I stumbled onto this website that contains a large listing of free documentary's that anyone can watch for free. Its legal and has a large listing of documentary's on drugs, some which I can vouch are very good documentary's. I suggest you check if out if you want to get some good information on the current views of drugs and their uses. There are also many other documentary's on other subjects as well.
Check it out: http://topdocumentaryfilms.com/watch-online/