The renaissance of psychedelic research continues to gather pace, with an ever-growing number of studies amassing that explore the therapeutic potential of psychedelics. Of these, psilocybin has been taking the limelight. And for good reason. It appears to show great promise as a treatment for several psychiatric conditions, while also having the potential to lead to “the betterment of well people” as Bob Jesse put it, one of the people behind the sparking of the modern psychedelic research renaissance.

Amid a flurry of studies in recent years, a number highlight psilocybin’s multifaceted potential. Some say that this increase in the last decade was sparked by the pivotal study called ‘Psilocybin can occasion mystical-type experiences’ in 2006 led by Roland Griffiths and a team at Johns Hopkins. The study employed a rigorous design and looked at the effects of high doses of psilocybin on spiritually interested people who had never taken a psychedelic before. Psilocybin reliably occasioned mystical experiences very similar to those reported occurring spontaneously by mystics going back through the centuries, with the majority of participants describing these experiences as among the most personally meaningful and spiritually significant of their lives.

The mystical experiences that high doses of psilocybin can reliably occasion are deeply tied to the enduring benefits that people report, across studies. Mystical experiences are characterised by a number of traits, including deeply felt positive mood, transcendence of time and space, and a profound sense of unity, infusing life with a renewed sense of purpose and meaning.

Take a look at our top ten scientific papers of the last decade, selected because they provide an expansive overview of modern research on psilocybin, highlighting its multifaceted potential, both as a psychiatric treatment, and as a catalyst that can enhance the lives of healthy people in a number of ways.

1. Addiction to smoking

'Long-term follow-up of psilocybin-facilitated smoking cessation' - Johnson, M., Garcia-Romeu, A. & Griffiths, R. (2017)

Following the results of a few pioneering studies, psilocybin shows great promise in addiction treatment. Johnson et al’s 2017 study looking at tobacco addiction yielded impressive results that far surpass any mainstream treatment options. At 12 months post-experience, 67% of participants were smoking free, and 86.7% rated the experience as among the most meaningful of their lives. Interestingly, some participants reported that their enduring smoking abstinence was among the least interesting outcomes of their experience.

2. Addiction to alcohol

‘Psilocybin-assisted treatment for alcohol dependence: A proof-of-concept study’ - Bogenshutz, M., Forcehimes, A., Pommy, J., Wilcox, C., Barbosa, P. & Strassman R. (2015)

Psilocybin has also been examined as a treatment for alcoholism. One study found it to be highly effective, with enduring abstinence tied to the intensity of effects experienced. While the results of these latter two studies appear impressive, it is worth noting that they are both small proof-of-concept studies with small sample sizes and no placebo control group. In both cases, more rigorous Phase II studies are currently ongoing to better evaluate psilocybin’s addiction breaking potential.

3. Psilocybin treating depression

'Psilocybin with psychological support for treatment-resistant depression: six-month follow-up' - Carhart-Harris, R., Bolstridge, M., Day, C., Rucker, J., Watts, R., Erritzoe, D., Kaelen, M., Giribaldi, B., Bloomfield, M., Pilling, S., Rickard, J., Forbes, B., Feilding, A., Taylor, D., Curran, H. & Nutt, D. (2018)

Psilocybin appears to show great promise in the treatment of depression. A follow-up study of the first pioneering trial exploring this reported that at six months post-session, 31% of participants with treatment-resistant depression reported enduring antidepressant effects, with reductions in depression again tied the quality of the psychedelic experience. Numerous more extensive and rigorous studies are currently ongoing around the world.

4. Bad trips or challenging experiences?

‘Survey study of challenging experiences after ingesting psilocybin mushrooms: Acute and enduring positive and negative consequences’ - Carbornaro, T., Bradstreet, M., Barrett, F., MacLean, K., Jesse, R., Johnson, M. & Griffiths, R. (2016)

While numerous assessments have found mushrooms to be the safest of all substances, at times they can yield highly challenging experiences. Carbonaro et al’s study found that 39% of people rated their worst experience as among the five most challenging experiences of their lifetime. However, 84% of people endorsed the experience as having benefits. While psychedelic experiences are sometimes characterised as being ‘bad’ or ‘good’ trips, this shows that labelling such experiences in such a binary fashion is a limited way of categorising them.

5. Therapeutic mechanisms

'Patients’ Accounts of Increased “Connectedness” and “Acceptance” After Psilocybin for Treatment-Resistant Depression' - Watts, R., Day, C., Krzanowski, J., Nutt, D. & Carhart-Harris, R. (2017)

A six-month follow-up study, which assessed participants from the latter psilocybin-depression study, revealed two of the critical therapeutic aspects of the psilocybin experience. These were a shift from a sense of disconnection (from self, others and the world) to connection, and from a state of emotional avoidance to acceptance. This was in contrast to more conventional treatments participants had tried previously, which tended to exacerbate disconnection and avoidance, showing psilocybin works through novel means.

