By Philip J. Hilts, New York Times, Aug. 2, 1994 Is Nicotine Addictive? It Depends on Whose Criteria You Use. Experts say the definition of addiction is evolving. WASHINGTON - When heavily dependent users of cocaine are asked to compare the urge to take cocaine with the urge to smoke cigarettes, about 45 percent say the urge to smoke is as strong or stronger than that for cocaine. Among heroin' ad