[GFischer]

Check gwern's site :)

http://www.gwern.net/

He has experimented with lots of drugs, up to and including LSD.

By the way, a close relative does smoke pot (it's legal in my country, Uruguay) and we believe it has brought to the front some (probably preexisting) mental problems which could be described as "going crazy".

I do support legalization, but it's not entirely innocuous (it is my belief it's milder than alcohol, but then again, alcohol does bring some extreme reactions and kills a lot of people)