Nicotine dependence

Symptoms

In some people, using any amount of tobacco can quickly lead to nicotine dependence. Symptoms of addiction include:

• You can't stop smoking. You've made one or more serious, but unsuccessful, attempts to stop.
• You experience withdrawal symptoms when you try to stop. Your attempts at stopping have caused physical and mood-related symptoms, such as strong cravings, anxiety, irritability, restlessness, difficulty concentrating, depressed mood, frustration or anger, increased hunger, insomnia, and constipation or diarrhoea.
• 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 recreational activities in order to smoke. You may stop going to smoke-free restaurants or stop socializing with certain family members or friends because you can't smoke in these situations.

Causes

Nicotine is the chemical in tobacco that keeps you smoking. It can be as addictive as cocaine. It increases the release of brain chemicals called neurotransmitters, which help regulate mood and behavior. One of these neurotransmitters is 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. Behaviors and cues that you may associate with smoking include:

• Certain times of the day, such as with morning coffee or during breaks at work
• After a meal
• Drinking alcohol
• Certain places or friends
• Talking on the phone
• Stressful situations or when you're feeling down
• The smell of a cigarette
• Driving your car

To overcome your dependence on tobacco, you need to deal with the behaviors and routines that you associate with smoking.

Risk factors

Anyone who smokes is at risk of becoming dependent on tobacco and nicotine. Most people begin smoking during childhood or adolescence.

The younger you begin smoking, the greater the chance that you'll become a heavy smoker as an adult. Children with two parents who smoke are twice as likely to become smokers. Children with friends who smoke also are more likely to try cigarettes.

Other factors that influence nicotine dependence include:

• Genetics. The genes you inherit play a role in some aspects of nicotine dependence. For example, the likelihood that you will start smoking and keep smoking may be partly inherited. Some people experiment with smoking and don't experience pleasure, so they never become smokers. Other people develop dependence very quickly. Some "social smokers" can smoke just once in a while, and yet another group of smokers can stop smoking with no withdrawal symptoms. These differences can be explained by genetic factors that influence how receptors on the surface of your brain's nerve cells respond to nicotine.
• Depression, other mental illness and substance abuse. People who have depression, schizophrenia and other forms of mental illness are more likely to be smokers. Smoking may be a form of self-medication for these disorders. People who abuse alcohol and illicit drugs also are more likely to be smokers.

Complications

When you inhale tobacco smoke, you ingest numerous chemicals that reach most of your body's vital organs. Tobacco smoke contains more than 60 known cancer-causing chemicals and more than 4,800 other harmful substances.

Smoking harms almost every organ of your body. More than half the people who keep smoking will die because of it. The negative health effects include:

• Lung cancer and other lung diseases. Smoking causes nearly 9 out 10 of lung cancer cases, as well as other lung diseases, such as emphysema and chronic bronchitis. Smoking also makes asthma worse.
• Heart and circulatory system problems. Smoking increases your risk of dying of cardiovascular disease, including heart attack and stroke. Smoking 15 cigarettes a day doubles your heart attack risk. Even smoking just one to four cigarettes daily increases your risk of heart disease. If you have cardiovascular illness or heart failure, smoking worsens your condition. However, stopping smoking reduces your risk of having a heart attack by 50 percent in the first year.
• Other cancers. Smoking is a major cause of cancers of the oesophagus, larynx, throat (pharynx) and mouth and also is related to cancer of the bladder, pancreas, kidney, cervix, stomach, and some leukemias.
• Physical appearance. The chemicals in tobacco smoke can change the structure of your skin, causing premature aging and wrinkles. Smoking also yellows your teeth, fingers and fingernails.
• Infertility and impotence. Smoking increases the risk of infertility in women and the chance of impotence in men. Pregnancy and newborn complications. Mothers who smoke while pregnant face a higher risk of miscarriage, preterm delivery, decreased birth weight and sudden infant death syndrome (SIDS) in their newborn. Low birth weight babies are more likely to die or have learning and physical problems.
• Cold, flu and other illnesses. Smokers are more prone to respiratory infections, such as colds, flu and bronchitis, than are nonsmokers.
• Diabetes. Smoking increases insulin resistance, which can set the stage for the development of type 2 diabetes. If you have diabetes, smoking can speed the progress of complications such as kidney disease.
• Impaired senses. Smoking deadens your senses of taste and smell, so food isn't as appetizing as it once was.
• Risks to your family. Spouses and partners of smokers have a higher risk of lung cancer and heart disease, compared with people who don't live with a smoker. If you smoke, your children will be more prone to sudden infant death syndrome, asthma, ear infections and colds.

Diagnosis

There are no physical tests to determine the exact degree to which you're dependent on nicotine. Your doctor may assess the degree of your nicotine dependence by asking you questions or having you complete a questionnaire. The more cigarettes you smoke each day and the sooner you smoke after awakening, the more dependent you are. Knowing your degree of dependence can also help determine the correct dose of a nicotine replacement medication.

References

http://emedicine.medscape.com/article/287555-overview

http://www.healthline.com/health/nicotine-and-related-disorders

http://www.cdc.gov/tobacco/data_statistics/fact_sheets/cessation/quitting/

https://www.drugabuse.gov/publications/research-reports/tobacco/nicotine-addictive