Cannabis plants that contain high amounts of cannabidiol (CBD) are tended at a cultivation facility in Wray in May 2014. (Joe Amon, Denver Post file)

Op-ed: Congress has ignored need for marijuana research for too long

Members of Congress are often eager to admit they’re not scientists. The trouble is, they also don’t like listening to scientists and have tried to keep them from shaping federal policy on issues from national defense to environmental protection to gun violence. Now, America’s ignorance-is-bliss Congress has come to fear what scientists might have to say about marijuana.

Earlier this month, the House Rules Committee rejected an amendment to a biomedical-research bill that would have directed the National Institutes of Health to investigate the benefits and risks of using marijuana for medical purposes — research that federal law currently hampers. The sponsors of the amendment hold conflicting views about the value of medical marijuana. Each side believes that more research will strengthen its case, but they have yet to convince House Republican leaders.

Gathering data is indeed an excellent way to clarify and advance debate. Nearly half of all states have legalized medical marijuana, but the political discussions involved in this process have been dominated by stories of heartbreaking suffering and frightening drug abuse. Ideology has played a role, too, with liberals and libertarians lining up against cultural conservatives.

Largely missing from the debate has been the most essential element: scientific evidence suggesting that marijuana does anything to alleviate physical suffering.

A study released in June found weak evidence to support using marijuana to treat many conditions for which states have approved it, including nausea from chemotherapy, sleep disorders and Tourette’s Syndrome. It did better in treating chronic pain and spasticity arising from multiple sclerosis.

Yet states have adopted laws that allow the drug to be used to treat everything from anxiety to writer’s cramp. One medical practice in California, which is devoted entirely to authorizing marijuana use, lists more than 250 qualifying conditions. Other states have adopted more stringent rules, but even these laws go beyond what the scientific evidence supports.

Pot is not harmless, after all. It’s associated with a wide range of dangers. Too little is known about how it affects brain development (particularly among teenagers), mental health and lung disease. For people who are already seriously ill, it could end up doing more harm than good — especially today’s more potent strains and highly intoxicating edible products. To treat medical marijuana as a stalking horse for full legalization, as many of its advocates do, is plainly irresponsible.

Protecting public health and safety requires arming both patients and lawmakers with better information. This requires that opponents of medical marijuana in Congress put more faith in science.

To contact the senior editor responsible for Bloomberg View’s editorials: David Shipley at