TAKE A PUFF OF TOBACCO, AND A BLAST OF 4,000 CHEMICALS fills your lungs, blood and brain. The smoke delivers a strong hit--about 2 mg in each cigarette--of nicotine, a compound the U.S. Surgeon General in 1988 deemed an addictive drug. But is nicotine alone what hooks people on tobacco? Apparently not. According to a new report, smoking may exert yet another powerfully addictive influence, one that enhances the effect of nicotine in what a leading researcher calls a "diabolical synergism."
In the new research, published in the journal Nature, scientists ran brain scans on smokers and abstainers and found that...