I don’t use marijuana, and this link is to NORML, but this page is very interesting.
Preclinical data recently published in the Journal of Clinical Investigation demonstrating that cannabinoids may spur brain cell growth has reignited the international debate regarding the impact of marijuana on the brain. However, unlike previous pseudo-scientific campaigns that attempted to link pot smoking with a litany of cognitive abnormalities, modern research suggests what many cannabis enthusiasts have speculated all along: ganja is good for you.
I don’t know if ganja is good for you, but I support the legalization of marijuana as a matter of good public policy.