Smoking is harmful in almost every way. Cancer, strokes and other cardiovascular diseases are only a small part of the serious consequences of smoking. Nicotine can make people addicted to smoking, but new Danish research shows that smoking initially increases brain activity. However, brain tissue adapts quickly and this effect disappears. On the other hand, brain scans showed that immediately after stopping smoking, oxygen uptake and blood flow to the brain decreased by more than 17 percent. Brain scans show that regular smokers who quit smoking develop an almost dementia-like condition in the early morning hours. This can be quite an unpleasant experience, and may be one of the reasons why quitting smoking is so difficult. Professor Albert Gjedde, a neuroscience researcher in the Department of Neuropharmacology at the University of Copenhagen, said that smokers are unable to quit, perhaps not because of the pleasant effects obtained – the ship has sailed – but because the withdrawal symptoms are unbearable. Together with Associate Professor Manouchehr SeyediVafaee and other scientists from the same department, Dr. Albert Gjedde published the new findings in the Journal of Cerebral Blood Flow and Metabolism. The researchers compared the nicotine in tobacco smoke with other pharmacologically active substances. After a period of time, the therapeutic effects no longer appeared for many drug users – for example, antidepressants. But Albert Gjedde says the consequences of stopping treatment can be overwhelming if the withdrawal symptoms are very unpleasant. Habitual smokers seem to need to smoke only to continue the normal activity of their brains. Over time, they may become less dependent on smoking, but the researchers don’t know how long it takes for the brains of former smokers to return to normal energy expenditure and blood flow before they already have: We speculate that it takes weeks or months, but we can’t say for sure. Albert Gjedde says the new findings suggest that gradual cessation may be a good idea — -Just to avoid the worst withdrawal symptoms, i.e., the difficulty of holding the very wise decision to quit smoking. He stressed that there are still many blind spots in the research on the brain of smokers.