There is a European thread in the history of psychedelic research that does not often make it into the mainstream narrative. It runs from a Swiss chemistry laboratory in 1943 through the first LSD clinics in England and Germany in the 1950s, through the smart shops of Amsterdam in the 1990s, through research laboratories in Zurich, Barcelona, and London, and it arrives today at over 285 legal retreat centres operating openly in the Netherlands. Most of this happened quietly, some of it underground, and much of it has never been properly recorded.

I lived in the Netherlands from 1995 to 2012, and I have been visiting regularly before and since. From that position I kept encountering pieces of this story that felt important but largely untold: clinical programmes that went back further than most people realise, a cultural infrastructure that kept the questions alive through the dark years, researchers working in relative isolation who produced findings that would only be widely cited much later. This article is an attempt to pull those threads together.

Basel, 1943

The story begins, as any serious account must, in Switzerland. On the afternoon of April 19, 1943, the Swiss chemist Albert Hofmann rode his bicycle home through the streets of Basel, having accidentally absorbed a small amount of a compound he had synthesised five years earlier and set aside. By the time he arrived home, the world was unmistakably different. Hofmann had discovered LSD, and he knew immediately that what he had found was not a drug in the ordinary sense but something that belonged to a different category of experience altogether.

He spent the rest of his long life, he died in 2008 at the age of 102, working to ensure that the substance he called his problem child was understood rather than feared. He was the first to isolate psilocybin and psilocin from the mushroom samples sent to him by Gordon Wasson. He remained an active and lucid advocate for psychedelic research into his final years. And Switzerland, his country, would play a central role in European psychedelic history not once but several times.

The First Clinics: Britain, Germany, and the Netherlands

Within a decade of Hofmann's discovery, European psychiatrists were running clinical programmes with LSD that would not be matched in ambition or seriousness until sixty years later. Ronald Sandison at Powick Hospital in England opened the first LSD clinic in 1953, after reading an early American paper and concluding that the drug might be capable of shortening psychoanalytic treatment considerably. His results were striking. In a follow-up of 94 patients treated with LSD, 65% had recovered or significantly improved. He coined the term psycholytic at the First European Symposium on Psychotherapy under LSD-25, held in Gottingen in 1960, meaning the loosening of the psyche, a term that emphasised the gradual, therapeutic process rather than the overwhelming peak experience.

The Gottingen symposium was organised by Hanscarl Leuner, who had been developing his own approach to LSD-assisted therapy at the University of Gottingen since the mid-1950s. Colleagues came from Denmark, the Netherlands, England, Norway, Czechoslovakia, and Italy. The European Medical Society for Psycholytic Therapy, founded in 1965 with Leuner as president, grew to include 18 affiliated centres across five European countries. At the height of the movement, by Leuner's own count, more than 120 cases had been carefully treated over eight years, with 64% of severely chronic patients reported as recovered or greatly improved, in an average of 38 sessions totalling 65 hours of therapy.

The Netherlands had its own distinct tradition. Jan Bastiaans, professor of psychiatry at Leiden University, became known for his work with concentration camp survivors, people whose trauma was so deep and so resistant that conventional therapy had reached its limits. With LSD, he found that the locked material became accessible. Cornelius van Rhijn treated almost a thousand alcoholics with LSD in Enschede. G.W. Arendsen Hein ran sessions at the Veluweland foundation in Ederveen. In Czechoslovakia, Stanislav Grof and Milan Hausner ran programmes of their own before the political situation made that impossible.

This was a genuinely European clinical tradition, drawing on psychoanalytic rather than spiritual frameworks, and producing results that any honest assessment of the evidence would have to take seriously.

The Interruption and What Survived

At the end of the 1960s and the early 1970s, the scheduling of psychedelics under American law rippled into European legislation via UN conventions, and the clinical tradition was largely shut down. Largely, but not entirely. Jan Bastiaans retained his licence to work with LSD until his retirement in 1988. He continued seeing patients at the Jelgersma clinic in Oegstgeest for nearly two more decades after the rest of his European colleagues had stopped.

