No Butts: smoking on the brain


It’s dirty, it stinks, it hurts your throat, it tastes bad, it kills your taste buds, your sense of smell, it’s harmful to others, it rots and stains your teeth, it gives you bad breath, it affects your breathing, it gives you wrinkles, it shortens your life, it makes you age faster, it clogs up your lungs, it wastes your money, it wastes your time, it stains your fingers, it strains your heart, it dictates your schedule… Sound like something you should be doing so often? But you knew all that already, didn’t you. Anyone want a smoke?

The neuroscience behind nicotine

Most of us know the dangers smoking poses to our bodies, but what about our brains? To our brains, nicotine appears identical to acetylcholine – a natural chemical messenger which carries signals between our nerve cells and different neural areas. There’s a special region of the brain, the ventral tegmental area (VTA), which is responsible for controlling and learning behaviours. It’s also packed with acetylcholine receptors.

With every drag of a cigarette, even if you’re not really enjoying it, in just six seconds the nicotine hit courses through your blood to the brain. Your brain thinks something great has happened and releases a rush of dopamine – an important neurotransmitter which basically tells your brain “that was EPIC; do it again”! Nicotine also triggers the release of endorphins, your body’s ‘happy drug’ and a natural painkiller. The next time you’re in a similar situation, cue the craving. Think Psych 101 – it is quintessential classical conditioning. As Lynne Dawkins notes, if you’re smoking 20 cigarettes a day – taking about 12 drags on each – you’re ‘positively reinforcing’ this behaviour 240 times a day and 87 600 times a year, at least. In fact, the more you smoke and the longer you do it for, you actually begin to alter your brain! That’s why you keep on needing more…

smoking MRI
smoking MRI

One of the reasons that cigarettes, and other drugs, are so addictive is because they tap into this ‘behavioural’ neural network. And because this is so ‘natural’ it most often occurs subconsciously. Ever lit up straight after you’ve put out your last cigarette? Forgotten you’ve just had one? Probably less than half of the cigarettes you’ve had were smoked deliberately. In fact, the ritualised nature of smoking has quite a few features in common with obsessive-compulsive disorder (OCD). This is why, despite your beliefs, hopes or intentions, efforts to stop smoking often fail.

Nicotine, though, is the least of your troubles. If you want to worry about something, take a look at the effects of tar and carbon monoxide, or some of the 7537 other chemicals in each cigarette. Yes. You read it. Seven thousand, five hundred and thirty seven. And you’re worried about the fat content of your milk?

Why can’t I quit?

Only 5% of smokers who quit ‘cold turkey’ are still smoke-free over 12 months later. And it’s not all your fault. Neuroscientist Joseph Mclernon ran fMRI scans on smokers and found that some of our brains are just more susceptible to smoking, and relapse, than others. Some of us are born with particularly rich neural networks in a part of the brain called the insula. This is the grey matter that regulates our cravings and communicates ‘cues’, like your first beer on a Friday or morning cup of coffee. The insula also connects to the motor areas; the bits of the brain that turn these cravings into action. It’s not that you don’t want to stop smoking, it’s just that you don’t. The most effective way to quit is by targeting the behaviour, but we’ll tell you exactly how to stop in our next post.

In Behavioural Science we call this an ‘intention-action gap’. I can desperately want to stop smoking, in fact it is all that I intend to do, but there are many subconscious and contextual forces wedging their way between what I intend to do and what I actually do.Colin Camerer has identified this intention-action gap on fMRI’s measuring activity in our motor - or ‘acting’ - areas. I can say that I will, or would, do something like turning down a drag of a cigarette – I can really, really believe it – but as the fMRI reveals, my brain knows that I am lying even before I do; it exhibits less activity in these ‘acting’ areas.

Even more fascinating, there is evidence that the pre-motor and parietal areas of our brains encode not only what we want to do and where we want to do it, but they also attach value to each intended action. This is most likely why you can only stop smoking if you really want to. If you intend to stop but are focusing on the deprivation or how hard it’ll be your brain automatically encodes less value in this idea. When it comes to crunch time it’ll quickly calculate this trade-off for you, ‘cut your losses’ and you’ll smoke instead. In fact, our brain is making these kinds of ‘cost analyses’ constantly, even when we’re not trying to make any kind of choice.

