Smokers have a thinner outer brain layer than non-smokers, scientists have discovered. Past studies have long linked smoking to heightened risk of cancer and lung disease. And research has shown smokers are more likely to endure premature ageing, gum disease, go on to develop Alzheimer’s and heart disease. But if that long list is not reason enough to stub out your last cigarette, a new study has revealed the damaging effect smoking has on the brain. Scientists in Edinburgh and Montreal found the brain cortex is thicker in non-smokers than smokers. The cortex is the outer layer of the brain in which critical cognitive functions such as memory, language and perception take place.