LSD's 75-Year Trip: How It Shaped Rock Music, Silicon Valley and the Whole of the 1960s | QDaily Business History

LSD was truly popular for barely a decade. Its influence has lasted ever since.

"I was looking at the buildings, looking out over San Francisco, thinking about Buckminster Fuller's idea that people believe the earth's resources are inexhaustible because they think the earth is flat. I'd taken a 200-microgram dose, and looking down at the city of San Francisco from 300 feet (100 meters) up, I thought: from here I can see the earth curve. I realized that the higher you stand, the more you can see that the earth is round."

That is Stewart Brand, author of The Whole Earth Catalog, in March 1966. He put the thoughts down to the 200 micrograms (one-fifth the weight of a grain of sand) of the hallucinogen LSD he had dropped. In the language of the day, this was a "trip."

This year marks LSD's 75th anniversary. On April 19, 1943, Swiss chemist Albert Hofmann and his assistant rode their bicycles home from his lab in Basel — the world's first complete LSD trip, later known as Bicycle Day.

Before setting out, Hofmann had drunk 250 micrograms of LSD diluted in water; his assistant later said they rode extremely fast. By Hofmann's account, the streets of Basel became a place where heaven and hell intertwined, and the neighbor delivering milk turned into a wicked witch. After the initial fright he began to enjoy the kaleidoscopic world — door handles and the sounds of passing cars turned into visions in front of his eyes. When he woke the next morning, Hofmann felt clear-headed; everything shimmered with a new luster, and even breakfast tasted better than usual.

Tens of millions of people have repeated that journey in the 75 years since. In the 1960s, when it was at its most popular, LSD directly catalyzed America's hippie movement and shaped a whole generation across the United States and Western Europe — their pop culture, and even the development of the personal computer. Steve Jobs once said taking LSD was one of the two or three most important things he had done in his life; shortly after the iPhone went on sale in 2007, he told a researcher over the phone: "Just pour it into the water supply and let everyone get high."

Of course, like the authors of many other important discoveries, Hofmann was not thinking that far ahead in 1943.

Hofmann was a chemist at Sandoz, the Swiss pharmaceutical company that later became Novartis. He had been studying lysergic acid — a compound secreted by the ergot fungus that grows on spoiled rye — hoping to develop a drug for fatigue. LSD (lysergic acid diethylamide) was the 25th molecule he synthesized. By Bicycle Day he had already worked on it for five years, and finally decided to try it himself.

Plenty of drugs can act on the human mind — marijuana, cocaine and mushrooms can all produce euphoria. But the LSD Hofmann synthesized is the most powerful hallucinogen in the world: a single dose of 100 micrograms, about one-tenth the weight of a grain of sand, is enough to trigger six to twelve hours of hallucination.

LSD is one of the cheapest illegal drugs. Anyone with a background in biochemistry can synthesize it, and a dose costing $2 to $3 lasts a long time. It is usually sold as drops on stamp-sized pieces of paper printed with cartoon characters or fantastical designs. Someone once described LSD as "a taxi that takes you to the party."

The journey LSD has taken as a drug is as charged as the effects it produces in people. From a scientific experiment, to a tool the CIA used for mind-control research, to the fuel of the Summer of Love — all in the space of 20 years.

Unlike heroin, LSD is not addictive. The U.S. National Institute on Drug Abuse (NIDA) describes it this way: "It is not considered an addictive drug since it does not lead to uncontrollable drug-seeking behavior."

But not long after it gave rise to the sweeping hippie movement of the 1960s, LSD was banned by governments around the world and, like that movement, vanished from the mainstream. The controversy around it meant its influence was deliberately erased. Today it is easy to forget — and even hard to understand — how readily young people once welcomed hallucinogenic drugs.

Seventy-five years on, LSD is coming back. More young Americans are buying it through one channel or another. At the same time, scientific research into LSD has been picked up again in recent years, exploring its effects on the brain and its medical possibilities. Each new finding is a reminder of how little we know about this creation that shaped a generation.

"Turn On, Tune In, Drop Out" — Timothy Leary, former Harvard professor

Hofmann, who died at 102, once called LSD his "problem child": within a few years of its accidental synthesis the drug had strayed from the purpose he first developed it for, and, thanks to the efforts of a few evangelists, entered the clinical testing ground that was humanity itself.