And if you’re a woman it gets a little bit worse. It’s to do with our hormones. It’s harder for the fairer gender to quit because oestrogen and progesterone trigger neural activity which sparks cravings and intensifies withdrawals.

old smoker
old smoker

Don’t stress about it

One of the biggest reasons that people smoke, and find it so hard to stop, is stress. Smoking kills. We know. We do it anyway. In fact, despite the fact that smoking causes over 6 million deaths a year, an estimated 1 billion people still smoke worldwide. So if it kills us, and we know that it does, then why do we still do it? It’s because knowing this makes us stress, and feeling stress makes us smoke, and smoking more when we know we shouldn’t be makes us even more stressed… and so the cycle goes. Scientists have found that warnings that emphasise our mortality – whether they’re about the tar lining your lungs or speeding down the tarmac – in fact make people behave more erratically. We don’t ‘arrive alive’ or refuse to light up. We speed up, take chances, smoke more.

Another reason the warnings of death, pictures of blackened lungs and cancers don’t scare us off is because they’re future focused. They’re far away. Whereas the side effects and ‘struggle’, no matter how tiny and pain-free by comparison, is right now. It’s not your fault, it’s ours. It’s evolutionary. We’ve survived as a species by being impulsive, trusting our instincts and focusing on the present. Behaviouralists call this present bias. The same hurdles to breaking the habit are the same problems that many of us encounter with saving and planning for retirement, or even the weekend! It’s hard to plan for a future that you might not have, so we’re hardwired to live in the moment. But, when it comes to things like saving and smoking, this ‘right here, right now’ attitude clearly works against us.

Physiologically, cigarettes actually raise blood pressure and make our hearts beat faster. These are symptoms of anxiety; your body is in distress, not de-stress. Smoking doesn’t calm you down, soothe your stress or solve your problem. It only relieves your craving for nicotine. And only for about half an hour. If you don’t want to feel stressed you’re going to have to do a whole lot more about it than smoke.

We smoke because we’re stressed, or over-stimulated, and we smoke to relax. How can the same thing have the opposite result half an hour later? We smoke when we’re bored, and we smoke when we need to concentrate… noticing a trend? There’s nothing magical about cigarettes that makes them a miracle cure-all for any and every situation. What’s a real marvel to behold is our brain’s ability to rationalise, to make excuses for our harmful behaviours.

smoke brain
smoke brain

Put your lighters up

Another contributing factor? Cognitive (over)lode. We’re bombarded with steady streams of information, decisions and distractions all day, both those we’re fully aware of and those our brain processes without our realising. Particularly in situations that require self-control and focus, we tend to wear down our willpower quite quickly. Scientists invited two groups of students to complete a study. Both were presented with a plate of radishes and another of chocolate. One group was told to eat whatever they liked, and the other only radishes. After putting them through their willpower paces, they were tasked with completing puzzles which, in reality, were unsolvable. The experimenters wanted to see whether testing people’s willpower in one situation would affect their self-control and determination in another, unrelated task. The group that had been able to eat as they pleased attempted the puzzles almost three times longer.

Yup, smoking changes not only our bodies and our brains but our personalities too. We become more irritable and aggressive without our ‘fix’. Our impulsive behaviours, lack of self-control and neurosis worsen in all aspects of our lives. A study conducted by Andrew Littlefield found that by quitting smoking you can change your entire personality.

Rising from the ashes

When you do to stop, within 20 minutes your blood pressure and heart rate return to normal. After 8 hours the nicotine in your body has reduced by over 93%. Twelve hours in: your oxygen levels have returned to normal and carbon monoxide is eradicated. After the first 24 hours your anxiety levels have peaked. Two days later and you’ll start to regain your sense of smell and taste, as well as feeling less irritability and anger…

Your body has the most incredible capacity to heal itself, and it all starts from that very last puff.

Nearly ¾ of smokers surveyed report wanting to stop. So how do you make the all-important change? Keep an eye out for our next post for a behavioural approach to the problem.

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