An experiment forty years in the making
For decades, clinical research with LSD was effectively frozen. This was not so much due to the letter of international treaties—which, in theory, restrict the sale and purchase while leaving the door open for science—but rather due to practice: governments rarely granted the necessary permits to test Schedule I substances for therapeutic purposes. The study we review here broke that paralysis. Conducted in Switzerland between 2008 and 2012 and authorized by regulatory committees in 2007, it was the first therapeutic trial with LSD in more than forty years.
There is a detail with symbolic weight: Albert Hofmann, who synthesized the molecule in the 1930s, died on April 29, 2008, just a few days after the anniversary of his discovery. He lived to see what he himself called his “problem child” return to the table of academic medicine.
Why Switzerland
It is no coincidence that the trial took place there. Switzerland has historically maintained a more permissive stance toward psychedelic research. Researchers at the University Hospital of Zurich have spent years studying the neurobiological effects of psilocybin and, later, LSD itself. Between 1988 and 1993, the country allowed a group of clinicians organized under the Swiss Medical Society for Psycholytic Therapy to work with LSD and MDMA in their private practices.
Peter Gasser himself had followed up on those patients treated during that legal window. The idea of reactivating the research took shape in 2006, during a symposium held in Switzerland for Hofmann’s centenary. There, as the story goes, Gasser and Rick Doblin—founder of the U.S.-based organization MAPS—discussed resuming the work interrupted in 1972 and decided to tackle the long bureaucratic process that would make it possible.
How it was designed
Twelve patients diagnosed with life-threatening illnesses—including metastatic cancer—and suffering from very high levels of anxiety participated. Many also struggled with major depression, dysthymia, or generalized anxiety. Those with psychotic disorders, bipolar disorder, or other severe mental health conditions were excluded, a standard and reasonable precaution in this type of research.
The process spanned three months. Each patient received six to eight sessions of talk therapy and two sessions with the substance, lasting eight to ten hours each, conducted by a pair of therapists (one man and one woman) with evocative music and minimal conversation. Eight people formed the active group and four the control group. Measurements of anxiety, quality of life, and psychopathological symptoms were taken before treatment, one week after each session, and at two and twelve months. Those in the control group were later offered the opportunity to undergo two sessions with the active substance.
In addition to quantitative data, the study included something rare: in-depth, recorded, and transcribed interviews analyzed using qualitative discourse analysis techniques. The goal was to understand the experience from the inside, not just measure it on a scale.
What they found
On anxiety scales, the active group showed significant decreases compared to the control group, and these reductions remained stable at the twelve-month follow-up. Scores also dropped for patients who, after going through the control phase, later accessed sessions with the substance.
Of the nine people interviewed, all reported some benefit. Nearly 78% reported a sustained reduction in anxiety and less fear of death; two-thirds reported an improvement in their quality of life. The most frequently cited changes were in their way of being in the world: greater openness, deeper awareness, and more calm and tolerance toward themselves and others. Three participants passed away from their illness after the one-year follow-up.
The narratives were grouped into categories that give an idea of the tone of the experiences: access to repressed emotions and a form of catharsis; the ability to view one’s own situation from another angle; shifts in underlying emotions during the session; and, in the longer term, a reordering of priorities—placing health and family above material concerns. One patient summarized it by saying she no longer cried every night and could now laugh at her own aching body. Another described the difference from talk therapy: verbal therapy works with words; LSD-assisted therapy, he said, works with internal processes.
Not everything was peaceful. Some participants described “exhausting” stretches, the sensation of being trapped for hours in an uncomfortable state from which it was not easy to escape. However, none reported negative sequelae beyond those transient difficulties—intense emotions, temporary loss of the sense of control—inherent to the substance’s effect.
There was also a curious side finding: two patients with severe cyclic migraines noted a remarkable improvement during the following year, in line with what other observations suggest about the effect of LSD on certain types of headaches, particularly cluster headaches.
Critical reading
It is best to read these results with a cool head, and the authors themselves were cautious in doing so. Twelve patients is a very small number: with such a sample, any statistical analysis has an orienting value, not a conclusive one. The enthusiasm with which these studies are sometimes disseminated often runs ahead of what they actually allow us to claim.
There are other nuances. Comparison with the control group is delicate when the subjective experience of LSD makes it almost impossible to maintain a “blind”: patient and therapist usually intuit who has received what, which opens the door to expectations that influence the result. Intensive therapeutic support—eight to ten hours with two professionals—is also a massive variable on its own, difficult to separate from the effect of the molecule.
The work is part of a broader line of research that has also explored psilocybin for end-of-life distress. In those studies, improvements appeared more sporadically; here, they were sustained at twelve months, which is striking, although the difference in designs and doses prevents a clean comparison. The reasonable conclusion is not that “LSD cures terminal anxiety,” but that there are signals solid enough to justify larger, better-controlled trials. In fact, research has continued to advance since then.
Finally, a note of context. What is described here occurred within an authorized clinical trial, with psychiatric screening, controlled doses in a hospital setting, and professional support throughout the session. None of this resembles autonomous use: in people with severe psychiatric pathology or in conditions of medical fragility, these substances can trigger intense crises. The value of this study lies precisely in the framework surrounding it, not just in the molecule.
