After a decades-long pause on LSD medical research, the results of the first LSD study approved by the U.S. Food and Drug Administration in 40 years have put the drug's potential medical benefits back in the spotlight.

Picking up where the medical community left off in the '60s, scientists recently investigated the effects of LSD-assisted therapy on 12 terminally ill patients approaching death. The findings of this controlled study, published Tuesday in the peer-reviewed Journal of Nervous and Mental Disease, showed that LSD paired with psychotherapy alleviated end-of-life anxiety in patients suffering from terminal illnesses.

Conducted in Switzerland, where scientist Albert Hoffman first synthesized LSD in 1938, the study separated the 12 patients into two groups that underwent two preparatory therapy sessions before being administered LSD. For the trial, patients stopped taking any anti-anxiety or antidepressant medications and avoided alcohol for 24 hours prior to the study. One group was administered 200 micrograms of LSD and the other group 20 micrograms (a barely noticeable dosing). Each individual underwent two dosing sessions separated by a few weeks and were assisted by therapists, who walked them through their experiences with the psychedelic's effects. No prolonged negative effects of the drug were reported.

The low-dosage group reported that their anxiety got worse, while the higher-dosage group said their drug-therapy sessions had profound positive effects on their anxiety -- a clinical indication that psychedelic therapy may have potential as a medical treatment. In follow-up sessions, patients reported their reduced anxiety levels were maintained.

“People are more scared of dying than they are of using drugs. That’s why we were able to start LSD research with people who were anxious about dying, that and the combination of Albert Hoffman and good contacts with the Swiss equivalent of the FDA,” Rick Doblin, founder of the Multidisciplinary Association for Psychedelic Studies, which largely funded the study, told The Huffington Post over the phone.

Neal M. Goldsmith, Ph.D., a New York-based psychotherapist and author of the book Psychedelic Healing, explained the significance of this research to HuffPost. “It has long-term implications for society. In the short term it’s going to help patients, people. So the question really becomes, what’s the benefit of a spiritual epiphany or relief or relaxation? And what’s the effect of that on a dying patient?” he said. "We’re going to be a better society once we learn to reintegrate psychedelics. It both requires changes in society and it creates changes."

While it is unknown from a medical standpoint what exactly happens to the brain under the effects of LSD, Doblin said the psychoactive ingredients interact with the brain’s filtering system and allow for suppressed thoughts and feelings to reveal themselves, making way for confrontation and potentially for healing.

Doblin said LSD-assisted therapy is partly a cathartic and mystical experience, a transcendence of time and space that helps patients fearing death shift their thinking from focusing on the time they don't have left to the time they do have.

“Something is fundamentally changed by successful LSD-assisted psychotherapy," he said. "That’s not to say it works in everybody, but there can be permanent changes in people’s attitudes and in their brains.”

A patient named Peter, who was involved in the study, told The New York Times about his experiences. “I had what you would call a mystical experience, I guess, lasting for some time, and the major part was pure distress at all these memories I had successfully forgotten for decades,” he said. “These painful feelings, regrets, this fear of death. I remember feeling very cold for a long time. I was shivering, even though I was sweating. It was a mental coldness, I think, a memory of neglect.”

That sentiment of the psychedelic’s effects on the psyche is not isolated to this trial. A 2012 study, published in the Journal of Psychopharmacology, showed that LSD had a "significant beneficial effect" on alcohol abuse. In that trial of 500 patients, 59 percent of those who were administered LSD showed reduced levels of alcohol misuse.

LSD was officially made illegal in the U.S. in 1966 as a result of "increased nonmedical use," shutting down all research of its potential medical benefits. Now LSD is classified as a Schedule I substance alongside heroin and marijuana, meaning it is considered to serve no legitimate medical purpose and has a high potential for abuse.

As the FDA begins to loosen its restrictions on researching psychedelics' therapeutic capabilities, studies are emerging from many major university medical research communities. Johns Hopkins University is conducting a study of psilocybin (the psychedelic compound found in certain mushroom species) and its effects on cancer patients to find out if the substance can produce personally and spiritually meaningful experiences. New York University's Psilocybin Cancer Project is also investigating the psychedelic's effect on reducing depression and anxiety in cancer patients. At Harvard Medical School, a study of MDMA sessions with cancer patients suffering from end-of-life anxiety is in the works.

“LSD was the last of the drugs to re-enter the lab, because it’s the quintessential symbol of the '60s. So our ability to do this study and the publication of the article in The New York Times is the culmination of the end of the suppression of psychedelic research,” Doblin told HuffPost.

The Swiss group’s first clinical trial is just a small step toward what some scientists hope will bring psychedelic therapy to the mainstream through a medical route, following the decades-long halt in research. A larger study pool, Doblin said, would prove that LSD has a place in the medical community.