Most Americans Think Weed Is Good for You—But Scientists Aren't so Sure

The vast majority of Americans believe weed has at least some health benefits despite a lack of evidence, scientists have warned.

Of 9,000 U.S. adults that responded to an online survey, 81 percent thought the drug had one or more health benefits, researchers found in a study published by the journal Annals of Internal Medicine.

Some 66 percent of respondents thought pot could help with pain, and 48 percent believed it might benefit those with diseases like epilepsy and multiple sclerosis. Almost half of those surveyed thought the drug could help treat problems like depression, anxiety and stress.

But the study authors caution many of these benefits are not supported by scientific evidence. The U.S. Drug Enforcement Administration (DEA) categorizes marijuana—alongside heroin and MDMA—as a Schedule I substance under the Controlled Substances Act. Intended to limit access to the public, it also limits the ability of researchers to investigate the drug, leading to a dearth of solid scientific evidence.

Although a number of states allow the use of marijuana for medicinal purposes—and some have decriminalized its recreation use—it has "no federally approved medical use for treatment in the U.S.," the DEA reports.

"[People] believe things that we have no data for," study author Salomeh Keyhani, a general internist and health services researcher at the University of California San Francisco medical school, told The Guardian. "We need better data...We need any data."

Aggressive marketing and the drug's commercialization, Keyhani said, are likely a factor in the public's positive perception of pot.

In spite of a lack of good study data, some sellers still recommend the drug to treat conditions such as morning sickness. A recent study published in the journal Obstetrics and Gynecology found nearly 70 percent of Colorado dispensaries recommend marijuana products for pregnancy-related nausea, even though the drug may present risks to fetuses.

Although most survey respondents thought marijuana has its benefits, they certainly didn't think it came without dangers. The vast majority (91 percent) believe weed has risks, including legal problems, addiction and memory problems.

The authors caution their results may be limited by the wording of questions in the survey, but they still conclude Americans have more faith in the benefits of marijuana than scientific evidence can support.

Outside of the U.S., Canada is set to legalize cannabis for recreational use on October 17. Weed fans are preparing for the occasion by brewing marijuana beer, but not everyone is happy. Russia has called the decision a "breach" of Canada's "international legal obligations."