Smoking is bad for the brain
16:44 10 December 2004
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Mental health department, University of Aberdeen
Scottish Mental Survey, Scottish Council for Research in Education
Given the wealth of evidence that smoking damages your health, you would have to be stupid not to kick the habit. Now a study suggests this could be a self-fulfilling prophecy, because smoking reduces your IQ.
Lawrence Whalley at the University of Aberdeen and colleagues at the University of Edinburgh, both in the UK, looked at how the cognitive ability of 465 individuals, approximately half of whom were smokers, changed over their lifetime and whether this related to their smoking habits.
They had all been tested in 1947 at age 11 as part of the Scottish Mental Survey, which made no distinction between smoking habits. They were tested a second time between 2000 and 2002, when they were 64 years old.
Smokers performed significantly worse in five different cognitive tests than did both former smokers and those who had never smoked. When social and health factors such as education, occupation and alcohol consumption were taken into account, smoking still appeared to contribute to a drop in cognitive function of just under 1%.
A link between impaired lung function and cognitive ageing has long been suspected, though the mechanism is unclear. One possibility is that smoking subjects the vital organs, including the brain, to oxidative stress, Whalley says. “Ageing neurons are very sensitive to oxidative damage.”
Journal reference: Addictive Behaviors (vol 30, p 77