WASHINGTON (AP) — LSD reduced symptoms of anxiety in a midstage study published Thursday, paving the way for additional testing and possible medical approval of a psychedelic drug that has been banned in the U.S. for more than a half century.

The results from drugmaker Mindmed tested several doses of LSD in patients with moderate-to-severe generalized anxiety disorder, with the benefits lasting as long as three months. The company plans to conduct follow-up studies to confirm the results and then apply for Food and Drug Administration approval.

Beginning in the 1950s, researchers published a flurry of papers exploring LSD’s therapeutic uses, though most of them don’t meet modern standards.

“I see this paper as a clear step in the direction of reviving that old research, applying our modern standards and determining what are the real costs and benefits of these compounds,” said Frederick Barrett, who directs Johns Hopkins University’s psychedelic center and was not involved in the research.

Psychedelics are in the midst of a popular and scientific comeback, with conferences, documentaries, books and medical journals exploring their potential for conditions like depression, anxiety and post-traumatic stress disorder.

The FDA has designated psilocybin, MDMA and now LSD as potential “breakthrough” therapies based on early results.

Still, the drugs have not had a glide path to the market.

Last year, the FDA rejected MDMA — also known as ecstasy — as a treatment for PTSD, citing flawed study methods, potential research bias and other issues.