Nicotina

NICOTINE
Definition: Nicotine dependence is the physical vulnerability of your body to the chemical nicotine, which is potently addicting when delivered by various tobacco products. Smoke from cigarettes, cigars and pipes contains thousands of chemicals, including nicotine. Nicotine is also found in chewing tobacco.
Nicotine produces physical and mood-altering effects in your brain that aretemporarily pleasing; these effects reinforce your continued use of tobacco and nicotine dependence.
Being addicted to tobacco brings you a host of health problems related to the substances in tobacco smoke. These effects include damage to your lungs, heart and blood vessels. Smokers have significantly higher rates of heart disease, stroke and cancer.
Millions of Americans smoke, andsmoking is the leading preventable cause of death in the United States. Men who don't quit smoking lose an average of 13.2 years of life, while smoking women lose even more — an average of 14.5 years.
Overcoming nicotine dependence is difficult and takes commitment, support and time. The sooner you quit smoking, the better. But even if you're a longtime smoker, stopping your nicotine dependence plustaking healthy lifestyle steps can reverse much of the damage smoking has done to your body.
Symptoms
Nicotine dependence may mean you have these signs and symptoms:
You can't stop smoking. You've made one or more serious, but unsuccessful, attempts to stop.
You experience strong withdrawal symptoms when you try to stop. Your attempts at stopping have caused physical signsand symptoms of addiction, such as craving for tobacco, anxiety, irritability, restlessness, difficulty concentrating, headache, drowsiness, stomach upset, even constipation or diarrhea.
You keep smoking despite health problems. Even though you've developed problems with your lungs or your heart, you haven't stopped or can't stop.
You give up social or recreationalactivities in order to smoke. You may stop going to certain restaurants or stop socializing with certain family members or friends because you can't smoke in these situations.
Your degree of addiction depends in part on how much you smoke and how long you've smoked.
Causes
Tobacco smoke delivers at least 60 known cancer-causing chemicals, tiny amounts of poisons including arsenic andcyanide, and more than 4,000 other substances to your body.
Nicotine is the chemical in tobacco that keeps you smoking. It can be as addictive as cocaine. It increases the release of a brain chemical called dopamine, which makes you feel good. Getting that dopamine boost is part of the addiction process.
Tobacco dependence involves psychological as well as physical factors. You may developstrong, repetitive behaviors associated with smoking. You may smoke at certain times of the day or after a meal or in certain locations or under certain levels of stress. These behaviors and routines that you associate with smoking have to be addressed if you are to overcome your addiction to tobacco.
Risk factors
Anyone who smokes is at risk of becoming addicted to nicotine. Tobacco smokingis a behavior that often becomes established during adolescence. About 90 percent of smokers begin smoking before the age of 21, and many start before age 18.
The younger you begin smoking, the greater the chance that you'll become a heavy smoker as an adult. In 2004, 22 percent of American high schoolers said they were current smokers, as did nearly 12 percent of American middle-school-agechildren. While the rate of teen smoking has been declining since the 1990s, the decrease seems to have stalled in recent years. That's especially bad news because teenagers who smoke are more likely to use alcohol and other drugs.
Youngsters with two smoking parents are twice as likely to pick up the smoking habit themselves. And, children with friends who smoke are also more likely to try...