After taking mescaline, a powerful psychedelic, in 1953 Aldous Huxley wrote: “Visionary experience is not always blissful. It is sometimes terrible. There is hell as well as heaven”. Many demons appeared in early experiments with psychedelics in the 1950s, most of which centred around lysergic acid diethylamide – LSD. Scientists believed they were witnessing a temporary psychosis in subjects, and the first reports to reach the public portrayed the drug’s effects as a terrifying experience.

But then there was heaven. The “miracle, moment by moment, of naked existence,” as Huxley put it. Beyond personal discovery, the flip side of LSD led researchers to explore whether it could treat alcoholism and various mental illnesses. Despite some success, research into the medical benefits of psychedelics was stopped in the 1970s – until today.

Scientists at Imperial College London are carrying out small-scale human trials using psilocybin (the active ingredient in magic mushrooms) to treat depression. The results are impressive: one study took 12 volunteers with severe depression, who had not responded to any other treatment, and gave them two doses of psilocybin. In all volunteers depression was lifted for three weeks; in half the volunteers it was lifted for several months. The most recent study, published last month, used fMRI brain imaging to understand these effects, and found a clear and lasting change in brain activity. “Several of our patients described feeling ‘reset’ after the treatment and often used computer analogies,” said Robin Carhart-Harris, Head of Psychedelic Research at Imperial College. “For example, one said he felt like his brain had been ‘defragged’ like a computer hard drive, and another said he felt ‘rebooted’”.

But psilocybin is a Class A drug in the UK, so cutting through red tape to achieve these results required years of patience while the group sought the approval of regulators and hospital ethics committees. “It cost £1,500 to dose each patient, when in any sane world it might have cost £30”, said Professor David Nutt, the outspoken director of Imperial College’s Neuropsychopharmacology Unit. Nutt was sacked from his position as chief drugs adviser to the British Government in 2009 after criticising the decision to reclassify cannabis from Class C to Class B. He also wrote that taking ecstasy was safer than horse riding – which, at least statistically speaking, it is.

Government approaches to drug legislation are rarely evidence based. The United States’ ban on cannabis in the 1930s was driven by xenophobia towards Mexicans, while Richard Nixon’s War on Drugs in the late 1960s was, as much as anything, a political tool against “blacks and hippies”. Nixon’s dogmatic stance against drug-taking also shutdown scientific research into the effects of these powerful substances. The United Nations 1971 Convention on Psychotropic Substances classified LSD and psilocybin as Schedule 1 drugs that have no current therapeutic value – tying the hands of researchers around the world. Ecstasy joined the Schedule 1 classification in the mid 1980s (around the same time that rave culture emerged), despite showing promise as a treatment for post-traumatic stress disorder.

For decades, medical research into therapeutic uses of these drugs has been stuck in a catch-22. Laws restrict experiments that could demonstrate medical benefits and so, lacking in evidence, the drug remains classified as having “no known medical benefits”.

This is not to say that these powerful and influential chemicals can’t cause a lot of harm. As noted, early LSD experiments in hospital rooms led many towards hell. Psychedelics are very susceptible to what psychologist Timothy Leary coined “set and setting”. Set is the mindset of the person, their mood and expectations of the experience, while setting is their physical and social environment. The worst cases of abuse were committed by the CIA, who wanted to develop LSD for chemical warfare or, perhaps, a truth serum. In bare rooms under bright lights people were secretly dosed and then interrogated; if they didn’t give up their secrets, they were told that their trip would be extended indefinitely.

Even as the medical benefits of psychedelics began to emerge, over zealous use of LSD by psychologists in the 1950s and 1960s left plenty of patients a mental wreck. In a rare example of evidence based policy, cases like these led the sale and manufacture of LSD to be first banned by Congress in 1965 – several years before Nixon’s Drug War. LSD, like all drugs (and in fact all technology), is neither good nor bad. It depends on how it is used.

Dogged efforts by the researchers at Imperial College (among other institutions) are beginning to change the perception that illegal drugs are primarily harmful. One of the most captivating scientific images of 2016 was a brain scan of volunteers taken while tripping on LSD. You can also see this shift reflected in the recent legalisation of cannabis for medical purposes across most American states and in turn other parts of the world. Of course, the medical benefits of cannabis have been known for millennia. As far back as 2737 B.C., the Emperor Shen Neng of China was prescribing cannabis to treat gout, rheumatism and malaria; while the plant remains vital to the toolkits of traditional healers the world over.

Scientific evidence that cannabis can alleviate the debilitating symptoms of multiple sclerosis and chronic pain is now conclusive. And the list of potential medical uses, from epilepsy to autism, continues to grow. Some treatments are backed up peer-reviewed research, others only anecdote – and it could remain that way for some time as researchers try to unravel the complex compounds inside cannabis. The plant contains more than 500 chemicals, and over 100 of these are active in the human body. There’s tetrahydrocannabinol (THC) which gets you high, and cannabidiol (CBD) which doesn’t. But all these “cannabinoids” have an effect of some kind on the systems that regulate pain-sensation, mood, memory and appetite. To confuse matters further, each strain of cannabis will contain different amounts of each cannabinoid; some strains work for some conditions, others don’t.

Despite this growing body of evidence, in the United States cannabis is still a Schedule I substance under federal law and still classified as having “no currently accepted medical use”. As with psychedelics, this hinders research and prevents evidence that could reclassify cannabis. For example, all cannabis used in scientific research must be supplied by a single authorised laboratory. The lab produces a single strain, which doesn’t resemble the variety of cannabis strains on the market. While federal law requires scientists to keep their limited stash under lock and key, it’s possible in many states for the public to buy cannabis over the counter. Reefer madness indeed.

Over one million people in the US use medicinal cannabis, while many more self-medicate. Public awareness of the trials from Imperial College and elsewhere may lead more people with mental health problems to experiment with psychedelics – all in a vacuum of strong scientific evidence. This is a dangerous state of affairs: excessive cannabis use is linked to psychosis in teenagers, while the effect of psychedelics can be unpredictable at the best of times, let alone in someone with a mental health condition. Volunteers in the Imperial College trials all received guidance through their trip from a psychotherapist.

Aldous Huxley died from throat cancer in 1963 ten years after his first psychedelic experience. On the day off his death, unable to speak, he wrote a note to his wife asking her to administer him LSD. Huxley passed away peacefully a few hours later. Tentative research into the use of LSD with terminally ill cancer sufferers has shown a significant and sustained reduction in patient anxiety. It’s taken half a century to start turning anecdote from the nascent years of psychedelic research into a solid evidence base. And while incidents of depression and anxiety continue to rise globally, researchers need the freedom to explore novel solutions – including these illegal drugs. The mindset of scientists may be primed, but their setting remains hostile.

About the author

THOMAS LEWTON is a science writer and documentary filmmaker, whose freelance film and photography work has featured on the BBC, VICE and the Guardian.