Smoking hurts most parts of your body, and new research is showing that it is hurting your brain, too. It appears to cause thinning to a part of your brain's cortex. The cortex is the outer layer of the brain involved in crucial functions such as memory, language, and perception.
The good news is that the research shows that stopping smoking helps to restore at least some of the thickness in the cortex.
These findings are from a study of 504 people, including people who currently smoked, former smokers, and people who had never smoked. Their average age was 73. Almost all had been examined as children in 1947 as part of the Scottish Mental Survey, in which children were given cognitive tests. All were able to give a complete smoking history and underwent a series of cognitive and medical tests and had brain MRI scans done. None had any evidence of dementia.
Current smokers were found to have a thinner cortex than those who had never smoked. Ex-smokers also showed a thinner cortex than people who had never smoked. The amount of smoking also had an effect, with people who had smoked more packs per day having a greater amount of thinning. But the greater the number of years since the last cigarette the more the cortex appears to have recovered some thickness.
"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," says the study's lead author Dr. Sherif Karama, assistant professor of psychiatry at McGill University in Montreal.
The cortex of the brain thins somewhat with age, but the association between smoking and cortical thinning was found to be independent of age.
The study was conducted at McGill, Harvard University, and the University of Edinburgh and was published in the journal Molecular Psychiatry.