Timothy Leary, a psychology professor at Harvard, was one of the era's hardest-working promoters of LSD. American media treated him as the drug's spokesman, and Nixon called him "the most dangerous man in America." In the summer of 1960, having just been through his second divorce and the suicide of his first wife, Leary tried Mexican magic mushrooms for the first time at a resort in Mexico. Back at Harvard, he began researching psilocybin, the mushroom's main psychoactive compound. He and assistant professor Richard Alpert ran experiments on student volunteers and prison inmates, hoping this natural hallucinogen could teach people to be good, much as religion does.

Introduced to LSD by an Englishman named Michael Hollingshead, Leary was completely won over. He dropped psilocybin and turned to LSD instead. But his approach diverged from both the scientists' and the CIA's — he fell into a religious fervor and began remaking himself into an "LSD expert." He wrote the widely circulated psychedelic manual The Psychedelic Experience and gave interviews everywhere.

Semi-synthetic hallucinogen LSD (molecular formula: C20H25N3O)

Name

Lysergic acid diethylamide (LSD)

State

Pure LSD is a colorless, odorless solid with a faintly bitter taste

Dose

100 micrograms per dose, about one-tenth the weight of a grain of sand

Price

$2 in 1965 (about $16 in 2018)

Users

1960s hippies, musicians, Hollywood figures, scientists and others

Reach

24.73 million Americans have taken LSD at some point in their lives — 2012 U.S. National Survey on Drug Use and Health

To prove LSD held extraordinary power, Leary claimed its discovery had come almost at the same moment as humanity's first nuclear fission test. That, he said, was because God, once humans had invented the power to destroy the earth, had opened a new door to save them.

Leary quickly became a favorite of New York's rich and famous. By then Harvard had already fired him for testing LSD on students.

Before he arrived in San Francisco, Leary had no particular liking for the West Coast; he presented himself as a serious academic running psychological experiments. Even so, at the 1967 "Human Be-In" — a gathering of hippies in Golden Gate Park — Leary seized his moment. He spoke to the dense crowd of young people, and at the end he pronounced, word by word, the three famous phrases that would describe the LSD experience and work like a religious slogan: Turn on, tune in, drop out.

In 1965, possessing LSD was not illegal — only making it was. But by 1966, New York, California and several other states had made possession a felony. By 1969, federal law banned LSD outright, a new commission was set up to enforce the anti-psychedelic legislation, and LSD was moved out of the Food and Drug Administration's jurisdiction.

To protest the new LSD bans in California and New York, thousands of hippies — described by California Governor Reagan as people who dress like Tarzan, have hair like Jane and smell like Cheeta — held the "Love Pageant Rally" and the "Human Be-In" in San Francisco's Golden Gate Park in October 1966 and January 1967.

The anti-psychedelic laws sharply increased young people's already ungovernable appetite for LSD.

By then San Francisco had drawn more and more free-living young people. As rents rose, they moved to the cheaper Haight-Ashbury district, next to San Francisco State University. In the mid-1950s the city had already been a gathering place for the idols of the Beat Generation — poets founded the City Lights bookstore here, and Allen Ginsberg read the poem that shook America, "Howl": "I saw the best minds of my generation destroyed by madness, starving hysterical naked, dragging themselves through the negro streets at dawn looking for an angry fix."

Before San Francisco became the stage of the hippie movement, the most popular drug in its artist circles was marijuana, which works more like a stimulant and is far milder than LSD. LSD, at the time, was used by only a handful of people.

Among them: Aldous Huxley, author of Brave New World; media mogul Henry Luce; the French philosopher Michel Foucault; folk singer Bob Dylan; the film actor Cary Grant. Nearly every Beat poet and jazz musician had been through an LSD trip too, but most of them used it simply to boost creativity, or as a sensory thrill.

LSD was about to jump out of this small circle into San Francisco as a whole, and then into American society. Footage of Leary's speech at the "Human Be-In" spread across the country through newspapers and television; the smiles of 20,000 outlandishly dressed young people were frozen in one medium after another. The press announced that this crowd nourished by psychedelics would be the "generation of love," and that the summer of 1967 would be the "Summer of Love."

By Leary's later estimate, around 25,000 Americans had taken LSD in 1962; by the end of 1965, a survey put the number at nearly 4 million, 70 percent of them in high school or college.

