Why medical experts are hesitant about CBD

It's important to know that the research in this area is in its infancy, partly because we haven't really understood much about CBD oil until relatively recently," said Marcel Bonn-Miller, an adjunct assistant professor at the University of Pennsylvania Perelman School of Medicine. He pointed out that the classification of marijuana as a Schedule 1 drug by the DEA makes it difficult to get material to use in laboratory studies. Schedule 1 drugs have a high potential for abuse, according to the DEA, and are illegal under federal law.

Because of this classification, it's not easy for researchers to get their hands on the drug. "That's not to say you can't do it, but there are hoops you need to jump through that can be a pain, which may deter researchers from going into this space," Bonn-Miller said. "Relatively speaking, it's a small group of people in the U.S. that do research on cannabinoids in humans."

However, Bonn-Miller told Live Science that he thinks cannabis research is on the upswing. "If we flash forward five years I think you'll see more studies," he said. Those studies could reveal more conditions that CBD may be helpful for and may also reveal that some of the reasons why people say they use CBD oil are not supported by the science but are instead a placebo effect. "And that's why we need to do the studies," he said.  

The side effects and risks involved with consuming marijuana-based products aren't clear, either, Bonn-Miller said. It's important to "determine cannabinoids that are useful therapeutically while understanding and using cannabinoids that are associated with less risk," he said. At least with CBD, he said, it doesn't appear to have the potential for addiction. That's different from THC, which has been associated with addiction, he said, and negative side effects, including acute anxiety.