Archeologic findings show that psilocybin-containing mushrooms may have been used for over 7,000 years (4).  Prehistoric and Pre-Columbian art, including sculptures and depictions of psilocybin mushrooms, and humans consuming these mushrooms, has been  found in prehistoric Spanish caves (5), and in the ancient Mayan and Aztec cultures of Mesoamerica (5).  These works suggest that magic mushrooms were used in religious ceremonies, and played an important cultural role.

After the Spanish conquest of Mexico, missionaries set out to eradicate the use of psychoactive plants and mushrooms because they believed the mushrooms allowed the Aztecs to communicate with “devils”.  To avoid persecution, the traditional use of teonanácatl (divine flesh) was pushed underground, and the traditional mushrooms practices were preserved (6).

In the 1950s the Wassons, Valentina and Gordon, were the first Westerns to participate in traditional psilocybin mushroom ceremonies in Mexico.  They publicized their experience in Time magazine (7), which led to an explosion of popularity that drove the 1960s counter culture movement, and subsequent classification of psilocybin as a Schedule I drug in the US (deemed to have no medicinal value, high potential for abuse, and lack of safety data) in 1971.

Today, psilocybin is still illegal in most countries apart from a few exceptions (8).  Despite the illegality of psilocybin, they are one of the most consumed psychedelics among people under 34 in the U.S (9). In 2019, two U.S. cities, Denver and Oakland, became the first to pass a ballot decriminalizing adult use and possession of psilocybin mushrooms (10). In light of recent therapeutic findings, psilocybin has been reclassified from a banned substance to an FDA-approved medicine.  Promising psilocybin research has also led to founding of The Center for Psychedelic and Consciousness Research at Johns Hopkins University.

Research suggests psilocybin with accompanying psychological support and when taken with a clear intention can be a safe and  effective treatment for a number of psychological conditions including: depression, including treatment-resistant depression, and anxiety in people with a terminal illness,  alcohol and nicotine addiction, obsessive-compulsive disorder (OCD), and cluster headaches.  Additionally, when administered in a controlled setting, psilocybin has been shown to improve quality of life and improve overall feelings of wellbeing and spiritual connection/mystical-type experiences. 

Psilocybin has been shown to produce significant and sustained reductions in levels of depression and anxiety in patients who experience cancer-related/end-of-life psychological distress. Psilocybin can significantly and sustainably reduce symptoms of severe depression in people who suffer from depressive disorders. In addition, Psilocybin has also been shown to reduce thoughts of suicide and self-harm. 

• The U.S. Food and Drug Administration (FDA) has given a psilocybin-based drug “breakthrough therapy” status to be tested byCOMPASS Pathways. One clinical trial is underway by COMPASS Pathways to test the safety and efficacy of psilocybin on participants with treatment-resistant depression (11). A total of 216 participants will be administered low, medium, and high doses of psilocybin. The estimated completion date is June 2020.

• A 2011 pilot study was conducted to test whether psilocybin is effective for treating depressive and anxious symptoms in terminally ill cancer patients (12). The results showed that patients showed significant improvements after the psilocybin treatment for up to six months after administration.

• In a study published in 2016, researchers examined how psilocybin with psychological support could potentially help with treatment-resistant depression (13). 12 patients were given two doses of psilocybin in conjunction with professional therapy. After one week from the second dose, depression scores were lower in almost all participants. After three months, five of the twelve patients were still free of depressive symptoms. Four other patients were still experiencing depressive symptoms but reported that their depression had gone from a rating of ‘severe’ to ‘mild’ or ‘moderate’.

• This study suggests suggest that lifetime use of psilocybin but no other classic psychedelic may be especially protective with regard to psychological distress and suicidality. Psilocybin in particular may thus hold promise as an innovative mental health intervention and suicide prophylaxis (14).

Promising results of psychedelic use for addiction were discovered in the 1950s and 1960s (15), and current studies are building upon these findings. Several clinical trials have shown that psilocybin, when used in conjunction with therapy, may be more effective than conventional methods of treating a number of substance abuse disorders, including alcohol and tobacco. A study on cocaine addiction disorder is currently underway.

