Brain Chemical Makes Cigarettes Addicting

Nicotine has long been known as the source of addiction from cigarettes.  However, it is dopamine that seems to be the true culprit of addiction.  Smokers experience increased dopamine levels because the brain enzyme that breaks down dopamine is 40% less active as compared to a typical person.  On another note, increased dopamine also is correlated with a lower risk to develop Parkinson’s disease.

http://www.nytimes.com/1996/02/22/us/brain-chemical-said-to-play-role-in-cigarette-addiction.html