That much demand leaves a question: who was making it all?

In 1966, under pressure, Sandoz withdrew the investigational new drug application it had filed for LSD, and that May it stopped production. What actually flooded music venues with LSD was a set of underground chemists who handed it out without chasing profit.

In Breaking Bad, the meth cooked by Walter White's other self, Heisenberg, is so pure it comes out sky-blue. That detail almost certainly comes from Augustus Owsley Stanley III, known to everyone as "the Honorary Mayor of San Francisco." Stanley improved on Sandoz's yellowish LSD; his purified product was colorless, and shaken in the dark it would even glow on its own.

Stanley, an amateur chemist, priced his product at $2 a dose (about $16 today), which left him almost no profit. The 100,000 cheap doses he sold "wrecked" the market before the gangs could take over California's psychedelic trade. Marty Balin of Jefferson Airplane later said in an interview that at their shows they would bring a bag of LSD and throw it into the audience the way you scatter M&M's.

In the Oxford English Dictionary, Stanley's middle name, "Owsley," has become a byword for especially pure psychedelics. Between 1965 and 1967, Stanley alone made enough LSD for 5 million doses. To tell the batches apart he dyed them different colors — like the "Monterey Purple" of the 1967 Monterey Pop Festival.

Several of his apprentices had signature products of their own, such as Nicholas Sand and his "Orange Sunshine." In a 2009 National Geographic documentary about LSD, Sand said that over his whole "career" he had made about 30 pounds of it — enough for 140 million trips.

Stanley had been a radio operator in the U.S. Air Force, worked at the Jet Propulsion Laboratory in Pasadena, California, and moonlighted as a broadcast engineer at a radio station. In 1963 he moved to Berkeley, hoping to sit in on classes at a university then in the middle of anti-Vietnam War protests. There he met the chemistry-major girlfriend who would later make LSD with him, and took LSD for the first time. That same week, he heard the Beatles for the first time.

"It all seemed to come together," Stanley told Rolling Stone.

This "Honorary Mayor of San Francisco" was the first backer and the sound engineer behind the Grateful Dead, one of the leading psychedelic rock bands. His most famous piece of live-sound engineering was the Wall of Sound system he designed for the band in 1974: 75 tons, 26,400 watts of continuous power, the largest and most advanced stage sound system in the world at the time. Amplifiers, speakers, subwoofers and tweeters were stacked three stories high.

"One pill makes you larger, and one pill makes you small" — Grace Slick of Jefferson Airplane, "White Rabbit"

Genres in pop music have always ended up entangled with drugs. Jazz and heroin, hip-hop and cocaine, punk and amphetamines — and, as the name makes plain, psychedelic rock.

The mixture of music and drugs brought the undercurrents of 1950s British and American society to the surface: anti-war feeling, anti-nuclear thinking, and every kind of countercultural work, poem and song was growing. Rather than turn to jazz, which had become too introspective, too complex, too elite, the new generation of musicians added to the recipe for rock and roll instead, dropping in amphetamines and later LSD.

Zhang Tiezhi, author of Sound and Fury (《声音与愤怒》), described the era this way: "Music history entered a new tunnel right about then: folk began to fade, Dylan plugged in, and the Beatles moved from bubblegum songs to more mature, more complex rock. San Francisco's hippies began combining blues, folk, country and a 'psychedelic' feel to create what was called the San Francisco Sound: psychedelic rock."

The Grateful Dead's music suited the taste of people on an LSD trip especially well — the band went on stage high and won audiences over with long stretches of improvisation, every song running past five minutes. Their concerts stretched, famously, to five hours, and their deal with Warner was not written the usual way, by number of songs, but "per three and a half minutes."

In fact the San Francisco Sound of the Grateful Dead and Jefferson Airplane was only one branch of psychedelic rock, the one built on live performance. The other branch, represented by the Beatles and Donovan, was pop psychedelia built on studio technique.

Remember Michael Hollingshead, the Englishman? He went back to England carrying Leary's The Psychedelic Experience and 5,000 doses of LSD, and many British rock musicians had their first trip because of him. Of all of them, the Beatles left the deepest mark on psychedelic rock.