• In a 2015 study, ten volunteers were reported to show significant reductions in alcohol consumption and increased abstinence after psilocybin was administered in the context of a therapy program (16).

• In one recent clinical trial, two to three psilocybin treatments were used together with a cognitive behavioral therapy (CBT) program to help people quit smoking. The results showed that after six months, 80% of the participants had successfully quit smoking (17). This is far higher than conventional methods used for smoking cessation such as nicotine gums and patches which only have an average success rate of around 35%.
  
  
• In a 2014 study smoking cessation outcomes were significantly correlated with measures of mystical experience, as well as ratings of personal meaning and spiritual significance of psilocybin sessions (18).

• In a pilot study to investigate the effectiveness of psilocybin-assisted treatment for smoking cessation participants reported gaining vivid insights into self-identity and reasons for smoking from their psilocybin sessions. Preparatory counselling, strong rapport with the study team, and a sense of momentum once engaged in the study treatment were perceived as vital additional factors in achieving abstinence. In addition, participants reported a range of persisting positive changes beyond smoking cessation, including increased aesthetic appreciation, altruism, and pro-social behavior (19).

• A recent open-label pilot study found that two to three moderate to high doses (20 and 30 mg/70 kg) of  psilocybin, in combination with cognitive behavioral therapy (CBT) for smoking cessation, resulted in substantially higher 6-month smoking abstinence rates than are typically observed with other medications or CBT alone (20).

• A team of researchers affiliated with Boston University and Harvard Medical School published a study reporting that opioid users had a lower chance of becoming dependent on opioids if they had experience with psychedelic drugs (21).

• A clinical trial directed by researchers at the University of Alabama at Birmingham is currently underway exploring the effectiveness of psilocybin for cocaine addiction in 40 participants (22). Cocaine addiction, unlike nicotine and alcohol addiction, has no pharmacological treatment to date. It will be interesting to see how effective psilocybin is, given it is more effective than conventional methods for alcohol and smoking cessation. This trial is estimated to be completed in mid-2020.

There is some evidence that psilocybin can help with cluster headaches, although more clinical trials are needed to further investigate this effect.

• No randomized controlled trials exist proving the efficacy of psilocybin for the treatment of cluster headaches, but many anecdotes support psilocybin being effective. In the mid-2000s, medical professionals recognized these anecdotal claims after patients reported decreased cluster headache symptoms following psychedelic use (23).
  
  
• In one survey, psilocybin was shown to potentially be more effective than current conventional treatments for cluster headaches (24). Almost 50% of participants reported experiencing complete relief.

Limited research suggests psilocybin mushrooms could be used safely to help decrease the symptoms of OCD.

• In one study researchers examined nine patients to explore the efficacy of psilocybin for OCD (25). Patients who didn’t respond to conventional serotonin reuptake inhibitor (SSRI) drug therapy experienced a reduction of OCD symptoms ranging from 23-100% with a psilocybin treatment.

It is critical to carefully consider your mindset, intentions, and safety and comfort of the environment before engaging in any activity that will expand your awareness, as this will profoundly affect the experience.

The most likely risk associated with psilocybin mushrooms is the “bad trip” (anxiety, fear, paranoia).  Though even in unprepared, and unsupervised conditions violent or self-destructive behavior is very rare, it is still possible (26).

Psychedelics, like psilocybin mushrooms, can provoke the onset of prolonged psychosis in vulnerable individuals making it critically important to investigate the mental history of family members before taking any psychedelic. 

Another important consideration, is the integration of the experience into your daily life.  While taking psilocybin mushrooms, or other psychedelics, unconscious material may be brought to the surface during the session and if it is not worked through or integrated properly, may lead to negative emotions or experiences after the session has ended (27).

Reports of complications are extremely rare, especially in supervised and controlled circumstances.

Moderate doses of psilocybin appear to be well-tolerated. With that being said, certain people should avoid using psilocybin.