In December 1985, more than twenty doctors met in Bern and founded the Swiss Medical Society for Psycholytic Therapy. After sustained advocacy with the Swiss Federal Health Office, five of the founding members received special permits from the Swiss government to work with MDMA and LSD. This window lasted from 1988 to the end of 1993, a brief but extraordinarily productive period in which 121 patients received psycholytic therapy. The follow-up study found that nine out of ten described themselves as improved, with quality of life better for 84% and self-acceptance increased for 82%. Not a single patient required psychiatric hospitalisation as a result of the treatment.

That same year, 1985, Hanscarl Leuner, together with the experimental psychologist Adolf Dittrich and Albert Hofmann as honorary president, founded the European College for the Study of Consciousness. The College met annually for symposia of its approximately 120 members throughout the late 1980s and early 1990s, keeping alive a network of researchers and therapists who refused to accept that the field was finished. Its first large international congress, held in Gottingen in September 1992, drew 500 people and brought the old guard together with a new generation of researchers.

Amsterdam and the Smart Shop Era

In October 1993, Hans van den Hurk opened Conscious Dreams in central Amsterdam, selling magic mushrooms and other legal psychoactive substances from an art gallery space. A man arrived on a bicycle with fresh Psilocybe cubensis mushrooms and asked if he would be interested in selling them. Van den Hurk checked with his lawyers and discovered a gap in the law: while the chemical compound psilocybin was illegal, mushrooms containing it were not. He began selling them, with usage instructions and harm reduction information at the counter. By 1998 there were approximately forty smart shops in Amsterdam. The Dutch experiment had begun.

I worked briefly in a smart shop during those years, and I can say that what it looked like from the inside was quite different from what it looked like from the outside. Not primarily a drug shop. More a harm reduction project with a commercial format, staffed by people who genuinely cared about the effects of what they were selling, who took the time to ask about medication, mental health history, and intention, and who turned people away when the situation was unclear. Not every shop was the same, of course. The earliest ones, in particular, were run by people with genuine ideals. As the scene grew and commercial interest increased, the quality varied. But the best ones set a standard that the current retreat scene has, in many ways, inherited.

The industry's own professionalization efforts ran in parallel. VLOS, founded in 1997 as the advocacy organization for the smartshop sector, facilitated training and education for smartshop staff. The Jellinek addiction medicine institute in Amsterdam developed a dedicated smartshop staff course, covering harm reduction, product knowledge, and how to recognise when someone should be turned away. A sector taking this kind of structured approach to its own workforce is not the usual picture of a drug trade.

What was happening in the smartshops was part of a wider psychedelic culture that extended well beyond mushrooms. MDMA was enormous in the nineties. There were legendary parties in converted church spaces in Amsterdam, and gatherings at Ruigoord, the squatted village near the Amsterdam port where the Landjuweel festival drew people who thought of psychedelics as part of a broader search for something. Later, around 2010 and 2011, the European festival circuit grew into something large and recognisable, with Boom in Portugal and Ozora in Hungary becoming major gathering points for a psychedelic community that now stretched across the whole continent.

People came to the Dutch cities from across Europe specifically to buy what they could not find at home. Italians, French, Germans, people from further afield. The smartshops stocked more than mushrooms. Iboga root bark was available well into the 2000s. Salvia divinorum was sold openly. 2C-B circulated, initially sometimes under the counter. Research chemicals and analogues appeared as each compound was successively banned. For a period, a remarkable range of altered states was openly and legally accessible in the centre of Amsterdam, alongside serious usage information and staff who had actual experience with what they were selling.

