Tobacco Addiction Health Center

Nicotine dependence is an addiction to tobacco products caused by the drug nicotine. Nicotine dependence — also referred to as tobacco dependence — means you can't stop using the substance, even though it's causing you harm. While it's the nicotine in tobacco that causes nicotine dependence, the toxic effects come mainly from other substances in tobacco. Smokers have much higher rates of heart disease, stroke and cancer than do nonsmokers.

Nicotine produces physical and mood-altering effects in your brain that are temporarily pleasing. These effects make you want to use tobacco and lead to dependence. At the same time, stopping tobacco use causes withdrawal symptoms, including irritability and anxiety.