Nicotine and Cocaine Are Similar Types of Addictive Drugs
Addictive drugs like cocaine, heroin, and morphine cause the release of the neurotransmitter dopamine in the brain and the stimulation of nerves. With higher doses of the drug, more dopamine is released. However, higher levels of dopamine activate a feedback mechanism that causes the nervous system to be less sensitive to the neurotransmitter. Drug users become addicted when they then increase the dose in order to get the level of nerve stimulation they were getting with the smaller doses.

In recent research, scientists found that nicotine has the same affect on the brain as cocaine and other addictive drugs. Nicotine also causes the release of dopamine, and this release occurs in the same region of the brain in which other addictive drugs cause the release of dopamine. Having the ability to stimulate dopamine, nicotine is now categorized along with cocaine and other addictive drugs. This finding suggests that some of the ways that are currently used to treat cocaine addiction may also be effective in treating nicotine addiction.

Source: "Similarities Found Between Nicotine and Cocaine" by The Associated Press, New York Times, June 18, 1996