A new study suggests Ecstasy may help treat post-traumatic stress disorder (PTSD), according to The New York Times.

Researchers in South Carolina found Ecstasy combined with psychotherapy helped 15 of 21 patients recover from severe post-traumatic stress. Most of the patients in the study were rape victims.

It is unknown whether the treatment is effective in war-related PTSD, the article notes. The researchers are beginning to test the drug in veterans. “We’ve had more than 250 vets call us,” researcher Michael Mithoefer told the newspaper. “There’s a long waiting list, we wish we could enroll them all.” He and his wife, Ann, will work with other scientists to test the treatment in no more than 24 veterans, in order to comply with Food and Drug Administration rules for testing an experimental drug.

Ecstasy, also known as MDMA, is not approved for any medical uses. Previous studies of the drug suggest it induces release of the hormone oxytocin, which increases sensations of trust and affection. The drug also appears to reduce activity in the brain that increases during fearful, threatening situations.

The study appears in the Journal of Psychopharmacology.