Think you don’t really smoke for nicotine?
Now I agree that there may be a few smokers out there who are really not inhaling very much nicotine, or can go a week or more without smoking and not miss it at all. But these are a tiny minority of smokers (fewer than 5%) and it’s possible to identify them with a few questions about their cigarette consumption and experiences when not smoking (see prior posts). But for more than 95% of the smokers reading this article, the primary reason for smoking is for the psychological effects of the drug, nicotine, provided by smoking.
Every time a smoker inhales a puff of cigarette smoke, the smoke is carried to the lungs, absorbed directly into the blood and carried via the arterial circulation to the heart and the brain. That clump of smoke contains a high concentration of nicotine, which reaches the brain within 15 seconds of each puff. On reaching the brain, nicotine binds to certain types of receptors (nicotinic acetylcholine receptors), which then cause a cascade of other effects, including the release of the “reward neurotransmitter” – dopamine, in some of the parts of the brain that are particularly sensitive to reinforcement and emotional regulation. Other effects include a mild stimulant effect, that can be measured as an increase in heart rate, and a speeding of the brain’s electrical activity. This effect is also associated with a slight improvement in focused attention and tasks like driving late at night. We know that all of these (and some other) effects are caused by nicotine because they don’t occur when people smoke cigarettes that don’t contain nicotine, and likewise they don’t occur in laboratory rats given placebo (no drug) injections rather than nicotine.
Some of these effects are quite subtle, particularly after the first cigarette of the day. The smoker is typically not aware that their brain waves have speeded up, and they don’t usually experience a very noticeable “high” or intoxication that can be caused by numerous other addictive drugs. But the reinforcing effect on the brain and the occasionally noticeable feeling of satisfaction or “buzz” from the cigarette, which are caused directly by nicotine, become associated with the behavior of opening a cigarette pack, lighting a cigarette, inhaling the smoke and feeling that hit at the back of the throat as it goes down to the lungs. You may have heard of the famous experiments conducted by Ivan Pavlov, the Nobel Prize-winning Russian scientist at the beginning of the 20th century. He was initially interested in studying the functioning of the gastric system in dogs. This involved ringing a bell, presenting the dog with some food and then measuring the amount of saliva produced by the dog in response to the food. Pavlov quickly noticed that while a new experimental animal would initially only salivate when given food, after a few pairings of the bell with the food, the dogs would salivate simply in response to the bell. This very fundamental type of learning is called “classical conditioning” and it helps us to understand why smokers say they believe they really just enjoy the ritual or the feeling of the smoke hitting the back of their throat. The ritual of opening the pack, and the sensation of the smoke hitting the back of the throat were not satisfying the first time you did them. But after smoking a few packs, that ritual is like the bell for Pavlov’s dogs. It is a perfect predictor that in a few seconds, nicotine will reach the brain, and stimulate the release of dopamine in the reward center. Just as Pavlov’s dogs really get to like the sound of the bell, and start salivating as soon as they hear it, so the smoker really gets to like the ritual of lighting a cigarette. The main difference is that unlike Pavlov’s dogs, people can ring the bell themselves (by buying a pack and lighting up). The whole ritual becomes self-reinforcing, and this is strengthened by the fact that when a smoker goes for a day or two without the ritual, they start to experience unpleasant withdrawal symptoms, that are then relived by smoking. The ritual or habit is strengthened to the point that the smoker has cravings and urges to smoke when they havn’t done so for a few hours. This is an addiction, and happens to be caused by the effects of nicotine.
If you really don’t think it’s the nicotine then try switching to a brand of nicotine-free (zero nicotine, not “low”) cigarettes for a week. They provide the whole ritual, minus the nicotine. In fact you may find that at first the nicotine-free cigarettes help reduce cravings and seem to fulfill the same needs as your regular cigarettes. But within the first week or so the “extinction” process will take place – just as happened with Pavlov’s dogs if he kept ringing the bell but didn’t follow it up immediately with food. The dog learns that the bell is no longer associated with food and salivates less and less over time when the bell is rung. After a while the smoker realizes that these nicotine-free cigarettes aren’t doing it for them any more. By that time they are also experiencing nicotine withdrawal symptoms. This is why almost no smokers smoke nicotine-free cigarettes. They are missing the key ingredient.
As my former PhD supervisor, Professor Michael Russell, once put it, “If it wasn’t for the nicotine in cigarettes, people would be no more likely to smoke than to blow bubbles.”