All photos by the author unless otherwise noted

It's not hard to get acid in 2015. A lot of people sell it and a lot of people do it. But there's only one man in the world who's legally authorized to offer up a healthy dose of lysergic acid diethylamide.

Meet Dr. Peter Gasser, the Swiss psychiatrist who's spent nearly a decade taking a deep dive into psychedelic research, picking up where Albert Hofmann, known as the first person to synthesize and ingest LSD, left off in 1966, when LSD was made illegal in and research on the substance nearly went extinct. Hofmann personally met with Gasser several times to give the Swiss doctor his blessing about Gasser's foray into experimental therapy aided by psychoactive drugs.

Gasser has been interested in psychedelics from a medicinal standpoint ever since he took LSD nearly 25 years ago. In 1988, the Swiss Federal Office for Public Health granted him special permission to certain psychiatrists to begin research with the drug, despite the global ban. He was one of five therapists in Switzerland who was legally allowed to implement MDMA and LSD into his research and tried the psychoactive treatment himself—at least until Switzerland banned LSD again in 1993.

Dr. Gasser wasn't done integrating acid into his therapy research, though. "The existence of these substances is a reality, so it seems to me more helpful to investigate their potential benefits and risks than to prevent research," he wrote in a newsletter for the Multidisciplinary Association for Psychedelic Studies (MAPS) in 1994. "Continued ignorance will not prevent prohibited substances from being used destructively in the underground.

In 2007, the Swiss Ministry of Health approved a pilot study of his that looked at the effects of acid administered to patients suffering from cancer and other terminal diseases, which was sponsored by MAPS. Each patient underwent two drug-assisted therapy sessions with a break in between. After seven years of research, the study was published last year under the name "LSD-assisted psychotherapy for anxiety associated with a life-threatening disease: A qualitative study of acute and sustained subjective effects." This was the first controlled trial of the drug in the 21st century.

"Several [subjects] died within a year after the trial—but not before having a mental adventure that appeared to have eased the existential gloom of their last days," wrote the New York Times.

Gasser was a featured speaker at last year's Horizons: Perspectives in Psychedelic Research conference in New York City, and after presenting the data from his pilot study he announced that he'd successfully applied to the Swiss government for "compassionate use" authorization to include LSD in his therapy practice. He continues to administer the drug to patients today, in both individual and group settings. He currently has seven approved patients for LSD treatment, three of whom will undergo a ten-hour session this month.

The doctor's office is on a quiet street in Solothurn, a village in the northwest of Switzerland. The building resembles any other therapist's office, with a simple sign at the entrance and a white waiting room adorned with bookshelves, paintings, and flowers. The only thing remotely psychedelic is Gasser's therapy room, lined with comfortable couches and floor cushions, a statue of Buddha, and a nice stereo system that no doubt is integrated into his guided trips.

I recently sat down with the doctor there to discuss his life's work.

VICE: You're the only person in the world with this permission to administer LSD for therapeutic treatment, right?

Peter Gasser: Yes, correct. Interestingly, my friend Dr. Peter Oehen lives nearby and he does the same thing with MDMA. He got permission for MDMA treatment with compassionate use. And Dr. Torsten Passie [a psychiatrist in Germany] is trying to get permission to use Bromo-LSD for treating cluster headache, but he has not been able to get permission from the German authorities.

What do you think LSD adds to your therapy that you weren't able to bring to your practice before?

I am convinced that LSD can bring additional benefit for some patients. I experienced that myself when I had the opportunity to do it when I was younger. I also saw this in the study I conducted and through the patients I've already treated with LSD. I think it has another quality to it than just treating patients through talk therapy, gestalt, behavioral therapy, or whatever. Which does not mean that I would say it's the only [treatment], the real one, or the best one. Rather, I'd think that it should have its place among other methods. But for some people, I think it's really helpful to go into an altered state of mind, to have maybe spiritual experiences, peak experiences, which is something you cannot achieve with normal therapy.

So who gets it? Who exactly are the patients?

In the LSD study we just worked with cancer patients. Our concept was if someone gets a life-threatening disease, he's really confronted with existential issues, which also may cause anxiety. To have this deep encounter with oneself—which is what an LSD experience can be—can help someone deal with these questions about life. There's a stronger possibility of them being relaxed and accepting, which can make the anxiety lower when talking about death. And now I'm trying to now explore LSD's potential in patients with other issues.

I think of course this is a special situation when someone has cancer but there are other situations in life where people are also confronted with deep, important questions, and there I think LSD can be helpful. The difficult question is asking if it should only be for patients, or also for healthy people. Of course a lot of healthy people take it every weekend outside of medicine and therapy and they have good experiences, meaningful experiences. But I have to ask myself, what medical conditions can LSD help with, and what would it not be helpful with?

The good thing with the compassionate use is I am not restricted to cancer patients; I can apply to treat patients with any kind of problems if I have a good theory about what LSD would help with and why exactly LSD would work. If the Swiss government agrees, I'm granted permission to use it.

