Understanding Addiction to Tobacco

Understanding Addiction

There are more than 4,000 chemicals found in the smoke of tobacco products. Of these, nicotine, first identified in the early 1800s, is the primary reinforcing component of tobacco that acts on the brain.

Cigarette smoking is the most popular method of using tobacco; however, there has also been a recent increase in the sale and consumption of smokeless tobacco products, such as snuff and chewing tobacco. These smokeless products also contain nicotine, as well as many toxic chemicals.

The cigarette is a very efficient and highly engineered drug delivery system. By inhaling tobacco smoke, the average smoker takes in 1 to 2 mg of nicotine per cigarette. When tobacco is smoked, nicotine rapidly reaches peak levels in the bloodstream and enters the brain. A typical smoker will take 10 puffs on a cigarette over a period of 5 minutes that the cigarette is lit. Thus, a person who smokes about 1-1/2 packs (30 cigarettes) daily gets 300 "hits" of nicotine to the brain each day. In those who typically do not inhale the smoke, such as cigar and pipe smokers and smokeless tobacco users, nicotine is absorbed through the mucosal membranes and reaches peak blood levels and the brain more slowly.

Immediately after exposure to nicotine, there is a "kick" caused in part by the drug's stimulation of the adrenal glands and resulting discharge of epinephrine (adrenaline). The rush of adrenaline stimulates the body and causes a sudden release of glucose, as well as an increase in blood pressure, respiration, and heart rate. Nicotine also suppresses insulin output from the pancreas, which means that smokers are always slightly hyperglycemic (i.e., they have elevated blood sugar levels). The calming effect of nicotine reported by many users is usually associated with a decline in withdrawal effects rather than direct effects of nicotine.

The Power of Nicotine

Most smokers use tobacco regularly because they are addicted to nicotine. Addiction is characterized by compulsive drug seeking and use, even in the face of negative health consequences. It is well documented that most smokers identify tobacco use as harmful and express a desire to reduce or stop using it, and nearly 35 million of them want to quit each year. Unfortunately, only about 6 percent of people who try to quit are successful for more than a month.

Research has shown how nicotine acts on the brain to produce a number of effects. Of primary importance to its addictive nature are findings that nicotine activates reward pathways—the brain circuitry that regulates feelings of pleasure. A key brain chemical involved in mediating the desire to consume drugs is the neurotransmitter dopamine, and research has shown that nicotine increases levels of dopamine in the reward circuits. This reaction is similar to that seen with other drugs of abuse, and is thought to underlie the pleasurable sensations experienced by many smokers. Nicotine's pharmacokinetic properties also enhance its abuse potential. Cigarette smoking produces a rapid distribution of nicotine to the brain, with drug levels peaking within 10 seconds of inhalation. However, the acute effects of nicotine dissipate in a few minutes, as do the associated feelings of reward, which causes the smoker to continue dosing to maintain the drug's pleasurable effects and prevent withdrawal.

Nicotine withdrawal symptoms include irritability, craving, cognitive and attentional deficits, sleep disturbances, and increased appetite. These symptoms may begin within a few hours after the last cigarette, quickly driving people back to tobacco use. Symptoms peak within the first few days of smoking cessation and may subside within a few weeks. For some people, however, symptoms may persist for months. While withdrawal is related to the pharmacological effects of nicotine, many behavioral factors can also affect the severity of withdrawal symptoms. For some people, the feel, smell, and sight of a cigarette and the ritual of obtaining, handling, lighting, and smoking the cigarette are all associated with the pleasurable effects of smoking and can make withdrawal or craving worse. While nicotine gum and patches may alleviate the pharmacological aspects of withdrawal, cravings often persist. Other forms of nicotine replacement, such as inhalers, attempt to address some of these other issues, while behavioral therapies can help smokers identify environmental triggers of withdrawal and craving so they can employ strategies to prevent or circumvent these symptoms and urges.

Why Quit?

