Psychedelic research is flourishing again, and mainstream Americans may soon feel its impact. MDMA is near the regulatory finish line thanks to MAPS’s recent new drug application submission. And psilocybin is not far behind. 

2023 psychedelic research success means psilocybin could be legal therapeutically in a few short years. The latest studies show that 12 to 25 mg psilocybin doses for depression is sufficient for most patients. In many cases, just one psilocybin dose is enough to create lasting symptom reduction. 

This article examines the latest psychedelic clinical trials featuring psilocybin for depression and outlines key insights into the efficacy of psilocybin-assisted therapy.

01. Study Reveals Long-Term Benefits of 25mg of Psilocybin in Cancer Patients with Depression

Sunstone Therapies, led by Dr. Manish Agrawal, conducted a phase 2 study with Compass Pathways on COMP360 psilocybin therapy in cancer patients with major depressive disorder. COMP360 is Compass Pathway’s proprietary synthetic psilocybin extract.

The open-label, single-center study involved 30 patients with curable and incurable cancer. The methodology included administering a single 25mg* psilocybin dose for depression to patients, along with group and individual psychological support. Researchers evaluated the treatment’s effectiveness at eight weeks and 18 months.

Psychedelic-assisted therapy with a single 25mg psilocybin dose produced remarkable results:

  • More than half of the patients (16 out of 28) remained in remission from their depression 18 months post-psilocybin administration. 
  • Additionally, 18 out of 28 patients (64.2%) demonstrated a sustained clinical response from the baseline to the 18-month follow-up.

Sunstone asserts that this is the longest psilocybin therapy clinical study ever conducted, offering significant insights into psilocybin-assisted therapy for depression among cancer patients. The results were completed in 2021 and published in JAMA Oncology in April 2023.

Compass Pathways is advancing this research through its ongoing Phase 3 clinical program of COMP360 psilocybin therapy in treatment-resistant depression. This program follows the positive results from Compass’s phase 2b psilocybin study, published in the New England Journal of Medicine in November 2022.

(*25 mg of psilocybin extract equals about 2.5 grams of dried mushrooms, assuming each gram contains about 1% psilocybin. Potency rates range from .5 to 2%)

02. Antidepressants Combined with Single Psilocybin Dose Yields Successful Results

Compass Pathways also conducted a Phase 2 exploratory study this year, investigating the use of psilocybin alongside SSRIs (selective serotonin reuptake inhibitors). Nineteen patients followed a fixed-dose design, receiving a 25mg psilocybin dose for depression along with psychological support and daily SSRIs.

The findings revealed that: 

  • 42% of participants showed a clinical response and remission at week three when treated with COMP360 psilocybin in addition to SSRIs for treatment-resistant depression.
  • COMP360 psilocybin treatment was generally well-tolerated, with headache being the most common event. No serious adverse outcomes were reported.

These results suggest SSRIs may not interfere with the therapeutic effect of COMP360 psilocybin. In other words, patients may not need to discontinue SSRI antidepressants to benefit from psilocybin treatment.

03.Single-Dose Psilocybin Treatment for Major Depressive Disorder Shows Remarkable Results

Usona Institute, a non-profit medical research organization, published its long-awaited Phase 2 clinical trial results in August 2023. Usona’s 104-person study tested 25 mg of psilocybin in combination with 20 hours of talk therapy for depression. 

The results were positive, similar to the Institute’s earlier trials.

  • A 25-mg dose of psilocybin with psychological support significantly reduced depressive symptoms in adults with major depressive disorder (MDD), showing rapid and sustained effects.
  • The treatment led to a notable decrease in Montgomery-Asberg Depression Rating Scale (MADRS) scores from baseline to both day 43, indicating a persistent antidepressant effect.
  • Psilocybin was well-tolerated with no serious adverse events.

Usona Institute is currently moving towards a Phase 3 clinical trial with psilocybin.

If Usona and Compass Pathways successfully complete Phase 3 trials, the FDA could approve therapeutic psilocybin use by 2027.

04. Double Psilocybin Dose for Depression Shows 79% No Longer Need Treatment

Earlier this year, biopharmaceutical company Cybin revealed interim results from a Phase 2 trial of synthetic psilocybin (CYB003) for Major Depressive Disorder. The findings showed a single psilocybin dose for depression significantly reduced symptoms, outpacing conventional antidepressants within three weeks. 

Cybin recently shared more data from their study, emphasizing the benefits of a second psilocybin dose for depression. 

  • After a single 12mg dose, participants showed a -14.08 point reduction in MADRS score at three weeks. Twenty percent achieved remission. 
  • After six weeks and two 12 mg psilocybin doses, the depression remission rate impressively increased to 79%. 
  • The study also tested a single 16mg dose for depression, showing similar significant effects. 
  • CYB003’s safety profile was favorable. Some mild and self-limiting adverse events occurred.

These findings suggest CYB003’s potential as an effective treatment for depression, warranting further research in a Phase 3 study.

