Introduction

Cancer can affect anyone, whether it’s directly or indirectly. The American Cancer Society estimates that in the United States, 40% of men and 39% of women will be diagnosed with cancer during their lifetime. Even for people with no history of mental health issues, the diagnosis can bring on anxiety and depression — and the symptoms can be severe. Unfortunately, although mental health practitioners may treat these conditions with antidepressants, anti-anxiety drugs, and psychotherapy (aka talk therapy), these traditional remedies aren’t always effective.^(1, 2)

However, mental health professionals may soon have a new tool to treat depression and anxiety: psilocybin. Commonly known as magic mushrooms, this psychedelic drug shows promise for easing the psychological distress associated with cancer. Several prominent studies and clinical trials are pushing the research forward and offering new insights into the potential mental health benefits.

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Understanding the Link Between Cancer and Mental Health

Cancer doesn’t only impact the body. Waiting for test results, undergoing treatments, and worrying about recurrence can impact an individual’s mental health, causing them to feel depressed or anxious. Regardless of where they are in their journey through diagnosis and treatment, the emotional distress that comes with cancer may:

Severe depression may even negatively impact a patient’s prognosis.⁽³⁾

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A Brief History of Psilocybin (“Magic Mushrooms”)

Psilocybin mushrooms (aka magic mushrooms) grow naturally in the U.S., Canada, South America, Europe, parts of Africa, Central America, and Mexico. Psilocybin is considered a hallucinogen and has been known to bring on significant spiritual and mystical states of consciousness in those who take it. For some users, this can positively impact how they think, emote, and behave.⁽⁴⁾

Because of its effects, psilocybin has been used in religious, spiritual, and healing ceremonies. The substance is taken orally and is often brewed in tea to mask its bitter taste. However, as a prohibited Schedule I substance under the Controlled Substances Act, psilocybin is currently illegal in most of U.S. states.

Today, however, amid campaigns to decriminalize magic mushrooms on local levels, researchers are showing interest in psilocybin for another reason — it’s potential to aid in the treatment of cancer-related depression and anxiety.

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Can Psilocybin Treat Cancer-Related Depression and Anxiety?

From its introduction to Western culture in the 1950s — and for years afterwards — researchers studied psilocybin’s effect on the symptoms of depression, addiction, and anxiety. Unfortunately, once people began associating magic mushrooms and other psychedelics with the counterculture movement, these substances were stigmatized and later prohibited altogether. As a result, research into possible uses of the compound essentially stopped.

However, research has begun again in recent years, and some studies suggest that psilocybin may reduce depression and anxiety in individuals with cancer and other life-threatening illnesses. Moreover, psilocybin has been awarded the Breakthrough Therapy designation by the FDA to treat major depressive disorder (MDD), which expedites the development of new drugs. As researchers continue to add to the evidence indicating psilocybin is generally safe and has potentially life-changing medical applications, legislators and the public are becoming more open to its potential benefits. States like Oregon and Colorado have legalized psilocybin for therapeutic use, and municipalities across the nation are beginning to decriminalize magic mushrooms.⁽⁵⁾

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What Current Research Says About the Role of Magic Mushrooms in Mental Health Treatment

The Heffter Research Institute stands at the forefront of current research into the potential benefits of psilocybin. Founded in 1993 in New Mexico as a nonprofit scientific organization, the institute aims to advance high-quality studies of classic hallucinogens and related substances — looking at their potential to treat substance use disorders and other mental health conditions. Since its founding, it has designed, reviewed, and funded leading research studies on psilocybin throughout the U.S. and Europe. Heffter-affiliated scientists account for more than 60% of top-cited research papers on classic psychedelics.⁽⁶⁾

To further examine psilocybin’s potential to manage cancer-related symptoms of anxiety and depression, the institute partnered with the leading research powerhouse: Johns Hopkins Center for Psychedelic and Consciousness Research.

Here we cover two of the most impactful studies that examined psilocybin’s efficacy and long-term benefits.

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Study 1: Does the Dose of Psilocybin Matter?

The first study, which was featured in the Journal of Psychopharmacology in 2016, evaluated how individuals responded to low and high doses of psilocybin. The participants were comprised of 51 individuals diagnosed with cancer and cancer-related depression, anxiety, or both, as defined in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV).⁽²⁾

Researchers randomly divided participants into two groups. The first group received a low dose of psilocybin (1 or 3 milligrams) during the first session and a high dose (22 or 30 milligrams) during the second session, with five weeks in between doses. In the second group, the doses were reversed, with participants receiving the high dose first, followed by the low dose, which was similar to a placebo. In other words, the low dose was intended to be a control. The research team didn’t intend for that dose to have a physiological effect on those who took it.

