There is no scientific evidence for the theory that marijuana is a "gateway" drug. The cannabis-using cultures in Asia, the Middle East, Africa and Latin America show no propensity for other drugs. The gateway theory took hold in the sixties, when marijuana became the leading new recreational drug. It was refuted by events in the eighties, when cocaine abuse exploded at the same time marijuana use declined. As we have seen, there is evidence that cannabis may substitute for alcohol and other "hard" drugs. A recent survey by Dr. Patricia Morgan of the University of California at Berekeley found that a significant number of pot smokers and dealers switched to methamphetamine "ice" when Hawaii's marijuana eradication program created a shortage of pot.(15) Dr. Morgan noted a similar phenomenon in California, where cocaine use soared in the wake of the CAMP helicopter eradication campaign.The one way in which marijuana does lead to other drugs is through its illegality: persons who deal in marijuana are likely to deal in other illicit drugs as well.