The 1968 film Psych-Out isn’t memorable for much more than featuring one of Jack Nicholson’s early roles, but as a document of its era it tells us plenty. Set in the hippie epicentre of San Francisco’s Haight-Ashbury district, LSD is central to the plot, with flower children preaching expanded consciousness while the squares worry that they’re frying their brains. Being a low-budget exploitation film, shock value of course wins out and the film inevitably ends in tragedy.

Fifty years later, we’re seeing a revival of scientific interest in psychedelic drugs such as LSD, psilocybin and mescaline. Seemingly overnight, drugs that have been illegal for generations are at the forefront of a wave of research into potential treatments for numerous conditions, with encouraging results. Why should these substances, which have previously been classified as dangerous and without value, face such a re-evaluation?

Psychedelics are understandably associated with their recreational use in the Sixties counterculture, but there was a time when there was genuine debate over the potential uses of such drugs. In fields from psychiatry to the arts to espionage, drugs such as LSD offered exciting new possibilities to be identified through research and experimentation.

When Swiss chemist Dr Albert Hofmann first synthesised LSD-25 at Sandoz Pharmaceuticals in 1943, he didn’t know what he had created. Jay Stevens, in his book Storming Heaven: LSD and the American Dream, presents this era as a race to create the next wonder drug, and Hofmann had been experimenting in the hope of perhaps creating a treatment for migraines. Instead he created a drug so powerful that a mere 250 millionths of a gram was enough to bring on massive hallucinations, making his bicycle ride home after that initial self-test into one of legend. However, while LSD was undoubtedly powerful, the usefulness of such power was not yet apparent, presenting Sandoz with the dilemma of whether to pursue research to find a use for it or to move on. They began to supply LSD to researchers under the market name Delysid, leaving it to science at large to find a way to use it.

If chemists were racing to discover a new wonder drug then they had no shortage of potential clients waiting for a chemical solution to their problems. High on the list were the CIA, who, along with the US Army, had been investigating new ways to gain an advantage through drugs and chemicals. In 1953 the CIA launched MK-ULTRA, a program to explore the use of drugs for mind control purposes. Being so powerful in such small doses, LSD had obvious advantages over other drugs for clandestine use, but the problem remained to find what uses there might be in practice. Declassified documents from this era, covered in Martin A. Lee and Bruce Shlain’s book Acid Dreams: the Complete Social History of LSD: the CIA, the Sixties and Beyond, detail the rollercoaster ride that the Agency would take with the drug, seemingly unhindered by the ethical constraints placed on other scientists. Brainwashing, incapacitation and extraction of secrets were just some of the uses tested by the CIA, with research even being conducted on unwitting staff members and, astonishingly, private citizens, all under the justification that the US must keep up with whatever the Soviets might be doing.

One area where the CIA’s theories overlapped with those of other scientists was the idea that a dose of LSD could make somebody insane. While the Agency explored this as a nefarious end in itself, some in the field of psychology saw LSD as causing a ‘model psychosis’ which could in turn allow them to learn about mental illnesses such as schizophrenia in a more controlled manner. Ultimately this approach would be challenged on the basis that it wasn’t the drug itself causing schizophrenic behaviours, rather it was the uncomfortable environments that the drug was being taken in. Researchers would expand upon this to identify ‘set’ and ‘setting’ as crucial elements of the LSD experience, and attempt to create positive therapeutic scenarios for LSD use.

In the late 1950s, personal LSD therapy sessions were starting to become relatively prominent, with psychiatrists giving the drug to patients in order to assist in unlocking repressed emotions. Cary Grant was the highest profile advocate of LSD treatment, announcing to reporters in 1959 that “I have been through a psychiatric experience which has completely changed me.” Such celebrity endorsement boosted the treatment’s popularity, but other artists had different ideas of what psychedelics might best be used for.

Aldous Huxley was best known as the author of the dystopian novel Brave New World when he first tried mescaline in 1953, an experience that he would document in The Doors of Perception. For the rest of his life Huxley would advocate for the visionary experience of psychedelic drugs, believing that the impact of such drugs given to the right people (namely artists and intellectuals such as himself and his peers) could change the world for the better. Huxley wasn’t alone in this ambition, but others would take a more egalitarian approach, letting the genie out of the bottle for better or worse.

When he first tried magic mushrooms, Dr Timothy Leary was a respectable professor of psychology at Harvard University. After that, psychedelics became the centre of his research. First was an experiment that gave psilocybin to convicts in order to reduce recidivism, with outstanding results. Then there was an experiment to compare naturally occurring and drug-induced religious experiences. Eventually Leary’s outspoken advocacy of psychedelics, and his corresponding unwillingness to behave in a manner expected of a Harvard scientist, would see he and his cohort expelled from the university, Leary instead becoming a kind of guru for the drugs. Where Huxley wanted to create change subtly, Leary wanted to kick the doors down. Soon psychedelics would become a part of popular culture, from Bob Dylan to The Beatles, and Leary would be labelled as “the most dangerous man in America”. The moral panic would reach a tipping point and the drugs would finally be made illegal in the US in 1966 with other countries to follow, stymieing those still researching other possibilities.

Now things appear to have settled down for psychedelic drugs. With less interest in both their mystical and their military uses (so far as we know), drugs such as LSD and psilocybin seem to have finally found their moment to be investigated for therapeutic use again. The image of the Sixties ‘acid casualty’ has been challenged by multiple studies finding that users of psychedelic drugs were at no greater risk of mental health problems than the rest of the population, according to a 2015 article in Nature journal. In a 2017 Psychology Today article, Jennifer Bleyer reported on numerous studies into the treatment of addictions using psychedelics, especially psilocybin.

It may seem counterintuitive to treat addiction to one illegal drug by using another, but maybe it’s not so far-fetched. One of the key steps in the Alcoholics Anonymous twelve-step program is the acceptance of a higher power – maybe the mystical school of psychedelics were on to something, and these drugs can unlock that? Whatever the basis, science is finally starting to win back some of the ground that was lost.