Why Is Nicotine Addictive? You Asked Google--Here's the Answer
Animals, including human animals, often find themselves in a state of desire. Desire, the felt motivation to pursue a goal, is how nature gets us to go after the things we need: food, sex, shelter, social status, cigarettes. Wait a minute … cigarettes?
Like many other chemical candidates for the wayward human appetite, tobacco attracts. We desire it, despite its bad press. And as a result, it is one of the worst public health disasters the world has ever encountered.
Tobacco contains nicotine, which is “physically addictive” – meaning we experience a degree of relief and sometimes pleasure when we take it, and when we stop we experience physical discomfort. The same is true of heroin, of course, but that infamous drug is less deadly than nicotine.
The pleasure provided by nicotine is complicated. Nicotine molecules find their way to receptors (little harbours) on several types of brain cells. The first type processes acetylcholine , one of the brain’s main neurochemicals. Acetylcholine makes us more alert and focused, it powers consciousness itself – so nicotine enhances our sense of being alive, if only slightly. The second type of brain cell colonised by nicotine processes dopamine , the neurochemical that causes us to feel attraction and anticipation. Dopamine is a well-known culprit in all kinds of addictions. It’s been linked with pleasure conventionally, but its main function is to promote desire and goal pursuit rather than pleasure per se. In fact, nicotine receptors are scattered all over the brain, and they turn up the tap on other neurochemicals, in charge of every brain state from arousal to relaxation.
Nicotine makes us feel good in subtle and complex ways, but withdrawal makes us miserable in subtle and complex ways
As with other addictive drugs, the comforts of nicotine are outweighed by the discomforts attendant on quitting. All those receptors in all those regions grow accustomed to their nicotine diet after several months. They adjust to that diet, so they are relatively starved when it’s suddenly withdrawn. The positives rebound into proportional negatives – and we feel that backlash in our bodies as they receive distress signals from our brains. Just as nicotine makes us feel good in subtle and complex ways, nicotine withdrawal makes us miserable in subtle and complex ways. That may be why, compared to other drugs, nicotine is the hardest to kick. Gene Heyman , an American addiction researcher, compiled epidemiological data on the average time to quit several drugs, and here are his surprising findings:
With the onset of dependence as the start date, half of those ever addicted to cocaine had quit using this drug at clinically significant levels by year four, and the half-life for marijuana dependence was six years. In contrast, alcohol and cigarette dependence had much longer half-lives. For alcohol, the 50% remission mark was not reached until year 16, and for cigarettes, it took on average 30 years for dependent smokers to quit. (GM Heyman, Quitting drugs: Quantitative and qualitative features. Annual Review or Clinical Psychology, 2013)
Thirty years (on average)! More than seven times longer than it takes to quit cocaine. That would be a really good reason not to start.
Physical addiction, with its attendant pleasures and risks, is just one limb of a much bigger elephant, and it takes quite a few blind men to get the whole picture. My research and writing has focused on the psychological side of addiction instead. Psychological addiction is far more insidious than physical addiction. For one thing it explains why people continue to “relapse” long after they are physically free of a drug. It also explains why drugs that don’t cause withdrawal symptoms can easily addict. These include cocaine, marijuana and alcohol (which only causes rebound symptoms when large quantities are consumed for lengthy periods). Then there are those addictions that don’t involve substances at all: gambling, sex addiction, porn addiction, internet addiction ( now classed as a psychiatric ailment ) and of course eating disorders, which can be harder to kick than heroin. So how does addiction work if it doesn’t rely on physical dependency?
The first thing to realise is that psychological addiction is physical too: psychological states depend on brain states, and the brain is obviously a physical entity. Second, the psychological state of craving is the lynch pin of relapse. As any addict will tell you, persistent craving is like an acid that eats through resolve and good sense. So how does craving work, and what sort of brain mechanisms support it? Craving is just intense, focused desire, and the neural engines of desire have been fine-tuned over hundreds of millions of years of evolution. We need desire in order to survive. And we experience craving ubiquitously: when we fall in love, watch our favourite team get the ball, smell someone’s barbecue, or pray to our preferred deity. Unlike withdrawal symptoms, craving is natural; but craving can easily get stuck, and that’s the problem when it comes to addiction.
Each time that cycle of wanting, getting and losing is repeated, a network of connections is reinforced in your brain
Craving, whether for a person, a team, a smoke or an illicit drug, becomes an entrenched habit through repeated cycles of desire, acquisition and loss. You want it, you get it, then it’s gone. Your team loses, your lover storms off and drugs run out. (A nicotine rush is remarkably short-lived, which might help explain why smoking digs its ruts so deeply.) Each time that cycle of wanting, getting and losing is repeated, a network of connections is reinforced in your brain. Acute focus, fuelled by desire, grows connections (synapses) among the brain cells devoted to the thing you can’t help wanting. With each repetition, that synaptic cluster is enriched: millions of new synapses fill in the gaps, and the synaptic networks underlying other goals dissipate with disuse. Then, when a reminder or “cue” pops up, that now-familiar synaptic configuration is activated like a cluster of Christmas lights. That’s when you can’t think of much else or wish for much else until you get it. That’s craving.
Because persistent craving (and the corresponding loss of control) relies on brain changes (synaptic reconfigurations), addiction experts all over the world have come to define addiction as a brain disease. Medical, psychiatric and rehab authorities like to say that addiction hijacks the brain . And their solution is more drugs, 12-step meetings, huge price tags for residential rehabs and not much else.
Rather than a disease, I see addiction as the outcome of a brain doing what it’s supposed to do: seek pleasure and relief in a world that isn’t cooperating. Other researchers also recognise that addiction grows best in a vacuum, in environments devoid of other, more wholesome rewards, such as prosperity, community, close interpersonal relationships and self-esteem. Desire can get stuck in a lot of places: in loving and caring for your kids or your pet, gourmet cooking, stamp-collecting, you name it. Or it can get stuck on drugs, including nicotine, when that empty feeling comes around again.
The brain changes that underlie addiction indicate a deep and entrenched history of learning, not a disease. So, to fight addiction, we have to address the feelings and the conditions that send people searching for short-lived rewards with long-term consequences. That’s how I portray addiction in The Biology of Desire , which is subtitled Why Addiction is Not a Disease. The book links biographies of five likeable addicts with the facts about what’s going on in their brains. And it follows them as they develop, move on to other goals that are incompatible with addiction, and leave their potions and poisons behind. Brain change is the foundation of all learning: it doesn’t equal brain disease. And luckily the brain can keep changing, with some work and some practice – as when smokers jettison that last pack and move on with their lives.