05. First-Ever Clinical Trial Explores 25mg Psilocybin for Bipolar Disorder

This year, Dr. Scott Aaronson at Sheppard Pratt Hospital led an open-label, nonrandomized, controlled trial study on psilocybin for bipolar II depression. 

This first-of-its-kind research dosed 15 bipolar patients with 25mg of psilocybin. Two weeks prior, all patients discontinued pharmaceutical medication use. The protocol also included therapy sessions before, during, and after the journey. 

The primary outcome was a notable decrease in depression severity, measured by the Montgomery-Åsberg Depression Rating Scale (MADRS). Twelve participants met the clinical response criteria with no significant adverse effects.

After 12 weeks, 11 patients remained in remission with no increase in mania/hypomania or symptoms or suicidality. 

The findings offer new hope for patients with bipolar II disorder, a debilitating,  hard-to-treat condition. 

06. Pioneering Clinical Study Reveals Psilocybin Therapy’s Impact on Anorexia Treatment

Nature Medicine recently published an open-label study on psilocybin assisted therapy for anorexia. Drs. Walter Kaye and Stephanie Knatz Peck from UC San Diego School of Medicine led the initiative.

This pioneering research investigated the effects of a single COMP360 psilocybin session on ten female patients with anorexia. All patients titrated off SSRIs and engaged in preparatory sessions leading to the journey. 

On the dosing day, patients received 25mg of psilocybin with psychological support for eight hours. They received follow-up assessments the next day, one week later, one month later, and at three-month intervals.

The results showed significant reductions in eating disorder symptoms with a single 25mg psilocybin dose.

  • 40% of participants showed significant reductions in eating disorder psychopathology at three months.
  • Statistically significant reductions in shape and weight concerns were observed.
  • Five participants had an increase in BMI, although changes were not statistically significant.
  • Treatment was well-tolerated, with mild and transient adverse events.

Participants also regard the psilocybin experience as meaningful, with positive shifts in personal identity and quality of life. 

07.  Largest-Ever Survey of Naturalistic Psilocybin Use Finds Abundance of Benefits

This year, Frontiers in Psychiatry published comprehensive survey results revealing the impact of psilocybin use in natural, non-clinical settings. Johns Hopkins researchers, led by Matthew Johnson, gathered 24 months of data from 2,833 people using psilocybin for self-discovery. 

Participants were primarily educated white men from the U.S. who consumed an average of 3.1 grams of dried mushrooms. Respondents completed questionnaires before and after psilocybin use. 

Survey analysis found that participants experienced lasting improvements in mental health, cognitive flexibility, and well-being. Specifically, journeyers reported enduring reductions in depression, anxiety, and alcohol misuse. Cognitive flexibility and emotional regulation also improved. Participants even felt more spiritual and extraverted. 

However, a minority reported persisting adverse effects following their psilocybin journey. Specifically, 11 percent experienced mood fluctuations and depressive symptoms two to four weeks afterward. Seven percent reported these symptoms two to three months later.

The findings emphasize psychedelics’ nuanced effects and variability based on factors like dosage, setting, medical history, and emotional state.

08. Study Compares 25mg Psilocybin Dose and Escitalopram for Major Depressive Disorder

In a groundbreaking study published in Cambridge University Press, researchers from Johns Hopkins University compared psilocybin-assisted therapy with escitalopram treatment (a common antidepressant) for major depressive disorder. 

Over six weeks, the trial observed 59 patients’ changes in personality traits such as neuroticism, introversion, and impulsivity. 

The psilocybin therapy (PT) group received a 25mg COMP360 synthetic psilocybin dose. The escitalopram cohort received 1 mg of psilocybin, followed by escalating doses of escitalopram. Both groups underwent a second session three weeks later. The PT group received another 25mg psilocybin dose for depression. The escitalopram unit took 1 mg of psilocybin and an increased daily escitalopram dose of 20 mg. All patients received psychological support and assessments at week six and a six-month survey.

The results showed both psilocybin assisted therapy and escitalopram led to positive personality changes. 

  • Psilocybin therapy resulted in decreased neuroticism, introversion, disagreeableness, and impulsivity and increased openness and absorption.
  • Escitalopram therapy also led to reductions in neuroticism, impulsivity, and disagreeableness and an increase in openness.
  • Psilocybin was particularly effective in reducing non-planning impulsivity and disagreeableness, associated with depression and its dysfunctions.
  • Personality changes, especially in neuroticism and openness, were maintained for up to six months post-intervention.

Researchers had hoped to see a wider gap between psilocybin and antidepressant outcomes. 

Still, the findings showed that psilocybin therapy could be a viable alternative to SSRIs for depression, with advantages such as avoiding chronic drug administration and related side effects.

In a recent study published in the Journal of Psychoactive Drugs, researchers established a connection between psilocybin and reduced distress among people with childhood adversity.

Those immersed in the psychological field might find this link obvious. However, these findings reinforce the notion that childhood trauma creates various mental health issues later on in life. 