Starting with Rubber Soul in 1965, the Beatles' lyrics stopped being only love songs. In "The Word," the idea of love goes beyond descriptions of sex in the corner of a gasworks; "Nowhere Man" examines the inner life under the psychedelic experience; "She Said She Said" was inspired by Lennon's second trip; guitarist George Harrison picked up the Indian sitar for the first time; and the lyrics of "Tomorrow Never Knows" come almost entirely from Leary's The Psychedelic Experience.

In June 1967 the Beatles released their eighth studio album, Sgt. Pepper's Lonely Hearts Club Band, which many consider their most important record. Lennon never admitted that "Lucy in the Sky with Diamonds" was really a nod to LSD, but the fans believed it anyway — the Beatles tribute film Across the Universe used the song to close the picture, with dreamy, halo-lit images. The BBC did, however, ban another song from the album, "A Day in the Life," because it mentioned "a trip."

To recreate the distorted sensations of an LSD trip, the Beatles began putting all their energy into the studio; August 29, 1966 was their last public concert. What they and the brilliant producer George Martin made in the studio meant records were no longer just recordings of live performance. Pop music had truly entered the age of the album.

Simon Napier-Bell, a record producer active in the '60s and '70s, summed up the change psychedelic music brought from the industry's point of view. "The real force behind the psychedelic revolution came from the record companies," he said. "Psychedelic music was album music, and an album cost four times as much as a single. LSD may be the most fitting drug name of all — the pounds (Librae), shillings (Solidi) and pence (Denarii) it generated began to reshape the industry completely."

Album rock — the term rock historians use for exactly this change in the music of the mid-1960s.

The record labels naturally welcomed a new era of surging profits, and the festival stage became the place where psychedelic rock musicians started leaving hippie life behind. Jefferson Airplane went to Los Angeles to record, signed with RCA Records, and lived more and more like rock stars. The 1967 Monterey Pop Festival was a springboard for several West Coast bands going commercial: Columbia Records signed Janis Joplin, the singer of Big Brother and the Holding Company, while Elektra Records took Love and the Doors. Rock and roll made the record companies enormous sums, and the industry consolidated over the following years.

If psychedelic rock was the soundtrack of San Francisco's hippie movement, then Ken Kesey, author of One Flew Over the Cuckoo's Nest, and the "Merry Pranksters" he put together were the party's hosts. For these young students, who drove an old school bus across the country playing rock music and handing out free LSD, the meditation sessions and seminars Leary held at his New York mansion were far too dull. They only wanted to throw a party.

Carrying the "Honorary Mayor of San Francisco's" product, Kesey and his friends staged "Acid Tests" and rock shows all over California. In the few months after the end of 1965, more young people probably had their first LSD trip than had taken part in the CIA's experiments or Leary's research over the previous decade combined.

The psychedelic rock most deeply marked by LSD

The Beatles

"Lucy in the Sky With Diamonds"

Jefferson Airplane

"White Rabbit"

The Beatles

"Tomorrow Never Knows"

The Doors

"The End"

Jimi Hendrix

"Purple Haze"

Pink Floyd

"Comfortably Numb"

Queen

"Bicycle Race"

The Beatles

"Strawberry Fields Forever"

…

"If we're too afraid of a drug, we send it to San Francisco" — a CIA intelligence officer

The shadow of violence over the Altamont Free Concert staged by the Rolling Stones in 1969 brought the party to the worst possible end, and the world that met the 1970s was still a bad one.

Whether it was the peacefully resisting hippies or the New Left radicals who took to the streets, this movement, aimed at winning civil rights and ending the war, paused in 1975 when the United States pulled out of Vietnam.

The drugs were banned and the young people grew old. Some of them fell in behind President Reagan in the 1980s, created neoconservatism and became "yuppies." Economically they turned conservative and materialistic, but they were still unwilling to be absorbed on social values — in the 1990s they elected Clinton.

Also in 1975, top-secret CIA documents were released under the Freedom of Information Act, and only then did people learn there had been a hidden thread running before the movement broke out: the CIA's use of LSD in mind-control experiments.

The project, named MK-Ultra (MK for Mind Control), was a top-secret Cold War test run by the CIA, and it is also the backdrop of Stranger Things, the Netflix series that has been a hit these past couple of years.

