nicotine addiction and poisoning, diseases of the mouth and teeth, cancer of the mouth, esophagus or pancreas, and increased risk of heart disease and stroke.
For people who do not smoke, secondhand smoke—exposure to exhaled smoke and smoke given off by the burning end of tobacco products—increases the risk for many diseases. Each year, an estimated 58 million Americans are regularly exposed to secondhand smoke and more than 42,000 nonsmokers die from diseases caused by secondhand smoke exposure.
Centers for Disease Control and Prevention. Smoking and Tobacco Use: Fast Facts. Atlanta, GA. December 2015. Available here.
What about E-Cigarettes?
E-cigarettes are fairly new products. They’ve only been around for about a decade. Therefore, researchers are just in the early stage of studying the health effects for people who use these products or who are exposed to the aerosol (vapor) secondhand.
E-cigarettes are designed to deliver nicotine without the other chemicals produced by burning tobacco leaves. Puffing on the mouthpiece of the cartridge activates a battery-powered inhalation device (called a vaporizer). The vaporizer heats the liquid inside the cartridge which contains nicotine, flavors, and other chemicals. The heated liquid turns into an aerosol (vapor) which the user inhales—referred to as “vaping.”
Because they do not burn tobacco, e-cigarettes are not expected to be as harmful to the lungs as other tobacco products. But since they are so new, we do not know for sure. Health experts have raised many questions about the safety of these products, particularly for teens:
- Testing of some e-cigarette products found the aerosol (vapor) to contain known cancer-causing and toxic chemicals, and particles from the vaporizing mechanism that may be harmful. The health effects of repeated exposure to these chemicals are not yet clear.
- There is animal research which shows that nicotine exposure may cause changes in the brain that make other drugs more rewarding. If this is true in humans, as some experts believe, it would mean that using nicotine in any form would increase the risk of other drug use and for addiction.
- Some research suggests that e-cigarette use may serve as a “gateway” or introductory product for youth to try other tobacco products, including regular cigarettes, which are known to cause disease and lead to early death. A recent study showed that students who have used e-cigarettes by the time they start 9th grade are more likely than others to start smoking traditional cigarettes and other smoked tobacco products within the next year.
- The liquid in e-cigarettes can cause nicotine poisoning if someone drinks, sniffs, or touches it. Recently there has been a surge of poisoning cases in children under age 5. There is also concern for users changing cartridges and for pets.
Rigotti NA. e-Cigarette use and subsequent tobacco use by adolescents: new evidence about a potential risk of e-cigarettes. JAMA. 2015;314(7):673-674.
Can you get addicted to tobacco and nicotine products?
Yes. Whether a person smokes tobacco products or uses smokeless tobacco, the amount of nicotine absorbed in the body is enough to make someone addicted. When this happens, the person continues to seek out the tobacco even though he or she understands the harm it causes. Nicotine addiction can cause:
Tolerance: Over the course of a day, someone who uses tobacco products develops tolerance—more nicotine is required to produce the same initial effects. Some of this tolerance is lost overnight. In fact, people who smoke often report that the first cigarette of the day is the strongest or the “best.”
Withdrawal: When people quit using tobacco products, they usually experience withdrawal symptoms, which often drive them back to tobacco use. Nicotine withdrawal symptoms include:
- problems with thinking and paying attention
- sleep problems
- increased appetite
- craving, which may last 6 months or longer, and can be a major stumbling block to quitting