Image by: Pavel Tchelitchew. Spiral Head. 1950.

WHAT'S NEW IN PSILOCYBIN RESEARCH?

Written by: Dr. Lindsay Mackay, MD, CCFP

There have been exciting developments in the world of psilocybin research. The number of studies published are growing exponentially each year and later stage research is well underway. Notably, the first randomized placebo-controlled study using psilocybin-assisted therapy to treat an addiction published very positive findings – opening the door for further research using psilocybin to treat problematic substance use and addictions.

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A FEW QUICK NOTES ON RESEARCH TERMS:

• Randomized refers to the process where study participants are assigned to a treatment group or placebo at random, with an equal chance at being in each group. This helps to make sure that differences between treatment and placebo groups are due to the treatment rather than differences in group characteristics.
• Placebo controlled means the treatment (psilocybin in the below studies) is compared to a sham or fake treatment to help determine if any group differences are really due to the treatment or drug rather than some other factor.
• Double blind refers to the technique where both the study participants and researchers are not aware if they are receiving placebo or treatment. This helps to reduce bias that may occur. For example, if a participant is expecting to feel better from a treatment, they may feel better just because they expect to rather than a true benefit from treatment.

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Percentage of Heavy Drinking Days Following Psilocybin-Assisted Psychotherapy vs Placebo in the Treatment of Adult Patients With Alcohol Use Disorder: A Randomized Clinical Trial

Study Design: 95 people with alcohol use disorder received either two psilocybin or placebo-assisted therapy sessions. The study took place over 12 weeks including preparation and integration therapy sessions. Heavy drinking days were compared before and after treatment between the two groups. 

Findings: Psilocybin significantly reduced heavy drinking days and average daily alcohol intake compared to the active placebo group. Nearly half of the people who were given psilocybin stopped drinking altogether compared to less than a quarter in the placebo group. No serious adverse events occurred.

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Single-Dose Psilocybin for a Treatment-Resistant Episode of Major Depression

Study design: Approximately 200 people with treatment resistant depression received one treatment of either 25 mg, 10 mg or 1 mg of psilocybin. Depression severity before and after treatment was compared between the groups. 

Findings: Depression severity was significantly reduced in the 25 mg group compared to the 10 mg and 1 mg groups where no difference was found. 

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Microdosing with psilocybin mushrooms: a double-blind placebo-controlled study

Study Design: 34 healthy blinded participants took a half-gram of dried psilocybin mushrooms or placebo. Subjective experience, behavior, perception, thinking and brain activity were compared between the groups.

‍Findings: No difference was found between the two groups; however, it is difficult to measure any true diffidence in a lab setting for a single day of microdosing. Additionally, it is challenging to measure complex traits like creativity using rudimentary tests that cannot capture the expression of these traits in the real world. Bottom line – we need longer term larger studies to assess the potential benefits and risks of microdosing mushrooms.

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Acute Effects of Psilocybin After Escitalopram or Placebo Pretreatment in a Randomized, Double-Blind, Placebo-Controlled, Crossover Study in Healthy Subjects

Study Design: Health participants were given either placebo or escitalopram (a common anti-depressant and anti-anxiety medication) for two weeks before receiving psilocybin. 

Findings: Participants who received the anti-depressant had no change to the positive mood effects of psilocybin. Interestingly, the antidepressant group had less negative side effects including lower anxiety and less of an increase in blood pressure and heart rate during the psilocybin treatment. Escitalopram did not change the metabolism of psilocybin. This study supports that escitalopram and psilocybin could be safely taken together.

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Efficacy and safety of psilocybin-assisted treatment for major depressive disorder: Prospective 12-month follow-up

Study design: 27 participants with moderate to severe depression received two sessions of psilocybin-assisted therapy. Participants were followed for one year after completing treatment. 

Findings: One year after completing treatment, 75% of participants had a 50% or greater improvement in depression symptoms and 58% were in remission from depression.  This is a remarkable improvement sustained for one year - compared to currently available antidepressants, which only meaningfully improve symptoms for roughly 30% of people. 

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Dr. Lindsay Mackay, MD, CCFP

Dr. Lindsay Mackay MD, CCFP, Department of Family Medicine, UBC is a clinician-scientist and addiction specialist. She is a primary care and addiction medicine physician with PHS Community Services Society and Vancouver Coastal Health in Vancouver’s Downtown Eastside. She currently provides ketamine, psilocybin, and MDMA-assisted therapy for people with mental health concerns.

Lindsay is a graduate of the British Columbia Centre on Substance Use, NIDA-funded International Collaborative Addiction Medicine Research Fellowship. She is experienced in the exploration of psychedelics as novel therapies and is currently involved with clinical trials evaluating psychedelic therapy for treating mental health conditions and problematic substance use.

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*DISCLAIMER: The materials presented by this web site, www.yawntogether.com, are for informational and harm reduction purposes only and are not offered as medical or legal advice as to any particular matter in any particular jurisdiction. No reader should act on the basis of these materials without seeking appropriate professional advice as to the particular facts and applicable law involved.

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