Quote Originally Posted by BlueCat
There is no evidence that smoking marijuana leads to the use of harder drugs. In the first place, it is chemically illogical that the consumption of any drug could give someone the craving for another drug they have never had.
This is somewhat inaccurate and misleading. While is true that the majority of people who start off using marijuana do not go on to become users of harder drugs like heroin or cocaine, the vast majority of people who are regular users of harder drugs did start with marijuana. Thus, there is at least some evidence that marijuana use can lead to the use of harder drugs, but it is by no means a given that this will occur. It's not that the use of one drug magically creates a chemical craving for another, it's that once the natural initial reluctance to try drugs has been broken with the introduction of the rather pleasant and benign experience of marijuana, it becomes easier for the individual to experiment further with other drugs.