>> i'm astonished to hear people suggest we can solve our heroin, crisis, have you heard this, by having more marijuana. how stupid is that? >> this bills become so addictive. the dea said a huge percentage of heroin addiction starts with prescription. we think it's starting wit murn and other drugs. >> marijuana as a gateway drug to more dangerous, more lethal narcotics. it's a notion that has steered policy and public opinion for decades. >> leading medical researchers are coming to the conclusion that marijuana, pot, grass, whatever you want to call it, is probably the most dangerous drug in the united states. >> but what if that long-held notion isn't true? >> there's really no evidence that cannabis is did gateway to hard drugs. ten years of clinical experience i have never seen it. >> gateway sure. greatway to feeling better and