The study examined how psilocybin relates to psychological distress, with a focus on Adverse Childhood Experiences (ACEs) like abuse, neglect, and exposure to violence. Researchers collected data on participants’ demographics and psilocybin usage history, including consumption frequency, dosage, and intent.

The research uncovered that recent psilocybin use, within the past three months, correlated with lower psychological distress, mainly benefiting those with a history of adverse childhood incidents. Additionally, explorers expressed positive opinions about psilocybin’s benefits and safety, often employing it as a self-help tool for addressing mental health challenges.

10. Analysis Reveals Psilocybin Dose is a Major Factor in Influencing Journey Intensity 

King’s College London recently conducted a pivotal psilocybin therapy study to identify factors that intensify mystical and challenging experiences during psilocybin sessions. The findings are crucial for fine-tuning psychedelic medicine’s effectiveness

Here’s how it worked: King’s College researchers conducted an intricate post hoc Phase 1 clinical trial analysis of 89 healthy volunteers who received either a placebo, 10 mg, or 25 mg of psilocybin for depression. Utilizing statistical analysis, the researchers assessed how different dosages influenced the participants’ experiences. Beyond dosage effects, the study scrutinized the influence of personality traits, affect, and individual participant outcomes.

Findings indicated that dosage was the most crucial factor.

  • Dose: Higher psilocybin doses led to more intense mystical and challenging experiences.
  • Age: Older participants reported less intense challenging experiences than younger respondents.
  • Personality Traits: Neuroticism positively correlated with the intensity of challenging experiences. But only at higher psilocybin doses.
  • Emotional State: Neither positive nor negative emotional states significantly correlated with the intensity of mystical or challenging experiences.

While exploratory, this study signals a step forward in advancing psilocybin therapy and predicting outcomes based on dosage, age, personality, and emotions. This information empowers practitioners and patients with knowledge to prepare for safe and effective journeys. 


  1. Agrawal M, Emanuel E, Richards B, Richards W, Roddy K, Thambi P. Assessment of Psilocybin Therapy for Patients With Cancer and Major Depression Disorder. JAMA Oncol. 2023;9(6):864–866. doi:10.1001/jamaoncol.2023.0351
  2. Compass Pathways Announces Publication of Positive Data from Treatment-Resistant Depression Phase 2 Clinical Trial of COMP360 Psilocybin Alongside Antidepressants in Nature Journal Neuropsychopharmacology. Compass Pathways, Publication Date: [July 17, 2023].
  3. Raison CL, Sanacora G, Woolley J, et al. Single-Dose Psilocybin Treatment for Major Depressive Disorder: A Randomized Clinical Trial. JAMA. 2023;330(9):843–853. doi:10.1001/jama.2023.14530
  4. Cybin Announces Unprecedented Positive Phase 2 Interim Data for CYB003 in Major Depressive Disorder: Meeting Primary Efficacy Endpoint with Rapid and Significant Improvements in Depression Symptoms After Single Dose.” Business Wire,
  5. Aaronson ST, van der Vaart A, Miller T, et al. Single-Dose Synthetic Psilocybin With Psychotherapy for Treatment-Resistant Bipolar Type II Major Depressive Episodes: A Nonrandomized Controlled Trial. JAMA Psychiatry. Published online December 06, 2023. doi:10.1001/jamapsychiatry.2023.4685
  6. Peck, S.K., Shao, S., Gruen, T. et al. Psilocybin therapy for females with anorexia nervosa: a phase 1, open-label feasibility study. Nat Med 29, 1947–1953 (2023).
  7. Nayak, S. M., Jackson, H., Sepeda, N. D., Mathai, D. S., So, S., Yaffe, A., Zaki, H., Brasher, T. J., Lowe, M. X., Jolly, D. R. P., Barrett, F. S., Griffiths, R. R., Strickland, J. C., Johnson, M. W., Jackson, H., & Garcia-Romeu, A. (2023). Naturalistic psilocybin use is associated with persisting improvements in mental health and wellbeing: results from a prospective, longitudinal survey. Frontiers in Psychiatry, 14, Article 1199642.
  8. Weiss B, Ginige I, Shannon L, et al. Personality change in a trial of psilocybin therapy v. escitalopram treatment for depression. Psychological Medicine. 2023:1-15. doi:10.1017/S0033291723001514
  9. Kiffer G. Card , Ashmita Grewal , Kalysha Closson , Gina Martin , Laura Baracaldo , Sandra Allison , Daniel J. Kruger & Zach Walsh (2023) Therapeutic Potential of Psilocybin for Treating Psychological Distress among Survivors of Adverse Childhood Experiences: Evidence on Acceptability and Potential Efficacy of Psilocybin Use, Journal of Psychoactive Drugs, DOI: 10.1080/02791072.2023.2268640
  10. Ko K, Carter B, Cleare AJ, Rucker JJ. Predicting the Intensity of Psychedelic-Induced Mystical and Challenging Experience in a Healthy Population: An Exploratory Post-Hoc Analysis. Neuropsychiatr Dis Treat. 2023;19:2105-2113

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