April 17, 2013   Contributing Author: Guy Slowik, FRCS

A smoking addiction means a person has formed an uncontrollable dependence on cigarettes to the point where stopping smoking would cause severe emotional, mental, or physical reactions.

Everyone knows that smoking is harmful and addictive, but few people realize just how risky and addictive it is. Chances are that about one in three smokers who do not stop will eventually die because of their smoking. Some will die in their 40s, others will die later.  On average, they will die 10 to 15 years earlier than they would have died from other causes.

Most smokers want to stop and do indeed try, but only one in three succeeds in stopping permanently before age 60.  By this time, much harm may occur to the body - some of it irreversible.  Those who eventually quit smoking usually try to stop two or three times before they're successful.   Only 2.5 percent of smokers successfully quit each year.

The reason why so many people fail to stop is because they are addicted.  Being addicted does not mean that you cannot stop - only that it is likely to be difficult.  Anyone can succeed if he or she goes about it in the right way.  How you stop - and, especially, when you stop - is a very personal matter.  Only you know what you have to give up, and how the benefits of smoking can be weighed against the benefits of stopping.

Harassment and pressure from others, who do not understand, is often unhelpful.  You will only stop when you have made a firm decision.  When you do make up your mind, however, you can succeed, regardless of how addicted you may be.   If you stop smoking before or during middle age (age 35 to 50), you will avoid about 90 percent of the lung cancer risk.  If you are currently middle-aged, you are also more likely to succeed in quitting now than when you were younger.

Why Is Smoking Addictive?  Nicotine is the drug in tobacco that causes addiction.  It is absorbed and enters the bloodstream, through the lungs when smoke is inhaled, and through the lining of the mouth (buccal mucosa) when tobacco is chewed or used as oral snuff, or for non-inhaled pipe and cigar smoking.  It is also absorbed through the nose from nasal snuff, which was popular in the 18th century.

Nicotine is a psychoactive drug with stimulant effects on the electrical activity of the brain.  It also has calming effects, especially at times of stress, as well as effects on hormonal and other systems throughout the body.  Although its subjective effects are less dramatic and obvious than those of some other addictive drugs, smoking doses of nicotine causes activation of "pleasure centers" in the brain (for example, the mesolimbic dopamine system), which may explain the pleasure, and addictiveness of smoking.

Smokers develop tolerance to nicotine and can take higher doses without feeling sick than when they first started smoking.  Many of the unpleasant effects of cigarette withdrawal are due to lack of nicotine and are reversed or alleviated by nicotine replacement (for example, nicotine chewing gum or the nicotine patch).  As with other addictions, it is difficult to give up smoking, and without help most smokers fail despite trying many times.  Even after stopping successfully for a while, most relapse within 2 to 3 months.  More alarming perhaps than the strength of the addiction is the ease with which it develops.  

Although teenagers often start smoking for psychosocial reasons, the effects of nicotine soon gain control.  Studies show that tobacco use usually begins in early adolescence, and those who begin smoking at an early age are more likely to develop severe nicotine addiction than those who start later.  Each day, more than 4,800 adolescents smoke their first cigarette, and 42 percent of them go on to become regular smokers.

Is Smoking A Physical Addiction? Smoking is a physical addiction that produces a "chain reaction" in the body:  Nicotine acts on receptors normally used by one of the main neurotransmitters in the brain and nervous system (acetylcholine).  Neurotransmitters are the "chemical messengers" released by nerve cells to communicate with other cells by altering their electrical activity. The body responds to nicotine at these receptors as if it was the natural transmitter (acetylcholine) and the activity and physiological functions of many brain systems are altered.

With repeated nicotine dosage the body adapts to what it regards as extra acetylcholine in an attempt to restore normal function.  One way it does this is to grow more acetylcholine receptors. Thus nicotine induces structural as well as functional changes in the brain of smokers.  When nicotine is suddenly withdrawn, physiological functions in the brain and other parts of the body are disturbed.  This is known as withdrawal syndrome.  It takes time for the body to readjust to functioning normally without nicotine.

Social And Psychological Factors

In all drug addictions, psychosocial factors determine the initial exposures.  Addiction may subsequently develop if the drug has pharmacological effects that people like or find rewarding.  It is essentially a learning process:  Learning when, where, and how to take the drug to get the most rewarding effects.  The taste, smell, visual stimuli, handling, and other movements that are closely associated with the rewarding pharmacological effects gradually become rewarding themselves.  This is known as conditioning.  The situations and activities associated with smoking, together with the smoker's mood and psychological state at the time, also become linked with its rewards and with the relief of withdrawal.  They come to serve as signals or triggers for the urge or craving for nicotine's effects (for example, after meals, with coffee or alcohol, when meeting people, working, talking on the phone, and when anxious, angry, celebrating, or having a well-earned break, and so on).  Triggers that bring on the urge to smoke are numerous because smoking can take place in so many situations.

Smoking As A Drug-Taking Activity

Most smokers absorb sufficient nicotine to obtain pharmacological effects.  The modern cigarette is a highly effective device for getting nicotine to the brain.  The smoke is mild enough to be inhaled deeply into the lungs.  Due to the large surface area of the lungs, nicotine is absorbed rapidly into the bloodstream and reaches the brain within 7 seconds - more rapidly than after an intravenous injection.   In this way the smoker gets a small intravenous-like shot of nicotine after each inhaled puff:  20 cigarettes a day, each puffed 10 times, comes to more than 70,000 "shots" per year.  On average, smokers take in about 1 milligram (mg) nicotine from each cigarette, although some take 2 milligrams or more while others are satisfied with 0.5 milligrams or less.  By altering puff-rate, puff-size and amount of inhalation, smokers unconsciously regulate their nicotine intake to their individually preferred levels, which are kept fairly constant from one day to the next.  The nicotine yields of the cigarettes make little difference.  By puffing harder, inhaling more deeply, and smoking down to the tip, smokers can get 2 milligrams of nicotine or more from a low-yield cigarette with an official machine-smoked yield of only 0.6 milligrams.  Cigarette smokers literally do have fingertip control over the delivery of nicotine to their brain.

Facts About Smoking And Addiction

Smoking-related illnesses cause about 440,000 deaths each year in the U.S.  Smoking is responsible for 87 percent of lung cancers and also causes most cases of emphysema (COPD) and chronic bronchitis.   Tobacco use, especially smoking, is the number one cause of preventable disease and death in the U.S.  Cigarettes contain at least 54 distinct cancer-causing chemicals.  Nicotine is as highly addictive as heroin and cocaine.  Approximately 80 percent of adult smokers started smoking before age 18.

Most people try to quit smoking several times before they are successful.  And, only 2.5 percent of smokers successfully quit each year. T he benefits of quitting smoking begin to occur within 20 minutes after the last cigarette smoked.  A person who stops smoking will have the same risk of heart disease and death 15 years after quitting as someone who has never smoked.

Secondhand smoke is known to cause cancer and is responsible for approximately 3,000 lung cancer deaths in nonsmokers each year.