For some people it is very hard to stop smoking. In this video experts from the Mayo Clinic explain why. The video illustrates the way in which cigarettes deliver nicotine to the brain causing changes in the brain that lead to addiction. When a person stops smoking they often experience difficult withdrawal symptoms and powerful urges to smoke. The urges and withdrawal symptoms make quitting very hard for many smokers. But hope and help for smokers can be found at the Mayo Clinic website, http://www.mayoclinic.org/ndc-rst/