Actually, while I am not in any way a fan of "drug war" propaganda, there is some truth to that.  Nicotine, although not associated with the immediate physiologic withdrawal that heroin causes, I think is otherwise, at least from a brain physiology point of view, as, or more addictive than heroin.  The opioid receptors ARE turned on with tobacco as with heroin, and the limbic areas where much of the "addiction pathways" are located are near a/o overlap with each other. Also, and although this may be anecdotal, I have never seen a heroin addict (and I treat/meet quite a few in my line of work), who is also a smoker, quit cigarettes, even when they have long gotten over their narcotic addiction.   Same with other polysubstance addictions...if the person is also hooked to cigarettes, the cigarettes are far more difficult to quit than the alcohol, coke, pot etc..So in that instance, I agree with the drug war dogma.  There is a huge literature that shows WHY,biochemically, addictions travel together.  There are a few brain regions which are, basically "joy buzzers", and once you get the buzz, you keep on pushing the knob/button to get mo' mo' mo'... not everybody, obviously, but some of us are prone, and some of us are not.  Do you want to enjoy a drink..or do you "need" a drink?  The distinction is often not black and white but various shades of grey. 

Gene