Around 2000, a parallel culture of home cultivation was quietly building. Grow kits for mushrooms could be ordered by post. It was entirely legal in the Netherlands to grow San Pedro cactus, to cultivate Salvia divinorum, and to grow Rivea corymbosa, the morning glory species whose seeds the Aztecs knew as ololiuqui and whose LSA content makes them a natural relative of LSD. I grew all of these myself for a period in the early 2000s. The line between the commercial smartshop scene and a broader culture of independent psychedelic cultivation was porous, and knowledge moved freely between them.

Ayahuasca circles were already well established before the end of the 1990s. The Santo Daime and the Uniao do Vegetal had been operating in the Netherlands for years, but beyond the formal churches, a number of individuals were offering different brews in informal settings, some coming from South American lineages, others self-taught. The plant medicine scene that gathered around Psychoactivity 2002 was already years in the making.

A less visible thread ran through university chemistry departments. I came to know three chemists, all university students or recent graduates, with the equipment and knowledge to synthesize and extract psychedelic compounds. The first I met in 1998. These were not secretive or furtive people. They were enthusiastic, knowledgeable, and entirely open about what they were doing, embedded in the same intellectual community as everyone else. DMT moved across Europe through networks of people like this, extracted from plant sources, circulating through the same channels as the plant medicines and the smartshop products. Not long after, 5-MeO-DMT began appearing as well, a distinct and considerably more intense compound that had been documented in Shulgin's TiHKAL in 1997 and became increasingly available in the early 2000s before most European jurisdictions moved to control it.

One of the less well-known aspects of this era was how seriously the Dutch took drug safety at the level of the party scene. Unity, the Dutch harm reduction organisation, ran drug testing services at parties and events throughout the nineties and beyond, offering on-the-spot or rapid laboratory analysis so that people could know what they were actually taking. A related project called Just Say Know, a deliberate inversion of the American Just Say No campaign, had formalised five testing centres in Amsterdam alone by 1992. When toxic adulterants appeared in MDMA pills in later years, the Dutch warning system, a direct heir of these early initiatives, issued public alerts that prevented deaths. The same pills killed people in the United Kingdom, where no equivalent system existed.

During this period I was completing my psychology studies, for which I had two research components. One was a literature study on ayahuasca, which I have published elsewhere on this site. The other was an empirical study that was only possible in the Netherlands at that time. I interviewed 90 people who had each used psilocybin mushrooms at least five times, with an average of ten experiences each. All had bought their mushrooms legally at a smartshop, in most cases receiving usage instructions at the counter. Not a single case had produced lasting psychological harm. Difficult experiences occurred, as they always do with any deep psychedelic exposure, but difficult is not the same as harmful, and with appropriate context, information, and support, the risk profile was far better than the public narrative suggested.

The Psychoactivity conference series gave this community a formal gathering point. Psychoactivity 1998 at the Royal Tropical Institute of Amsterdam brought together many of the most prominent psychedelic researchers and thinkers of the time. Albert Hofmann appeared as an unexpected guest, gave a speech, and then, at ninety-two, stayed at the Melkweg dance club until three in the morning. Psychoactivity 3 returned to Amsterdam in November 2002, this time built primarily around ayahuasca, where an active community was already experimenting with all kinds of plant medicines. I was there as a volunteer.

In the final months of my studies I began working at the drug research centre in Utrecht, the Centrum voor Verslavingsonderzoek, under Van de Wijngaart and Verbraeck, and continued there for eight months in total. We attempted to secure funding for a programme using ayahuasca in the treatment of hard drug addicts. The preliminary evidence was already there, some of it from South America, some of it from the Dutch scene itself. The attempt failed, not because the science was considered unpromising, but because of insurance complications that made the liability structure impossible to resolve within the available time. The question that project was trying to answer is now at the centre of several major research programmes around the world. We were simply a decade too early.

By the time of the ban debate in 2008, VLOS reported that approximately one and a half million portions of mushrooms were being sold annually across the Netherlands. That is an enormous number. The ratio of serious incidents to doses sold was, as the industry pointed out, vanishingly small.

