Attitudes towards marijuana are changing fast. Once widely seen as a nasty gateway drug that turns your brain into gray slush, more and more Americans are beginning to associate marijuana with healthy living and medicinal properties.

Much of the drug’s fanbase welcomes this loosening of attitudes, however, a new study claims that public perceptions of marijuana are often unfounded, unscientific, and misled. Granted, there is a bunch of evidence out there that hints at how marijuana could be used in certain medical treatments, however, it’s important not to overstate the drug’s health benefits or downplay its risks before the scientific research gets there.

“They believe things that we have no data for,” lead author Dr Salomeh Keyhani of the University of California, San Francisco, told The Guardian.

The research, published this week in the Annals of Internal Medicine, asked over 16,000 nationally representative US adults about their views on the benefits and risks of marijuana via an online survey, of which at least 14 percent said they had smoked or ingested marijuana in the past year.

Over 80 percent of people said they believe marijuana holds at least one beneficial property – something that the researchers do not argue with. As the respondents correctly pointed out, marijuana has shown promise when it comes to treating certain conditions such as chronic pain, reducing nausea during chemotherapy, and increasing the appetite of people with HIV/AIDS.

However, nearly a third of people (29.2 percent) argued that smoking marijuana actively prevents health problems – a statement that does not have conclusive clinical evidence to back it up.

“The American public has a much more favorable point of view than is warranted by the evidence,” Dr Keyhani told Reuters.

“Perhaps most concerning is that they think that it prevents health problems.”

Equally, many people appear to understate the risks involved in using marijuana. Nearly 1 in 10 reported that marijuana use has no risks at all. Out of the 91 percent that said it has at least one risk, the most commonly identified was legal problems (51.8 percent), followed by dependency and addiction (50 percent), and fuzzy memory (42 percent).

About 18 percent thought secondhand weed smoke is somewhat or completely safe for adults, plus a staggering 7.6 percent said that it is somewhat or completely safe for kids. Furthermore, 27.6 percent believe driving while stoned is considerably safer than driving while drunk. 

The physicians and public experts who led the research argue that this optimistic view is not in line with the current scientific consensus on the risks and benefits of marijuana. Part of the problem, so say the researchers, is the massive influence of advertising and pop culture. Equally, a lack of real legitimate research means conclusions are often reached from personal or anecdotal evidence, not actual science.