Where is evidence of hazards of pot?

In his Feb. column on medical and recreational marijuana, Doug Turner makes the statement: “Marijuana is a gateway for hard drugs, and plenty hazardous by itself.” I have seen this statement many times, especially in recent months, but I have never seen any reference to a detailed study or studies that bear this out. I do see, from time to time, statements like this from a police officer to that effect, but remember that statement only covers some drug users.

There is a large marijuana industry out there, and it must cater to a large number of users, and probably very few are caught. So there are no large-scale studies of marijuana users and whether they progress in large numbers to hard drugs. If there are such studies, no one seems to use them to try to justify stopping marijuana use. For the record, I have never used pot, and to the best of my recollection, I am not acquainted with pot users.

Paul R. Libby