During the study, researchers asked the participants, staff, and community observers to rate the participants’ moods, attitudes, and behaviors. They then evaluated data taken at various points in the study, including information received immediately after enrollment. They also looked at ratings taken on days when the participants received psilocybin, about five weeks after each session, and six months after participants received the last dose. This was a double-blind study, meaning neither the participants nor the researchers knew which treatment each individual received until the study was completed.

The results showed promise. When participants took higher doses of psilocybin, they experienced more improvement in their depressed mood and anxiety (as reported by themselves and study researchers) than those who took lower doses. In general, the high-dose recipients experienced a better quality of life, more life meaning, more optimism, and a decreased fear of death. Notably, they believed these improvements were due to psilocybin use. At the 6-month follow-up, about 80% of the participants still benefited from decreased symptoms of depression and anxiety.⁽²⁾

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Study 2: Is It the Placebo Effect?

In the institute’s second study, which was also featured in the Journal of Psychopharmacology in 2016, a different group of researchers aimed to assess the effectiveness of a single dose of psilocybin compared to a placebo pill that contained only niacin, a B3 vitamin. The 29 patients in this study were all experiencing anxiety and/or depression related to advanced cancer. In addition to taking psilocybin or niacin (they wouldn’t know which), they engaged in traditional psychotherapy.

As they did in the first study, researchers randomly divided participants into two groups. The first group received psilocybin first, followed by niacin. The second group received niacin first, then psilocybin, in the same doses. Both groups got their first dose two to four weeks after their initial assessment. The second dose was administered seven weeks later.

Throughout the study, researchers evaluated the data, which included symptoms recorded at several different times: when participants entered the study, a day before they got the dose, the day they received a dose, a day after a dose, and six weeks after each dose. Participants were assessed as late as 26 weeks after the second dose.

Mainly, the researchers looked at each individual’s levels of anxiety and depression before the treatment changed, either from psilocybin to niacin or vice versa. However, they also considered the participants’ quality of life, their level of distress, changes to their spirituality, and the effects of the compound on cognition and behavior.

Eventually, the researchers concluded that when combined with psychotherapy, a single moderate dose of psilocybin quickly and effectively eased symptoms of anxiety and depression in patients with cancer-related psychological distress. Consequently, participants had fewer feelings of demoralization and hopelessness and increased feelings of spiritual well-being.

Moreover, at the six-month follow-up, about 60–80% of participants continued to show improvement in their depression and anxiety symptoms. In addition to having an improved quality of life, they had less anxiety about death. The study also found that psilocybin treatment offers a rapid, sustained reduction in symptoms of depression and anxiety in individuals with terminal cancer.⁽⁴⁾

It’s also worth noting that the second group, which received niacin first, didn’t experience any significant improvements until they received psilocybin. Then, they experienced immediate and lasting improvements in their symptoms. 

Importantly, the researchers didn’t record any serious adverse events involving either psilocybin or niacin. Some side effects were noted, but they passed quickly and were easily tolerated. These side effects were similar to those experienced during other studies of magic mushrooms.

A systematic review of multiple psilocybin trials found that common side effects include:⁽⁷⁾

These results were published in the Icelandic Medical Journal in 2022.

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What These Psilocybin Studies Could Mean for Cancer Patients

Although antidepressants, anti-anxiety drugs, and psychotherapy may alleviate symptoms of cancer-related depression and anxiety, they aren’t 100% effective. This is one reason researchers have a renewed interest in psilocybin’s potential for treating anxiety and depression, in general, and mental health conditions associated with terminal cancer, in particular. To date, it’s shown it can be used safely in controlled doses, in medical settings, and under medical supervision.⁽²⁾

The studies described above offer hope that anxiety and depression associated with life-threatening cancer may be managed with psilocybin. However, larger, well-designed studies are needed to confirm these findings. Psilocybin is considered an experimental drug and is still classified as a Schedule I controlled substance, and using magic mushrooms in uncontrolled settings is still illegal in most states.

By demonstrating psilocybin’s safety and efficacy, researchers can begin to shift public opinion. This, in turn, has the potential to change hard-line stances held by legislators, possibly opening the door to further reforms to how psilocybin and psychedelics as a whole are handled. Potentially, opening the doors to expanded research to find treatments for other conditions.