Turn the clock back to a year before the Swiss chemist Hofmann's bicycle ride. Thousands of miles away in Washington, D.C., a group of American scientists began working on a "truth drug" under orders from the Office of Strategic Services (OSS), the CIA's predecessor. They tried caffeine, alcohol, barbiturates and mescaline; marijuana looked promising for a while but did not work out either. Hofmann's report, published in 1947, convinced them that LSD — colorless, odorless, effective in tiny doses — was the truth drug they had been looking for.

So a series of secret programs under different code names got underway, and large sums of money poured into the MK-Ultra project to fund the CIA's tests on human subjects. Stansfield Turner, the 10th Director of the CIA, later testified that 44 universities, 15 research foundations and pharmaceutical companies, 12 hospitals and clinics and 3 penal institutions across the country had been hired to carry out MK-Ultra research, with Stanford University and UC Berkeley the two best-funded of them all.

The CIA's initial interest in a truth drug was to help with interrogation. One report shows the agency once gave LSD to a senior U.S. military official, who then gave up a top military secret. But as the experiments went further they found that LSD made subjects hallucinate, so what the subjects confessed was quite possibly wrong. The CIA then began studying it as a counter-interrogation drug instead, and often dosed servicemen without telling them, just to watch their reactions.

Frank Olson, a chemical researcher for the U.S. Army, drank whiskey the CIA had laced with LSD in 1953 and fell to his death from a tenth-floor window. President Ford later apologized to Olson's widow in person and paid her $750,000 in compensation.

"If we're too afraid of a drug to test it on our own people, we send it to San Francisco."

Seymour Hersh, the investigative reporter, revealed in a 2012 report that the CIA had at least three testing sites in San Francisco disguised as brothels, in an operation code-named "Midnight Climax." Female agents would lure residents from local bars to these sites, dose them with LSD and observe how they reacted.

The program did not end until 1964.

Looking back at LSD's history, the interesting part is how one synthetic compound was used and understood by different groups — as a source of inspiration, of escape, or of terror.

What the CIA created was terror, plainly. But a run of research at Stanford University produced another set of people: those LSD inspired.

"Just pour it into the water supply and let everyone get high" — Steve Jobs, founder of Apple

Myron Stolaroff — a member of a personal-computer club, a Christian, and a Stanford master's in electrical engineering — founded the International Foundation for Advanced Study in the Bay Area in 1961 and began LSD experiments there. Over the next five years the foundation guided more than 350 people through a "trip," many of them important pioneers of computing, among them Douglas Engelbart, the inventor of the mouse.

The clinical report on the first 153 LSD subjects reads rather like an infomercial: after taking LSD, 83 percent of subjects reported lasting beneficial effects. The behavioral improvements listed included a 78 percent increase in the capacity to love, 69 percent better at defusing hostility, 69 percent better communication, 88 percent better understanding of oneself and others, 72 percent better relationships, 66 percent less anxiety, 71 percent more self-confidence, and 83 percent who saw the world with new eyes.

Today, Silicon Valley's image tends to be tied to words like startup, rebellious, free and casual.

But when LSD first caught on, Silicon Valley and the whole computer industry were still a suit-and-tie business.

Computers were first built to break codes and calculate weapons trajectories; when they went commercial, only big companies could afford them. IBM was the largest computer company, and most of the industry's capital and customers were on the East Coast. Before the personal computer boom of the 1970s, Silicon Valley — which had already gathered a fair number of tech firms — was a place that served the military and large enterprises too.

What finally broke that world open was a group of people who had been deeply shaped, in their youth, by hippie culture.

Apple's famous "1984" ad is a picture of that victory. On the giant screen in the ad, Big Brother is speaking: "Today, we celebrate the first glorious anniversary of the Information Purification Directives..." The followers below sit as blank as if they had been lobotomized, until a young woman in a white shirt and red shorts runs in and hurls a hammer at the screen.

Stewart Brand, who later founded The Whole Earth Catalog, was among the first subjects at the International Foundation for Advanced Study. Not long after, he visited the Stanford computer center and watched researchers lost in "Spacewar!," one of the earliest video games ever made — a group of young men so absorbed in the computer that their souls seemed to have left their bodies. It gave Brand a first, hazy sense of what would years later be called "cyberspace."

