Article posted Thursday, June 11, 2015 2:49pm

The outer surface (the cortex) of the brain plays a major role in a person’s thinking ability. Studies have also linked the thickness of the cortex with Alzheimer’s disease, schizophrenia, and loss of balance. Now scientists discovered that long-term smoking results in shrinking of the brain, mainly because the cortex of smokers thins out over time. Loss of cortical neurons affects memory, language, perception, and intelligence in a dose-dependent way – in other words, each year of smoking diminishes the thickness of the cortex, and the more one smokes, the more rapid are these changes. Researchers at McGill University analyzed brain scans of more than 500 smokers, nonsmokers and former smokers with an average age of 73 years. After smokers quit, sometimes there is a slow increase in the thickness of the cortex although the loss of thinking ability may persist for decades. (Karama et al, 2015, Molecular Psychiatry, pp. 1-8; The Week, Feb. 27, 2015)