In November, Colorado became the second US state after Oregon to legalise the medical use of psilocybin, the psychedelic compound found in magic mushrooms. The measure legalising the drug takes effect in 2024 and also establishes a process to potentially legalise other plant- and fungi-based psychedelic drugs for therapeutic use in 2026. It also decriminalises the recreational use of all these drugs except for peyote.
This law is part of a growing push to make psychedelic drugs more accessible. Since 2019, have considered bills that would increase access to psychedelic drugs or psychedelic drug research. The trend is largely spurred by research suggesting that these drugs may help treat conditions like depression, post-traumatic stress disorder (PTSD) and addiction. While promising, these findings aren鈥檛 yet conclusive enough to show that psychedelic drugs should be readily used for therapeutic purposes, says at Johns Hopkins University in Maryland.
The issue is that most studies on psychedelic drugs only include a small number of participants and almost all lack an effective control as people can generally discern when they are having a psychedelic experience, says Yaden. There are also no comparable drugs that are both safe and effective as a control, he says. This leaves many questions about the efficacy of psychedelic drugs and the best way to administer them.
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Another issue is a lack of funding. In the past decade, the US government has only spent $140 million on psychedelic drug research compared with $2.2 billion on cannabis and $8.1 billion on tobacco, according to research presented at a November meeting of the Society for Neuroscience by , a neuroscientist formerly at the National Institute on Drug Abuse in Maryland. Meanwhile, the Australian government spent to fund psychoactive drug research this year, though this included non-psychedelic substances such as cannabidiol (CBD). In the UK, funding for psychedelic drug research is also hampered .
Of the little evidence available, findings are strongest for using psilocybin to treat depression. Research suggests the drug may be as effective at treating the condition as selective serotonin reuptake inhibitors (SSRIs), the most widely used type of antidepressant. A study published last year of 59 people found in changes in depression scores between those who were given two 25-milligram doses of psilocybin three weeks apart and those given a daily SSRI for six weeks.
鈥淲e have to be careful not to overhype the therapeutic benefits,鈥� says Boehm. 鈥淭his isn鈥檛 a miracle cure, and [it鈥檚] not going to work for everybody.鈥�
In fact, the largest psilocybin trial to date included 233 people with treatment-resistant depression and showed lower efficacy for the drug than in previous trials. Nearly of those given a 25-milligram dose of psilocybin, 9 per cent given a 10-milligram dose and 8 per cent given a 1-milligram dose were in remission three weeks after treatment, whereas a previous trial showed improvement in 70 per cent of participants. The effect also diminished over time: only 20 per cent of those in the 25-milligram group saw a lasting improvement in depression scores 12 weeks later.
鈥淚 think public perceptions have really outpaced what the research has actually provided,鈥� says Yaden. 鈥淚f you鈥檝e been subjected to the massive over-the-top hype suggesting that psychedelics are the new cure for mental disorders, then [these results] will be very disappointing.鈥� Evidence for the drug鈥檚 efficacy in treating other conditions, such as PTSD and addiction, is even less conclusive, though further research is currently underway.
鈥淚 think that in the pretty near future, we鈥檙e going to have a much better sense of the risk-benefit profile of psychedelics [for medicinal purposes],鈥� says Yaden. 鈥淪o, for those reasons, my sense is let鈥檚 wait to see the data.鈥�
On the other hand, Colorado鈥檚 measure is a step towards reversing restrictive drug policies that the US government enacted around 1970, which made it difficult to procure and fund psychedelic drug research, effectively shutting down the field, says Yaden. As nearly 40 US states have legalised medical marijuana, research on its effects has flourished: since 2015, federal funding on the therapeutic potential of cannabis has . It鈥檚 possible that legalisation, and the wider availability that comes with it, could help fund psychedelic research in the same way, says Boehm.