6. Psilocybin and existential anxiety

'Long-term follow-up of psilocybin-assisted psychotherapy for psychiatric and existential distress in patients with life-threatening cancer.' - Agin-Liebes, G., Malone, T., Yalch, M., Mennenga, S., Ponte, K., Guss, J., Bossis, A., Grigsby, J., Fischer, S. & Ross, S, (2020)

Three separate studies, at UCLA, Johns Hopkins and NYU, explored the potential of psilocybin to treat existential anxiety in terminally ill cancer patients. They built up the strongest evidence base by far for any indication against which psilocybin has yet been tested. Not only was a single psilocybin experience found to be highly effective in the majority of participants, the benefits also appear to be highly enduring. A follow-up study of surviving NYU participants conducted four and a half years later reported sustained antidepressant and anti-anxiety effects, with participants considering their experiences as among the most deeply profound of their lives.

7. Effects of psilocybin on creative thinking, empathy and wellbeing

‘Sub-Acute Effects of Psilocybin on Empathy, Creative Thinking, and Subjective Well-Being’ - Mason, N., Mischler, E., Uthaug, M. & Kuypers, K. (2019)

Beyond it being a potentially paradigm changing treatment for a number of hard to treat mental health conditions, psilocybin also holds value for otherwise healthy people. This study used a retreat setting to assess the effects of psilocybin on creative (convergent and divergent) thinking, empathy and life satisfaction the morning and one week after psilocybin sessions. Even at lower doses, psilocybin was still capable of enhancing convergent thinking, empathy and wellbeing up to seven days later.

8. Increasing connection to nature

'Increased nature relatedness and decreased authoritarian political views after psilocybin for treatment-resistant depression' - Lyons, T. & Carhart-Harris, R, (2018)

Another study investigating how people’s values change after psilocybin experiences found that people were less prone to authoritarian views and reported feeling more connected to nature up to a year later. This is an important finding, as one’s connection to nature is strongly associated with a broad range of traits associated with psychological well-being, it enhances some of the benefits obtained from spending time in nature, and strongly predicts pro-environmental behaviour. Could this mean that taking psychedelics could lead to a stronger desire to protect nature? Read our article on connection to nature to find out more.

9. Lasting positive effects of a mystical experience and integration

'Psilocybin-occasioned mystical-type experience in combination with meditation and other spiritual practices produces enduring positive changes in psychological functioning and in trait measures of prosocial attitudes and behaviors' - Griffiths, R., Johnson, M., Richards, W., Richards, B., Jesse, R., MacLean, K., Barrett, F., Cosimano, M. & Klinedinst, M. (2018)

A number of studies have suggested psychedelics yield more benefits when used alongside existing practices. This study found that the mystical experiences from psilocybin, in combination with spiritual practices such as meditation and journaling, produced enduring shifts in prosocial values and behaviour, while promoting healthy psychological functioning.

10. Enduring positive effects in healthy people

‘Acute, subacute and long-term subjective effects of psilocybin in healthy humans: a pooled analysis of experimental studies’ - Studerus, E., Kometer, M., Hasler, F. & Vollenweider, F. (2011)

This paper pooled data from 8 studies where a total of 110 healthy volunteers were administered psilocybin between 1-4 times, and it looked at the acute, short-term and long-term subjective effects psilocybin produced. Psilocybin was well tolerated and considered pleasurable, enriching and non-threatening by participants. Negative reactions were very rare and could be managed by interpersonal support, and there were no prolonged negative reactions reported. A number of enduring benefits were reported 8-16 months later, including a greater appreciation of art and music, and changes in people’s relationship to nature.

Looking ahead, the future seems bright for psychedelic research. The initial proof-of-concept studies on psilocybin have shown that it holds great promise in the treatment of a number of otherwise hard to treat conditions. A number of more rigorous Phase II studies are now ongoing, to investigate this potential in more depth. At the same time, more pioneering trials are also planned, to investigate whether psilocybin therapy may hold promise for a range of other mental health conditions. While research on the clinical application of psilocybin continues to advance, research on the potential of psilocybin to benefit healthy adults is also moving forward. In time we will gain an ever clearer picture of the multitude of ways in which this special molecule can benefit human lives.

If you would like to find out more about research on psilocybin, including research that Synthesis is involved in, please click here. Synthesis has support from several leading psychedelic researchers on its advisory board. This helps ensure that Synthesis facilitates truffle retreats to the very highest standards possible, in order to maximise the potential benefits one can hope to obtain.