Users of magic mushrooms — a term that describes varieties of mushrooms that contain the psychoactive substance psilocybin — often experience intense elation, an altered perception of reality, and hallucinations (also known as “tripping”).
Psychedelic mushrooms may point to new ways to treat depression, suggest two small brain imaging studies that seem to show how psilocybin — the active ingredient in such mushrooms — affects the brain.
One study included 30 healthy people who had psilocybin inserted into their blood while magnetic resonance imaging (MRI) scanners measured changes in their brain activity. The scans revealed that psilocybin caused decreased activity in what the researchers described as the brain's "hub" regions — areas especially well-connected with other areas.
The second study included 10 healthy volunteers and found that psilocybin boosted their recall of personal memories and their emotional well-being for up to two weeks. The researchers said this suggests that psilocybin might prove useful as an adjunct to psychotherapy.
A study published in 2014 found that people with anxiety who received a single psilocybin treatment had lower depression scores six months later. David Nutt, who is with the Department of Medicine at Imperial College London, was the senior author of both of the new studies.
"Psychedelics are thought of as 'mind-expanding' drugs, so it has commonly been assumed that they work by increasing brain activity, but surprisingly, we found that psilocybin actually caused activity to decrease in areas that have the densest connections with other areas," Nutt said in a college news release. "These hubs constrain our experience of the world and keep it orderly. We now know that deactivating these regions leads to a state in which the world is experienced as strange."
The impact of psilocybin reported by the study participants — such as seeing "geometric" patterns, experiencing an altered sense of time and space, and unusual physical sensations — correlated with a decreased flow of oxygen and blood to parts in the brain's posterior cingulate cortex and medial prefrontal cortex (mPFC), the study authors said.
It has thought that the posterior cingulate cortex plays a role in consciousness and self-identity. Research has shown the medial prefrontal cortex to be especially active in people struggling with depression, so psilocybin's effect on this area of the brain could be responsible for some of the antidepressant effects reported in previous research, the study authors said.
Nutt and his colleagues also found that psilocybin reduced blood flow in the hypothalamus, where blood flow increases in people with cluster headaches. Some headache sufferers have reported that psilocybin improved their symptoms.
"Psilocybin was used extensively in psychotherapy in the 1950s, but the biological rationale for its use has not been properly investigated until now. Our findings support the idea that psilocybin facilitates access to personal memories and emotions," Dr. Robin Carhart-Harris, from the Department of Medicine at Imperial College London, and first author of both studies, said in the news release.
"Previous studies have suggested that psilocybin can improve people's sense of emotional well-being and even reduce depression in people with anxiety. This is consistent with our finding that psilocybin decreases mPFC activity, as many effective depression treatments do. The effects need to be investigated further and ours was only a small study, but we are interested in exploring psilocybin's potential as a therapeutic tool," Carhart-Harris added.
The study authors reiterated that both trials contained small numbers of participants, and further research into psilocybin's effects on the brain is needed.
The main focus of one of the older studies was related to the exploration of the similarities between hallucinogenic experiences and the life-changing revelations, reported throughout history by religious mystics and those who meditate. These similarities have been identified in neural imaging studies conducted by Swiss researchers and in experiments led by Roland Griffiths, a professor of behavioral biology at Johns Hopkins.
In one of Dr. Griffiths’s first studies, involving 36 people with no serious physical or emotional problems, he and colleagues found that psilocybin could induce what the experimental subjects described as a profound spiritual experience with lasting positive effects for most of them. None had had any previous experience with hallucinogens, and none were even sure what drug was being administered.
To make the experiment double blind, neither the subjects nor the two experts monitoring them knew whether the subjects were receiving a placebo, psilocybin or another drug like Ritalin, nicotine, caffeine or an amphetamine. Although veterans of the ’60s psychedelic culture may have a hard time believing it, Dr. Griffiths said, that even the monitors sometimes could not tell from the reactions whether the person had taken psilocybin or Ritalin.
The monitors sometimes had to console people through periods of anxiety, Dr. Griffiths said, but these were generally short-lived, and none of the people reported any serious negative effects. In a survey conducted two months later, the people who received psilocybin reported significantly more improvements in their general feelings and behavior than did the members of the control group.
The findings were repeated in another follow-up survey, taken 14 months after the experiment. At that point, most of the psilocybin subjects once again expressed more satisfaction with their lives and rated the experience as one of the five most meaningful events of their lives.
Since that study, which was published in 2008, Dr. Griffiths and his colleagues have gone on to give psilocybin to people dealing with cancer and depression, like Dr. Martin, the retired psychologist from Vancouver. Dr. Martin’s experience is fairly typical, Dr. Griffiths said: an improved outlook on life after an experience in which the boundaries between the self and others disappear.
Magic Mushrooms to become Mainstream Antidepressant?
Depression is estimated to affect more than 350 million people around the world, according to the World Health Organization. The current pharmaceutical approach to treatment is with selective serotonin re-uptake inhibitors (SSRIs), such as Prozac, which increase levels of serotonin in the brain to improve moods. But SSRIs are not effective in everyone, take time to show an effect and are generally prescribed for long periods of time to maintain their effect.
David Nutt thinks psilocybin could be a game-changer, used as part of a therapeutic package where the mind-altering and confronting nature of psychedelics are combined with therapy to treat people within just one or two doses of treatment. "We've never had drugs before with an instant effect. This could create a paradigm shift to help people into a different state of thinking that they can then stay in," he says.
But he stresses that psilocybin should be administered with professional support as part of medical therapy.
Psilocybin is illegal in many countries and in the United States, it is considered a Schedule 1 drug. Schedule 1 drugs "have a high potential for abuse and serve no legitimate medical purpose in the United States," according to the Department of Justice.
The U.S. National Institute of Drug Abuse says that long-term negative effects such as flashbacks, a risk of psychiatric illness and impaired memory have been described in case reports. Some people have frightening experiences while on psilocybin and can experience panic reactions, which may cause them harm to themselves or others.
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