This Just In—Smoking Destroys Your Brain
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This Just In—Smoking Destroys Your Brain


This post was originally published on March 4, 2015.

Smoking sucks for so many reasons it almost feels useless to list them, but we’ll do so to add extra incentive for anyone out there who’s on the fence about quitting. Cancer of the lungs, the bladder, the pancreas, the gums, the throat, the esophagus, the cervix, the kidneys and the nose are some of the deleterious side effects, along with leathery skin, and of course increased risk for strokes and heart disease. It also makes for yellowed smiles, hardened plaque between your teeth and periodontal disease. And yes, smokers stink.

But scientists have uncovered yet another gnarly side effect of lighting up.

It’s All in Your Brain

Researchers at the University of Edinburgh studied a bunch of MRIs of smokers; after close scrutiny, the scans revealed smokers have thinner brain cortices. If you weren’t paying attention in eighth grade science (or have since destroyed some brain cells), the brain cortex is a thin layer of tissue that surrounds the brain mass. Unfortunately for smokers, this part of your brain plays a vital role in high-level duties like language, consciousness and memory, all of which decline as the brain ages.

Helming the study was Ian Dreary, director of Centre for Cognitive Ageing and Cognitive Epidemiology at the University of Edinburgh.

“It is important to know what is associated with brain health in older age,” Dreary says. “From these data we have found a small link between smoking and having thinner brain grey matter in some regions.”

The paper published after the study’s conclusion indicates smoking exacerbates thinking, which might be the underlying causal factor of the thinning cortex, although scientists are still, er, thinking about the link. Perhaps that’s the reason we light up when we’re in an extra stimulating conversation or need to solve a complex problem—our thinking gets all hyped up. Who knew those Marlboro Lights could lead to early senility and loss of grey matter?

The Guinea Pigs

The smokers who took part of the study were part of a group called the Lothian Birth Cohort (yeah, it sounds a bit creepy, like some secret society of sociopathic midwives).  All these folks—260 females and 244 males—were born in 1936 and signed up to participate in the Scottish Mental Survey of 1947, a study that tested intelligence levels of children. With IQ data still on hand from the 1947 test results, scientists could compare differences in cognition due to ageing in the participants 68 years later.  In addition to the general cognitive tests, the participants, now 79-years-old, were divvied up in three groups according to their smoking habits—those who never smoked, those who quit smoking and those who currently smoke.

The Good News…and the Bad

Current smokers had the thinnest cortices of the bunch, those who had never smoked had the thickest and smokers who gave up cigs for a significant period of time but ended up falling off the wagon had thicker brain cortices than their counterparts who had just quit. This gave the researchers some hope that perhaps the effect of smoking on the brain might be reversible.

Unfortunately, much more research needs to be done to determine that the brain can actually fully recover from the damage incurred after inhaling all that CO2, tar and tobacco. Until further notice, it might be best to play it safe and assume the thinning brain cortex is irreversible and put out our cigs out for good.

Of course, easier said than done.

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About Author

Tracy Chabala is a freelance writer for many publications including the LA Times, LA Weekly, Smashd, VICE and Salon. She writes mostly about food, technology and culture, in addition to addiction and mental health. She holds a Master's in Professional Writing from USC and is finishing up her novel.