25 Oct 2018

Current research supporting psilocybin therapy

by Psillow

In this article, Johns Hopkins researchers, Matthew Johnson and Roland Griffiths, provide a review of the current research literature supporting the potential therapeutic effects of psilocybin for a number of conditions. In the article, they specifically highlight findings from such research on the following health concerns: cancer-related psychiatric disorder; depression; addiction; obsessive compulsive disorder (OCD); and cluster headaches.

  • One study with 12 advanced stage cancer patients found decreases in depression and anxiety two weeks after taking a moderate dose (0.2 mg/kg) of psilocybin compared to placebo conditions, with effects persisting at 3 and 6 months follow-up (for anxiety and depression, respectively).
  • A similar study examined the effects of a moderate dose (0.3 mg/kg) of psilocybin in 29 cancer patients with severe anxiety and found favourable clinical effects, including reductions in anxiety and depression and increased quality of life, even 6 months after the study.
  • Another study compared the effects of very low doses (0.01-0.04 mg/kg) of psilocybin with high doses (0.3-0.4 mg/kg) of psilocybin on reducing anxiety in 51 patients with life-threatening cancer. The researchers found not only sustained effects at 6 months follow-up, but also improved outcomes in those who received high doses relative to low doses of psilocybin.
  • Studies have also found promising effects of psilocybin reducing psychiatric distress in patients with non-terminal cancer and life-threatening diseases other than cancer.


  • One study among 12 patients with treatment-resistant depression found that taking 10 mg at an initial session and 25 mg in a second session one week later resulted in significantly decreased depression scores 1 week and 3 months after their treatments.


  • Studies exploring the effects of psilocybin on treating various addictions are been under-resourced and currently still in their infancy. Nonetheless, Johnson and Griffiths speculate that these studies are worth pursuing based on preliminary research suggesting positive effects of LSD treatments among people with alcoholism.
  • One study examined the effects of moderate doses (0.3 mg/kg) of psilocybin among 15 patients with treatment-resistant tobacco/nicotine dependence, along with cognitive behavioural therapy (CBT) sessions. The study found that 80% of patients who received both treatments were abstinent from smoking at 6 months follow up, and 75% of patients remained abstinent 2.5 years later.
  • Johnson and Griffiths conducted an online survey, which identified 358 individuals who reported to have quit or reduced their smoking after taking a psychedelic, in addition to reporting fewer emotion-related withdrawal symptoms (e.g., depression, cravings) compared to previous attempts to quit smoking prior to taking a psychedelic. These preliminary studies should not be taken as conclusive evidence, but their findings do justify larger studies on the effects of psilocybin as a potential smoking cession intervention.
  • In a study of psilocybin treatment (0.3-0.4 mg/kg) in conjunction with four therapy sessions among 10 alcohol-dependent patients, the researchers found lower self-reported levels of drinking up to 8 months after the program. Based on these findings, a larger randomized controlled trial of psilocybin for the treatment of alcohol dependence is currently underway.


  • A study of 9 patients with OCD who were given four small doses (between 0.03-0.3 mg/kg) of psilocybin over four weeks found substantial reductions in symptoms one week after treatment. One of the nine patients showed long-term improvements at 6 months follow-up. While these findings appear promising, the researchers note that the results could be explained by a placebo or expectancy effect displayed among the study participants.

Cluster Headaches

  • A case study of 53 cluster headache patients who self-medicated with psilocybin mushrooms and LSD suggested that these substances may have some utility in reducing and preventing cluster headaches; a condition notorious for being severely painful and debilitating, as well as difficult to treat.

The authors note a number of caveats in the above research. First, due to the nature of psilocybin research, many of the studies summarized in the article are pilot studies with small numbers of participants. Larger studies with different populations of patients should be conducted before concrete conclusions about psilocybin’s safety and effectiveness as a treatment method can be drawn. Second, all of the above studies used psilocybin as a treatment method not alone, but in conjunction with other forms of treatment such as psychotherapy or CBT. Extreme caution was taken to ensure that participants were appropriately screened and prepared for the study in order to reduce the possibility of physical or psychological harm. For example, taking psilocybin can have extremely negative effects for individuals with psychotic disorders, so the studies described above each exercised caution in ensuring that nobody with an existing psychotic disorder (or family history of a psychotic disorder) participated. Patients in the above studies were also continuously monitored during the above treatments, and given the opportunity to talk through their experiences with research staff members in order to facilitate positive experiences of change and growth while also mitigating potentially adverse reactions.

Finally, although the researchers of the above studies did not report any negative effects due to psilocybin use under controlled settings, Johnson and Griffiths caution that psilocybin should only administered in safe, comfortable and responsibly monitored settings because of their perception-altering effects. As well, they cautioned those with psychotic disorders and cardiovascular problems should not use psilocybin, as the substance can lead to extended psychiatric reactions and increased blood pressure, respectively, in these populations.

Even though the studies highlighted in this article have shown promising results of psilocybin for alleviating the symptoms of these negative – and often difficult-to-treat – health conditions, funding for such research remains sparse and is generally not supported (and even actively blocked) by government institutions. In light of the current evidence, the authors call for a greater flow of resources to support larger rigorous investigations into the safety and effects of psilocybin as a therapeutic treatment option.

Summary of: Johnson MW, Griffiths RR. Potential therapeutic effects of psilocybin. Neurotherapeutics. 2017 Jul 1;14(3):734-40.

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