Marijuana has been under a hysterical attack by the US gov't for decades now. Ask yourself, how many people high on pot have actually robbed a liquor store? None. How many people have died from an overdose of pot? None.
The US NCI now admits marijuana kills cancer cells. A direct link to an image of the site for backup.
The US makes it hard to even study the effects of pot, Europe has done more on this than the US. Don't expect the US to move forward with this. More studies need to be done about how it can be administered for each problem it solves.
More studies about pot from PubMed. Some may just be abstracts. On each abstract page look in the upper right of the page for "Full Text Links" and "View Full Text". Some abstracts have free full text on another website. Screenshot here of where "Full Text Links" is.
Free full studies about marijuana from PLOS.org.