Jobs, deeply influenced by Brand, is one of the most influential tech figures to have admitted taking LSD publicly. In a 2001 interview, while showing off the newly developed iTunes program on a Macintosh, he told a reporter he had always believed that taking LSD was one of the two or three most important things he had ever done.

Bill Gates, who helped Jobs make the personal computer universal, had taken LSD as well. Asked about it in a 1994 Playboy interview, he said that before he turned 25 he had done "things he never went back to later in life."

Like Gates, Jobs in fact stopped taking LSD after founding Apple at 21. "Once Apple started, Steve was very focused on making it successful... he didn't need psychedelics," said Daniel Kottke, a computer scientist and one of Apple's earliest employees, in an interview given after Jobs's death. Back then, both of them had read Be Here Now — written by none other than Richard Alpert, the assistant professor who had researched LSD with Leary at Harvard.

But Jobs made no secret of it in later life either. At the request of his friend Rick Doblin, Hofmann wrote to Jobs in 2007, hoping he would fund the LSD research of the Swiss psychology PhD Peter Gasser — the first psychotherapy study of LSD since the drug had disappeared from view. The letter led to a phone call between Jobs and Doblin, head of the Multidisciplinary Association for Psychedelic Studies (MAPS). Jobs never did fund the research, but on the call he still said: "Just pour it (LSD) into the water supply and let everyone get high."

Of course, an enormous number of people have taken LSD, and Gates and Jobs are only two of them. The personal computer's arrival also rested on the chip breakthroughs of the 1970s — Intel's success in pushing Moore's Law forward is what made cheap computers possible.

But when it comes to how a technology actually takes shape, nothing is inevitable. The structure of the World Wide Web, the appearance of the mouse, the human-computer interface the Macintosh made ordinary, the multi-touch interaction that began with the iPhone — every one of them was the result of particular people making particular choices at particular moments.

The generation that made those choices, and the people whose ideas influenced them, were a generation deeply shaped by hippie culture. They chose "personal" as the future of the computer. As Brand later wrote in "We Owe It All to the Hippies": "The counterculture's scorn for centralized authority provided the philosophical foundations of not only the leaderless Internet but also the entire personal-computer revolution."

Even Timothy Leary came forward to endorse the personal computer, rewriting his famous line in the '90s as "Turn on, boot up, jack in".

That culture is still visible today. The slides in Google's offices, Zuckerberg's hoodies and T-shirts — these are Silicon Valley's heirs telling the world they are not like the old guard, even though they have in fact become the new giants, the new monopolists, wielding influence IBM never had.

LSD is popular in Silicon Valley again, but its users are no longer trying to open their minds. Like the place itself, they have become people who chase efficiency.

Silicon Valley engineers have taken to microdosing about 10 to 20 micrograms of LSD, with the aim of "improving work performance." Between 2015 and 2017, the Financial Times, Rolling Stone, GQ and Wired, among others, all reported on it. Diane, a 29-year-old startup founder, said she "doesn't drink coffee, just takes LSD"; Mike, a 25-year-old researcher at UC San Francisco, said: "I'd actually be more nervous about letting slip that I had a Coke last night than about telling a coworker I took LSD over the weekend."

In Silicon Valley LSD has become another kind of "smart drug" (the usual ones are built on the stimulant amphetamine), just as it was once fashionable on Wall Street.

Some of the scientists and Silicon Valley figures who have openly admitted taking LSD (a partial list)

Founder of Apple – Steve Jobs

Founder of Microsoft – Bill Gates

Founder of quantum electrodynamics, Nobel laureate in Physics – Richard Feynman

Inventor of the mouse – Douglas Engelbart

Discoverer of the polymerase chain reaction, Nobel laureate in Chemistry – Kary Mullis

Author of the term "artificial intelligence" – John McCarthy

Back to the Lab

LSD is returning to the laboratory. The institutions doing the research include New York University, Johns Hopkins University, UCLA, the University Hospital of Psychiatry Zurich and Imperial College London, among others.

A 2016 study at Imperial College London was pivotal. It was the first to use brain scanning to show how LSD acts on the brain, and it found that after volunteers were injected with (rather than swallowed) 75 micrograms of LSD, parts of the cortex that do not normally handle vision began processing images as well.

Dr. Robin Carhart-Harris, who led the study, explained: "Normally our brain consists of independent networks that perform separate specialised functions, such as vision, movement and hearing – as well as more complex things like attention. Under LSD the separateness of these networks breaks down, and instead you see a more integrated or unified brain."