Do NOT Take Psilocybin If… 

• You don’t understand what psilocybin is and its potential effect
• You’re feeling pressured to take psilocybin because of others
• You’re taking antidepressants such as SSRIs or antipsychotic medication
• You’re pregnant or there’s a chance you are
• You do not trust the person who is giving you psilocybin
• You have a family history of mental health conditions such as schizophrenia, bipolar disorder or borderline personality disorder
• You have severe clinical depression
• You have or have had suicidal thoughts, attempts or instances of self-harm
• You have a panic attack disorder

Pharmacological Contraindications 

Psilocybin interacts with the serotonergic system in the brain. Most typical antidepressants/mood regulators also interact with the serotonergic system (and others) in one way or another. The combination of psilocybin and antidepressants can result in ‘serotonin syndrome’ which can be fatal. To be safe, it is highly recommended to avoid taking psilocybin with the following medications:

• Selective Serotonin Reuptake Inhibitors (SSRIs).
• Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs).
• Monoamine Oxidase Inhibitors (MAOIs).
• Tricyclic Antidepressants (TCAs).
• Tetracyclic Antidepressants (TeCAs).
• Norepinephrine Reuptake Inhibitors (NRIs).
• Norepinephrine-Dopamine Reuptake Inhibitors (NDRIs)
• Serotonin Modulators and Stimulators (SMRIs).
• Serotonin Antagonists and Reuptake Inhibitors (SARIs).
• Lithium – there have been reports of death, heart failure, seizures.

Some users have reported that combining their medications with psilocybin produces a diminished effect or no effect at all. Others have become extremely ill and deaths have been reported in rare instances. The safest approach is to NOT MIX any classic psychedelic with your medications. For a more comprehensive list of drug interactions please visit: http://wiki.tripsit.me/wiki/Drug_combinations

You can read more about potential adverse drug interactions with psilocybin here.

Addiction Potential

Like any substance, psilocybin mushrooms can be abused, used in ways that compromise the safety of the individual and others.  However, there is no evidence that they create dependence or withdrawal symptoms (28).On the contrary, psilocybin research since the 1950s coupled with recent clinical trials has made the case for psilocybin being an effective treatment for addiction (29).  When used in the correct manner, psilocybin is one of the safest ‘drugs’ to consume therapeutically or recreationally (30,31).   

Despite the low addictive potential and toxicity of psilocybin, abuse is still possible. Consistent high doses of psilocybin may cause difficulty in adjusting back to reality, especially if psilocybin is being used as an escape from reality, rather than a tool to help improve wellbeing.

Long-Term Effects

In a 2011 review, of 110 healthy patients (32), researchers evaluated the short and long-term safety of psilocybin and no indication of drug abuse, nor persisting perceptual disorders (aka flashbacks,) or prolonged psychosis occurred.  However  in a small number of  cases, with the highest doses of psilocybin, short term anxiety/panic did occur.  These adverse reactions were managed with interpersonal support without pharmaceutical intervention.  Long-term negative side effects were not present.

A study reports that one strong dose of hallucinogenic mushrooms can alter a person’s personality for at least 14 months and perhaps permanently. These long term personality changes are thought to result from having a mystical experience, profound feelings of transcendence that are often triggered by psilocybin mushrooms (33). 

Harm Reduction Measures

• Know why you are taking psilocybin mushrooms
• If it’s your first time, start slow. You can always take more, but you can never take less. Keeping this philosophy in mind, with any substance you consume, will minimize unnecessary harm. 
• Use psilocybin mushrooms in a safe and comfortable environment
•  An additional, though rare risk, is the cross-mutation of psilocybin mushrooms with  toxic mushroom species.  
• If you experience symptoms of mushroom poisoning such as muscle spasms, delirium, and confusion, visit an emergency room immediately. To ensure you decrease the risk of accidental poisoning, purchase psilocybin mushrooms from a regulated source rather than picking them yourself.

For more information on psilocybin mushrooms, visit ICEERS.

Psilocybin mushroom safety considerations

Information about integration