Cannabis leads to hard drugs. However when the same dealer sells them, which they are doing with the present system there is a connection. The Dutch with their coffee shops have removed that link and now the heroin user in Holland has an average age of 44, compared to the UKs average age of 19. This indicates that the prohibition laws are the real gateway. Usually though, the first drug tried by a junkie is alcohol more often than it is cannabis.
Cannabis is a lot stronger than it was.
Apparently this myth came about because of bad storage practice of old samples. Cannabis is addictive. Cannabis causes road accidents. Not so, according to the most recent report from the TRRL, which says cannabis users are so cautious that a tired driver is more dangerous. Similar reports have come from Canada and Australia.