"Our interpretation is that LSD reduces your overall sense of self," said Katrin Preller, a psychologist and researcher at the University of Zurich.

Put simply, LSD dissolves the self and makes it easier to feel other people and one's surroundings, which is why LSD users in the past described a sense of merging with the world.

David Nutt, professor of neuropsychopharmacology at Imperial College London, thinks LSD's effects can be seen as reversing many of the limits on thinking we build up between infancy and adulthood. Nutt said excitedly that they had waited 50 years for this result, and that for neuroscience its importance was "the equivalent of the Higgs boson for particle physics."

Scientific research on LSD stopped dead in the 1970s. Before that, the academic world had held four scientific conferences on its therapeutic potential and published thousands of papers. But media attention shifted to the ugly side of the hippie movement (some students jumped out of windows after taking it) and to LSD's popularity inside the U.S. military, which pushed Nixon, once in office, to enact a federal law banning LSD outright.

In 1969, the Bulgarian psychiatrist Marina Boyadjieva, who was still pressing on with LSD research, finished her dissertation — "Experimental Psychiatric Research through LSD-25-Induced Model Psychosis" — and with it earned her doctorate in medical science from Sofia Medical University. When she wanted to take the research further at the military's request, Mr. Burch, the Sandoz representative who had long supplied her with LSD, told her: "I'm sorry, madam, we have destroyed our entire stock."

Because so much of the research was concentrated in the United States, once the U.S. banned it, drug companies had no reason to keep making LSD. Soon no research project anywhere could get hold of any. In 1971 the UN Convention on Psychotropic Substances required signatory countries to ban it. Individuals could still buy LSD easily enough through one channel or another, but scientists could not. As Jay Stevens, author of Storming Heaven: LSD and the American Dream, put it: "What really ended in the '60s was scientific research into LSD."

Oscar Janiger, an experimental psychiatrist who ran LSD research in the 1960s, wrote in a 1999 article that his work found some artists who took LSD had a "learning curve" — they gradually found ways to look for creative inspiration while under its influence. But he said that "even 45 years after I began my research, there is still no scientific consensus clearly defining the core elements of LSD, nor any research clarifying the specific mechanism by which LSD stimulates creativity."

After 2000, scientists started looking for a substitute for LSD, turning to psilocybin, the main psychedelic compound in the magic mushrooms Leary first tried. "One of the great things about psilocybin is that it's hard to spell, and it hasn't received the same negative publicity," said Bill Richards of Johns Hopkins University.

At a "Psychedelic Science" symposium held in Oakland, California in May 2017, scientists from around the world gathered to discuss the medical value of various psychedelics. Amanda Fielding, a British activist working to lift drug prohibition, said: "These compounds have become deeply taboo. To bring them into society we have to use the best scientific evidence to show how they act on the brain and how they can benefit people."

"If unpredictability is still a feature of this drug, it will be hard for it to enter society," Grace Slick of Jefferson Airplane said in a documentary about LSD. "On the one hand I'd say it's a 'wonderful enlightenment.' On the other, 'be careful,' because you might jump out a window. That's the problem — you don't know what's going to happen."

In Basel, Switzerland, this year's 75th-anniversary event for LSD also invited researchers from around the world. The full day's topics included "New Clinical Research on LSD," "LSD and Schizophrenia / Psycholytic Therapy," "LSD and Creativity," "Memories of Living with Albert Hofmann," and "When Will LSD Become a Prescription Drug?" At a conference about a single drug, you will rarely find discussion as tangled up with science, mysticism and history as this.

Perhaps one day this drug will shed its history and become a standard treatment like morphine. Whether or not anyone else accepts that, it is at least what Hofmann himself hoped for.

Hofmann later took Timothy Leary to task: "I discussed the problem with him. I said, you should not tell everyone, even children, to try LSD. LSD can hurt you, drive you mad. But used properly, psychedelics can stimulate the kind of 'visionary experience' we had as infants and lost as we grew up."

On his 100th birthday in 2006, Hofmann gave a television interview in which he said he still took LSD now and then. "Now most people live in big cities, in a dead world," he said. "They have landed on the moon, but they don't even know how to look at the stars."