Quitting smoking is one of the most important things you will ever do. Why? Here are just a few good reasons:

• You will live longer and live better.
• Quitting will lower your chance of having a heart attack, stroke, or cancer.
• If you are pregnant, quitting smoking will improve your chances of having a healthy baby.
• The people you live with, especially your children, will be healthier.
• You will have extra money to spend on things other than cigarettes.

Immediate and Long Term Benefits

Within 20 minutes after you smoke that last cigarette, your body begins a series of changes that continue for years.

20 Minutes After Quitting Your heart rate drops.

12 hours After Quitting Carbon monoxide level in your blood drops to normal.

2 Weeks to 3 Months After Quitting Your heart attack risk begins to drop. Your lung function begins to improve.

1 to 9 Months After Quitting Your Coughing and shortness of breath decrease.

1 Year After Quitting Your added risk of coronary heart disease is half that of a smoker's.

5 Years After Quitting Your stroke risk is reduced to that of a nonsmoker's

5-15 years after quitting.

10 Years After Quitting Your lung cancer death rate is about half that of a smoker's. Your risk of cancers of the mouth, throat, esophagus, bladder, kidney, and pancreas decreases.

15 Years After Quitting Your risk of coronary heart disease is back to that of a nonsmoker's.

Need more convincing? Compared to smokers, your:

• Stroke risk is reduced to that of a person who never smoked after 5 to 15 years of not smoking
• Cancers of the mouth, throat, and esophagus risks are halved 5 years after quitting
• Cancer of the larynx risk is reduced after quitting
• Coronary heart disease risk is cut by half 1 year after quitting and is nearly the same as someone who never smoked 15 years after quitting
• Chronic obstructive pulmonary disease risk of death is reduced after you quit Lung cancer risk drops by as much as half 10 years after quitting
• Ulcer risk drops after quitting
• Bladder cancer risk is halved a few years after quitting
• Peripheral artery disease goes down after quitting
• Cervical cancer risk is reduced a few years after quitting
• Low birth weight baby risk drops to normal if you quit before pregnancy or during your first trimester the benefits of quitting

Questions to Think About

Think about the following questions before you try to stop smoking. You may want to talk about your answers with your health care provider.

1. Why do you want to quit?

2. When you tried to quit in the past, what helped and what didn't?

3. What will be the most difficult situations for you after you quit? How will you plan to handle them?

4. Who can help you through the tough times? Your family? Friends? Health care provider?

5. What pleasures do you get from smoking? What ways can you still get pleasure if you quit?

Here are some questions to ask your health care provider.

1. How can you help me to be successful at quitting?

2. What medication do you think would be best for me and how should I take it?

3. What should I do if I need more help?

4. What is smoking withdrawal like? How can I get information on withdrawal?

TERMS:

• addiction: A chronic, relapsing disease characterized by compulsive drug seeking and abuse and by long-lasting neurochemical and molecular changes in the brain.
• adrenal glands: Glands located above each kidney that secrete hormones, e.g., adrenaline.
• craving: A powerful, often uncontrollable desire for drugs.
• dopamine: A neurotransmitter present in regions of the brain that regulate movement, emotion, motivation, and feelings of pleasure.
• emphysema: A lung disease in which tissue deterioration results in increased air retention and reduced exchange of gases. The result is difficulty breathing and shortness of breath.
• hyperglycemic: The presence of an abnormally high concentration of glucose in the blood.
• neurotransmitter: A chemical that acts as a messenger to carry signals or information from one nerve cell to another.
• nicotine: An alkaloid derived from the tobacco plant that is responsible for smoking's psychoactive and addictive effects.
• pharmacokinetics: The pattern of absorption, distribution, and excretion of a drug over time.
• rush: A surge of euphoria that rapidly follows administration of some drugs.
• tobacco: A plant widely cultivated for its leaves, which are used primarily for smoking; the N. tabacum species is the major source of tobacco products.
• withdrawal: A variety of symptoms that occur after chronic use of an addictive drug is reduced or stopped.

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