In the years after my studies I was also working in clinical settings, including addiction clinics. The picture was consistent. The problems I encountered were alcohol, heroin, cocaine, amphetamines. A handful of people came in with cannabis-related difficulties, almost exclusively with the newer, stronger strains. In years of clinical work I did not encounter a single case of lasting psychological damage attributable to psychedelics alone. That is not the same as saying psychedelics carry no risk. But the cases that arise almost always involve pre-existing vulnerabilities that were present before the substance was introduced. When someone with an undiagnosed fragility uses a psychedelic and experiences a crisis, the substance gets the blame. When the same person deteriorates on a prescription antidepressant, the disorder gets the blame. The asymmetry is not logical, and it has distorted the public understanding of psychedelic risk for decades.

During this period I was also creating settings in which people could have guided psychedelic experiences. Quietly and carefully, with preparation and follow-up. Similar gatherings were happening throughout the Netherlands, and in Germany, Switzerland, and England as well: small groups of people, often with therapeutic or spiritual intentions, working with plant medicines in contexts that were serious and considered. That tradition was never widely visible. But it never stopped. It is, in one sense, what all 285 retreat centres are now doing openly.

The mushroom era in the Netherlands ended in November 2008, when the government banned more than a hundred species of psychedelic fungi following several incidents involving tourists. What the legislation did not ban, through what is either a deliberate oversight or a remarkable legal accident, were the sclerotia of the same fungi, sold in smart shops as magic truffles. Truffles contain the same active compounds and produce the same effects. They remain fully legal today.

The Science Returns: Zurich, Barcelona, London

While the cultural community was building itself in Amsterdam, serious neuroimaging science was quietly resuming in several European laboratories. In Zurich, Franz Vollenweider had been investigating the psychological and neural foundations of altered states at the Psychiatric University Hospital since 1992, using PET imaging to map what psilocybin and ketamine actually do in the living human brain. He founded the Neuropsychopharmacology and Brain Imaging research unit in 1996 and the Heffter Research Centre Zurich in 1998. His work produced some of the most rigorous early evidence that the effects of psychedelics on consciousness were explicable in terms of specific neural mechanisms.

In Barcelona, Jordi Riba began researching ayahuasca in 1996 with his mentor Manel Barbanoj at Sant Pau Hospital. After several years of preparation and protocol development, they conducted in 1999 the first placebo-controlled clinical trial of ayahuasca ever performed, showing that it could be administered safely to healthy volunteers and opening the door to systematic human research. Riba went on to conduct the first neuroimaging studies of ayahuasca, to discover the neurogenic properties of the harmala alkaloids, and to co-author the first randomised controlled trial showing ayahuasca's rapid antidepressant effects. He published nearly 80 scientific papers before his death at the age of 51 in August 2020. His work was the foundation on which much of the current European ayahuasca science rests.

In the United Kingdom, Amanda Feilding of the Beckley Foundation built a scientific collaboration with David Nutt beginning in 2005. When Nutt moved to Imperial College London in 2008, that collaboration became the Beckley/Imperial Research Programme, with Robin Carhart-Harris as principal investigator. The first fMRI studies with psilocybin, published in 2012, produced the first images of the neural correlates of the psychedelic state in the living human brain. A year later, the Medical Research Council funded the first clinical study of psilocybin in depression, with results showing that two doses lifted depression in all twelve volunteers for at least three weeks. In Maastricht, Jan Ramaekers and Kim Kuypers were building one of Europe's most productive psychopharmacology research groups, expanding from early MDMA work into psilocybin, LSD, and microdosing.

Two Moments in Basel

Two conferences marked the symbolic return of psychedelics to public life. On January 13 to 15, 2006, the biggest psychedelic conference held up to that point took place at the Basel Congress Centre, with over 2,000 visitors from 37 countries gathering to mark Albert Hofmann's 100th birthday. Hofmann was present, gave a speech, and declared that in human evolution it had never been as necessary to have this substance as it was now. Two years later, the World Psychedelic Forum returned to Basel with another 2,000 attendees. These were the moment when a field that had been working in laboratories and on the margins announced to the wider world that it was back.

