Marijuana research in the United States is dominated by a lone, big-muscled monopolist: the federal government. An April report by Americans for Safe Access (ASA), a medical marijuana advocacy group, explains why that's bad for both science and sick Americans.
Currently only the National Institute on Drug Abuse (NIDA) can legally supply researchers with marijuana. NIDA, which guards its gatekeeper status jealously, is oriented toward the idea that pot is harmful, not useful. Even when researchers have received Food and Drug Administration approval for their studies, NIDA frequently refuses to sell them the pot they need to carry out their research, essentially exercising a veto on the FDA's decisions.
The FDA has to follow statutory time limits in considering applications, but NIDA can stretch out the process endlessly. This, the ASA report notes, makes it "financially prohibitive for sponsors to invest the millions of dollars needed to conduct research." With NIDA bogarting America's only federally sanctioned weed, the number of privately funded medical cannabis studies currently taking place in America right now is exactly zero. Of the 14 studies investigating marijuana in any way, 13 are NIDA projects looking into drug abuse.
In 2007 an administrative law judge at the Drug Enforcement Administration recommended ending the monopoly, suggesting that the DEA grant licenses to private producers of research cannabis. Although 45 members of Congress have written to the DEA in support of this idea, nothing has changed. The agency justifies the monopoly on the grounds that "diversion" of the marijuana for non-scientific uses would be more likely if multiple sources provided pot for science.