Research like the current research into MDMA therapy has blocked support from various groups and lawmakers in both parties for the treatment of post-traumatic stress disorder, a condition that affects millions of Americans, particularly military veterans who are at enormous risk of suicide . No new treatments for PTSD have been approved for more than 20 years.

“What’s happening is really a paradigm shift for psychiatry,” said David Olson, director of the Institute for Psychedelia and Neurotherapy at UC Davis. “MDMA represents an important step for the industry because there is a real lack of effective treatments and people need help now.”

Amy Emerson, chief executive officer of Lykos Therapeutics, said the company stood by the data and design of its studies, which were developed in consultation with FDA staff members.

“These are not easy study projects; they are very complicated,” she said.

“Functional unmasking,” in which study participants can determine whether they were given a placebo, often influences research on psychoactive drugs because patients are acutely aware of the effects, he said.

A denial of the application would shake up the nascent field of psychedelic medicine, which has attracted millions of dollars in private investment. Much of this support is based on the approval of MDMA therapy, which the FDA granted breakthrough therapy designation, or accelerated review, in 2017.