> Tobacco may well be as addictive as heroin, crack, alcohol, and Cherry Garcia combined into one giant crazy sundae. But as laboratory scientists know, getting

> Tobacco may well be as addictive as heroin, crack, alcohol, and Cherry Garcia combined into one giant crazy sundae. But as laboratory scientists know, getting mice or other animals hooked on nicotine all by its lonesome is dauntingly difficult. As a 2007 paper in the journal Neuropharmacology put it, “Tobacco use has one of the highest rates of addiction of any abused drug. Paradoxically, in animal models, nicotine appears to be a weak reinforcer.” > That same study, like many others, found that other ingredients in tobacco smoke are necessary to amp up nicotine’s addictiveness. Those other chemical ingredients things like acetaldehyde, anabasine, nornicotine, anatabine, cotinine, and myosmine—help to keep people hooked on tobacco. On its own, nicotine isn’t enough. https://www.scientificamerican.com/article/will-a-nicotine-patch-make-you-smarter-excerpt/ https://www.scientificamerican.com/article/will-a-nicotine-p... There are other sources and studies I'm too lazy to look up, but AFAIU nicotine is a powerful cognitive enhancer that makes activities easier to perform and more rewarding (including, perhaps, the metabolization of other substances), and it's this experience boost that may be what addicts people. In any event, it's now understood--relatively uncontroversially--that this is why many people with certain cognitive deficits (ADHD, schizophrenia, depression, etc) self-medicate with nicotine, though it works to elevate cognitive performance even for people without deficits.