Watch our doc on Todd Skinner's subterranean LSD palace:

Did you already have a professional relationship with the patients you embarked on this treatment with? Or did compassionate use inspire you to start finding and treating new patients who you thought could benefit from the experimental therapy?

Both, actually. The very first permission I got was for a patient who has been in treatment with me for a very long time. She experienced terrible, severe sexual abuse in her childhood and now suffers from dissociation. And my idea was that LSD could help her because LSD is also, in a way, dissociative—but when you do it in a safe environment, there is no threat of sexual abuse. The substance could help her to have more control over her dissociation. I discussed this theory with the Swiss government, and they followed what I was saying and gave me permission. I would say it works and she really has benefitted from it. She's done two treatments now with LSD and is pretty happy with that. There are others who come to me that say, "Yes I've been through several types of treatment, and I think LSD could help me make the next step forward."

Is there flexibility in how you administer LSD to your patients?

Yes, of course, because compassionate use is treatment. I'm really going to treat the people with what they need. One person can have one LSD session and another can have eight. It's about what's appropriate for them. With research trials, you'd have to give every patient the same amount, but this is different.

How do you decide doses and frequency of use?

I'm allowed to give up to 200 micrograms at one therapy session—that's the limit I applied for—because it's the same dosage we gave in the study. But now when people take it the first time, I only administer 100 micrograms because I think it's really enough and ultimately better. When the dosage is too high, it's really too much and the patient may be afraid. Or it can be too strong so they're fighting and not relaxing. It really depends on the situation and what's appropriate for the patient from a medical standpoint. I can apply to give higher dosages, but I have to give a reason why. Same thing for the frequency of treatment.

After seeing you for the treatment, do any of the patients try using hallucinogens on their own later?

With the study, people said the drug itself wasn't the most interesting aspect to them, but instead it's the drug, it's the music, and the guidance—the whole treatment. They don't only get the drug, and I think that makes a big difference. I must say that almost everyone I've treated is in the second half of his or her life. If they wanted to do drugs they could've done it before. I mean you can get it easily any weekend. Go to a trance party and it's no problem.

"When you take LSD, it won't make everything good. You can have hard times and maybe then you need a therapist or a guide who can help you integrate or embrace such difficult experiences."

Can you tell me about another patient you're treating? What brought them to treatment and why did you decide that the LSD therapy would benefit them?

There was an interesting person, a young man, who's studying for his PhD in philosophy and suffers from a severe anxiety disorder. He experiences debilitating stress when he has to participate in groups or speak during a seminar. And he did a long treatment already including medical treatment, psychological treatment, and Jungian psychoanalysis. He likes his therapist, but he says it only helps him to a certain degree because he can't really tap into his social anxiety in such a controlled setting.

He came to me and I said he should try taking LSD in the small group therapy sessions I've been organizing. And it wasn't easy to convince the government that group therapy was as beneficial as individual therapy, but recently I was able to get approval for that. I think he expected to do individual LSD therapy and this scared him at first. There were only three patients and me in the room. But it was a test and a goal for him to get through it, and he came out of it saying he had a fantastic experience. He said it was the first time in his life that he felt unthreatened by people in a group setting, which felt like a breakthrough [to me]. Now he's going to try and integrate this experience with his life and work. Interestingly, he said he doesn't have the urge to repeat a session like this for a while. He wants to first work on the integration part and then try it again in the spring.

Have you ever had a bad experience with a patient?

I had one older woman in a group therapy session who was about 74. She's suffered from migraines since she was a young woman, meaning over 50 years. She contacted me and she asked if my therapy could help treat her migraines. There are anecdotal reports that LSD can help with migraine, so I asked the government for permission to treat her and they said yes. We tried it and she had a hard experience. She didn't have enough confidence in the situation. Maybe it was too early for her, I don't know. She was really upset, and she felt alienated during the experience, even with myself. I really had to have an intensive talk with her to bring her down from her paranoia.

Eventually, she calmed down and the rest of the day was fine, though she said it didn't help her with the migraines. But she then developed a very existential perspective on what she experienced, and I think she got why she felt so alienated. It had to do with realizing she was getting older and life slowly coming to an end. The isolation or loneliness you may experience at the end of the life became clear, if that makes sense. It was not an easy experience for her. When you take LSD, it won't make everything good. You can have hard times and maybe then you need a therapist or a guide who can help you integrate or embrace such difficult experiences.

An approval letter from the Swiss Ministry of Health granting permission for one patient to receive LSD sessions for up to one year—the closest thing Dr. Gasser has to a prescription.

Why haven't other doctors or therapists tried to do this? Why you? What made you special?

What made me special? I think I've had an interest in these substances for a long time. But also it was luck that I got the permission to conduct my original LSD study, which made me a well-known researcher. If the ethical committee had said no, then that could have been it. But times have changed, and I think now it's easier to get permission and get in all these things. I think people don't try this as much because of the money. You don't get paid and it takes a ton of time. But I get a lot of gratification, and people come to me and want to know what I do. It's an opening to the world for me.