What about other drugs? Do the same genetic relationships demonstrated in the alcohol adoption studies prove true for other drugs? Was it conceivable that heroin addiction or cigarette smoking could be traits (disorders, really) that men and women inherited? “There have been a number of animal studies showing genetic differences in sensitivity to nicotine,” said Dr. Neal Benowitz of the Clinical Pharmacology Unit at San Francisco General Hospital, one of the nation’s premier nicotine research centers. And Professor Ovide Pomerleau, the Director of Behavioral Medicine at the University of Michigan Medical School, who collaborated with Cloninger’s group on genetic studies of nicotine and alcohol, told me: “Some people are drawn to smoking, and some people are not. Everybody pretty much goes through the same kind of peer pressures, the same kind of socialization pressures, and then you have some people who emerge as smokers, and some people who don’t. Some people who start smoking give it up easily, and there are others who can’t. Well, why? My answer is that I think there are innate differences in susceptibility.”