I've written about this subject a lot and rather then repost the links and references again i'll just give a quick summing up. The term addictive is wildly and loosely applied to anything enjoyable that carries health risks. In a clinical sense chemical dependencies entail all sorts of deablitating withdrawl effects that simply are not present in tobacco. Unlike narcotics tobacco use is typically ended without prescription drugs, medical internment or professional help of any kind. The simple reality is that over 90% of former smokers quit without any of the formentioned which means that it is uniquely abandonable and unique among "additictive" substances. Like everything else in the mass media reporting on tobacco sensational, poorly researched, biased and wildly over stated. If you are interested in tobacco I suggest that you start by reading the excellent www.forces.org
site and perhaps some introductory texts on emperical method which I could remend if you are so interested.