Quite simply, smoking addiction is caused by the nicotine in tobacco and how the nicotine enters the bloodstream and brain of a smoker. Just as oxygen passes into the lungs and then into the blood, so the smoke and nicotine pass into the lungs and blood of a smoker, and then pass through the bloodstream into the brain. Once in the brain, smoking addiction is established by how the nicotine acts with the brain, creating a physiological change and dependency on the nicotine. This is typically reinforced through social and psychological conditioning in which the action of smoking becomes further associated with enjoyment and relaxation.
Smoking addiction literally begins with the very first inhalation of a cigarette or similar tobacco product. Nicotine is contained within the tobacco leaf, and is a carcinogenic substance that acts as the tobacco’s natural defense against insects and other potential infestation. The nicotine passes from the tobacco through smoke into the lungs of a smoker, or into the mouth of a tobacco chewer or non-inhaling pipe or cigar smoker, and then into the blood stream. Once in the bloodstream, the nicotine quickly moves to the brain. Even if a person’s first inhale of a cigarette is accompanied by coughing, nausea, and other potential unpleasantness, within about 10 seconds the nicotine has reached the brain and triggered an enjoyable response.
In a person’s brain, nicotine fits to neural receptors that are typically used by a neurotransmitter called acetylcholine. Acetylcholine is responsible for a number of different neurological chemical processes in the brain, including the release of dopamine and similar pleasure center stimuli. This means that when the nicotine reaches a person’s brain, it triggers an immediate pleasure response. Continued smoking addiction becomes established as the brain attempts to deal with the flood of nicotine by creating many more acetylcholine receptors, which the nicotine is then able to utilize.
The increase in receptors, however, often requires greater amounts of nicotine to trigger the pleasure response. At this point, a person has succumbed to smoking addiction and his or her brain has now made real physiological changes to continue dealing with nicotine. This is why quitting often is accompanied by physical and psychological issues such as headaches, nausea, irritability, and mood swings. While quitting, a person is literally starving his or her brain of a chemical that the brain has come to expect as a regular part of daily operation.
Smoking addiction is typically further reinforced through psychological and social conditioning, established by the association of smoking with enjoyable activities. When a person smokes after each meal, he or she conditions his or her body to expect that chemical and neurological rush after the meal. Once conditioned, the person will naturally expect to feel the physical affect of nicotine in his or her system after every meal. This is why smoking addiction is so often a social and mental issue, as well as physical, because a person teaches his or her body to associate the chemical response with other activities.