The Conference Era

The OPEN Foundation was founded in the Netherlands in 2007, and its first major conference, Mind Altering Science, took place in 2010 at the University of Amsterdam. Over a weekend that none of those involved had done before on that scale, it showcased the first results of two Swiss randomised controlled trials to an audience of over 450 people. The Interdisciplinary Conference on Psychedelic Research, ICPR, has been running biennially since, growing from 400 delegates in 2012 to nearly 1,400 at the 2020 virtual edition. In the United Kingdom, Breaking Convention launched in April 2011 at the University of Kent, founded by a small group of academics and bringing 500 to 600 delegates from 30 countries to its first edition. It has run biennially since, now in its thirteenth year.

These two European conference series represent something distinct. Their format deliberately spans hard science, anthropology, philosophy, law, art, and culture in ways that more narrowly clinical conferences do not. That breadth has roots in the psycholytic tradition of the 1950s and 1960s, which always understood that the substance was a catalyst rather than the treatment, and that what happened around the session mattered as much as the session itself.

The Netherlands Today

There is one more number worth pausing on. At the time of writing, the retreat booking platform Retreat Guru lists over 285 psilocybin retreats operating in the Netherlands alone. Across Europe as a whole, adding the ayahuasca retreats in Spain and Portugal, LSD analogue retreats that have operated in Germany, and smaller scenes in Austria, the Czech Republic, and elsewhere, the total runs considerably higher. A 2025 PLOS One study found 310 retreat operations internationally, with Europe accounting for a significant share. The Netherlands is the only country in Western Europe where psilocybin truffles are not merely tolerated or decriminalised but unambiguously legal. Retreat centres operate openly, with professional facilitators, medical screening, preparation and integration programmes, and a level of transparency that would be impossible in countries where the work still happens underground.

This did not come from nowhere. It is the direct descendant of the smart shop era, of the harm reduction culture that van den Hurk and others built from 1993 onwards, of the research communities at Maastricht, Amsterdam, and Utrecht that kept taking the questions seriously even when the funding was scarce, and of thirty years of a lively, serious, often contentious community that gathered at conferences and in living rooms to think together about what these substances meant and how they should be used. The legal retreats in the Netherlands are in this sense the practical realisation of what the smart shop era was pointing toward: a context-sensitive, preparation-focused, integration-supported approach to psychedelic experience, offered by people with genuine expertise, within a legal framework.

What Europe Contributed

I am persuaded that the psychedelic renaissance as it now exists would not look the way it does without the European tradition. The clinical foundation, the decades of psycholytic therapy at eighteen centres across five countries, was documented and preserved and eventually revived. The cultural infrastructure, the smart shops, the conferences, the harm reduction scene, the communities of researchers and practitioners who kept talking to each other through the dark years, gave the renaissance a place to land. The scientific work, Vollenweider in Zurich, Riba in Barcelona, Carhart-Harris and Nutt at Imperial, Ramaekers and Kuypers in Maastricht, built a body of rigorous evidence without which the current clinical programmes could not have obtained their approvals or their funding.

And the philosophical tradition mattered too. The psycholytic approach, with its emphasis on the therapeutic relationship, on repeated sessions embedded in ongoing psychotherapy, on modest doses and careful processing rather than one overwhelming peak experience, is a model that takes seriously the fact that insight alone does not produce change, that what happens before and after the session is as important as the session itself. That is the idea at the centre of my own work, and it did not come from nowhere. It came from a European tradition of thinking carefully about how these experiences are held.

Eighty years after Albert Hofmann's bicycle ride, the field has arrived at something that looks like a second beginning. That arrival was made possible by many things, but among them, quietly and persistently, was a century of European work that most of the world still has not heard of.