Tobacco addiction is an addiction to products containing tobacco and caused by dependence on the narcotic drug nicotine.

Nicotine dependence occurs when you need nicotine and can’t stop using it. Nicotine is the chemical in tobacco that makes it hard to quit. Nicotine produces pleasing effects in your brain, but these effects are temporary. So you reach for another cigarette.

The more you smoke, the more nicotine you need to feel good. When you try to stop, you experience unpleasant mental and physical changes. These are symptoms of nicotine withdrawal.