The “mindfulness” industry has been growing rapidly in recent years, coming alongside the ancient tradition of meditation as a means of finding serenity and improving mental health.

But has the hype gotten ahead of the science? Experts think that’s possible.

“We are sometimes overselling the benefits of mindfulness to pretty much any person who has any condition, without much caution, nuance, or condition-specific modifications, instructor training criteria, and basic science around mechanism of action,” says Willoughby Britton, co-author of a new paper on the topic and an assistant professor of psychiatry and behavior at the Warren Alpert Medical School of Brown University. “The possibility of unsafe or adverse effects has been largely ignored. This situation is not unique to mindfulness, but because of mindfulness’s widespread use in mental health, schools, and apps, it is not ideal from a public health perspective.”

One major problem? Simply defining “mindfulness,” which is described in many different ways throughout the media and in scientific literature.