Why Is It So Hard to Quit Smoking?
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The Science Behind Quitting Smoking

Studies have shown that for every 100 people who try to quit without any aids, 90 will relapse. Most people who recommence smoking will do so within the first three months after quitting, but the risk for relapse remains high even throughout the first year. Even with the aid of nicotine replacement devices, such as patches, gums, or nasal sprays, the relapse rate remains at 80%.

Smoking is one of the leading causes of preventable illness in the world today. Consequences include cancer, heart attack, lung disease and more.

Most people who smoke understand the serious health risks involved. Only a potently addictive substance would cause people to continue a habit that seriously affects their health even in the face of the strongest medical advice to quit.

So, why is it so hard to quit smoking?

Nicotine and Addiction

Nicotine is the main addictive ingredient in cigarettes. Studies indicate nicotine is as addictive as heroin or cocaine.

All drugs of addiction activate areas of the brain that form the mesolimbic pathway, also called the dopamine reward pathway. This pathway is very old, located deep in the center of the unconscious brain, and is associated with primal instincts, such as food, drink, sex, social interactions and fleeing predators.

Activation of the pathway heightens memory of the event (such as finding food) and all the features and cues surrounding it, so it can be repeated again. Drugs of addiction activate this primal pathway; they cause potent cravings that frequently win against the brain’s conscious desires to quit.

Not all smokers become addicted to nicotine, but the vast majority do. Adolescents seem to be the most vulnerable to forming a nicotine addiction and, unfortunately, adolescence is the time when many people first experiment with cigarettes. People with certain genes may also be more vulnerable to forming a nicotine addiction.

Positive Sensations

Nicotine is a stimulant; it can create pleasurable feelings and increase attention, thinking, memory and learning. Paradoxically, it can also have a relaxing effect and alleviate anxiety, depression and pain.

Smoking also reduces appetite and increases the metabolic rate. Some people, particularly women, smoke to help lose weight. It is the positive effects of smoking that cause many people to continue the habit after trying it for the first time.

Withdrawal Effects

Negative sensations are felt within a few hours after finishing a cigarette. Withdrawal symptoms include irritability, anxiety, depression, restlessness, trouble sleeping, problems with memory and concentration, and an increase in appetite.

These withdrawal effects peak within a few days to a week after the last cigarette and may not disappear for two to four weeks. Some effects, such as mild depression and increased appetite, may persist for months.

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Although the positive aspects of smoking may initially reinforce the habit of smoking, it is the withdrawal effects that make it hardest to quit.


With repeated use, the body adjusts to the nicotine and increasing doses are required to produce the same effects. Thus, cigarette use increases over time, with a person increasing the number of cigarettes smoked throughout the day. The greater the cigarette use, the harder it is to quit.


Nicotine heightens all the memories and cues associated with smoking, such as having a cigarette with coffee, during work breaks, at social gatherings or after a fight. It also includes the sight, smell and taste of tobacco and tobacco paraphernalia, like ash trays and packaging.

Not only is the act of having a cigarette self-rewarding, but the habits associated with smoking are also reinforced. This means a smoker will associate particular rituals with a pleasurable experience and will seek to replicate those circumstances again.

Or if not planning to smoke, placed in particular circumstances, such as with other smokers, the desire to smoke will be very strong.

Nicotine Replacement Products

If nicotine makes smoking addictive, why are nicotine replacement products not enough?

There are several reasons for this. When nicotine is smoked, it readily passes into the body. Smoking delivers a faster and a higher hit of nicotine compared to using nicotine replacement devices.

Once smoked, nicotine reaches the brain in seven to 19 seconds. It is then rapidly removed from the body. This means the smoker can easily control the amount of nicotine in the body.

Nicotine replacement products, such as nasal sprays, gums and patches, cause a more gradual and sustained entry of nicotine into the body. Smokers addicted to nicotine will be drawn, through cravings, to the instant gratification and higher levels of nicotine from actual smoking.

However, studies have shown that even when nicotine is injected directly into the blood, delivering a rapid and high nicotine dose, it does not satisfy people in the same way that smoking does. There are a couple of reasons for this.

Tobacco contains many chemicals. While nicotine is the most potently addictive ingredient, there are other products in tobacco that are either addictive themselves or reinforce the addictive effects of nicotine.

Scientists are still trying to understand what these other products are and how they work. One product, norcicotine, is formed when a by-product of nicotine joins with another chemical in tobacco.

Norcicotine is not as potent as nicotine, but it adds to the effects of nicotine. Acetaldehyde in tobacco also has reinforcing effects, perhaps more so in adolescents.

Other ingredients have also been shown to increase the addictiveness of tobacco. Thus, pure nicotine does not have exactly the same addictive effects as tobacco.

Also, nicotine heightens attention to all aspects of smoking, including the sensual and physical aspects of smoking, such as the rituals, smell, sensation and taste. The physical aspects of smoking become rewarding in themselves, separate from the nicotine hit.

These aspects are not satisfied by a nicotine replacement product, so a smoker will still crave the actual sensation of smoking.

Smoking is a drug of addiction. Most people do not manage to quit on their first attempt, but it gets easier with every attempt. Nicotine replacement is not the sole answer, but it can help.

Like any drug of addiction, you will have more success if you seek help.