How Smoking Damages Your Brain

Smoking has long been linked to heart disease and COPD. Now, the science shows that smoking also raises your risk for strokes, memory loss, and even dementia.

The Surgeon General first raised the alarm about the dangers of cigarette smoking nearly 60 years ago. Yet, the problem remains; the tobacco habit has been killing almost half a million Americans every year, according to the Centers for Disease Control and Prevention.

Smoking has long been linked to a myriad of health problems, from lung cancer and heart disease to chronic obstructive pulmonary disease and certain birth defects. Evidence has accumulated in recent years indicating tobacco hits the brain hard, too.

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Brain aging

Brain scans can reveal how much the cortex — also called the gray matter that processes information and is critical for thinking skills, memory, and learning — is shrinking, a sign of possible dementia. It happens to us all, with age, but it appears to happen faster in smokers.

One large team of researchers drew upon data from male twins who had served in the U.S. military, comparing their smoking history around the age of 40 with brain imaging results at 56. They could also compare one twin to another. They concluded that the more the men smoked at 40 the more likely they were to show accelerated signs of brain aging at age 56.

Another study found that, compared to non-smokers, at age 50 current smokers showed more dementia-related brain changes. A useful finding was that people who also drank were hit harder.

Other research concluded that the longer you smoke, the higher your risk of cortex shrinkage.

In fact, according to earlier research, smoking hits your brain harder than high blood pressure, high cholesterol, or obesity. In that study, smokers consistently scored lowest on three objective memory tests that measured attention, mental speed, and visual scanning.

Brain aging isn’t the same as dementia

But several studies have associated smoking with an increased risk of a diagnosis of dementia. Deborah Barnes, a mental health researcher at the San Francisco VA Medical Center, estimates that nearly 14 percent of Alzheimer's disease cases worldwide could be attributable to smoking, one of several modifiable risk factors known to influence that dreaded disease.

“What’s exciting is that this suggests that some very simple lifestyle changes, such as increasing physical activity and quitting smoking, could have a tremendous impact on preventing Alzheimer’s and other dementias in the United States and worldwide,” said Barnes, an associate professor of psychiatry at the University of California, San Francisco (UCSF).

Smoking and stroke

By contributing to cardiovascular disease, smoking is known to raise the risk of blood clots that cause brain-damaging and potentially deadly strokes. Research published in the prestigious New England Journal of Medicine shows that smokers are twice as likely to die of stroke, also known as a “brain attack,” compared to non-smokers.

How do cigarettes do all this harm?

One clue is that a compound known as NNK in tobacco may trigger brain cell damage. NNK causes inflammation by provoking immune cells in the central nervous system to attack healthy brain cells.

If you are thinking about quitting, there’s good news, too.

In one study, researchers examined 244 men and 260 women, whose average age was 73. The group included smokers, ex-smokers, and non-smokers.

“We found that current and ex-smokers had, at age 73, many areas of thinner brain cortex than those that never smoked. Subjects who stopped smoking seem to partially recover their cortical thickness for each year without smoking,” the study’s lead author Sherif Karama, assistant professor of psychiatry at McGill University, said.

That didn’t mean that quitting smoking allowed brains to recover quickly — or completely. MRIs revealed that even after quitting cigarettes over 25 years ago, those research subjects who had once been heavy smokers still had thinner cortices than those who had never smoked.

The researchers concluded that the sooner a smoker stops lighting up, the better the odds of recovery, although the damage can persist for many years.

Bottom line: It’s a no-brainer that anyone who is still smoking should quit. You have many options to help you quit. Here’s a summary of some of the resources and strategies that are proven to help.

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