Psilocybin, the psychedelic compound in ‘magic’ mushrooms, may be an effective way to treat depression in patients who have not benefited from other standard treatments, initial results show.
In a pilot study involving just 12 people with treatment-resistant depression, two doses of the mushroom compound cleared symptoms in eight participants — 67 percent — after one week. After three months and no other doses, seven participants still reported reduced depressive symptoms, including five — 42 percent — who reported complete remission of their depression.
But the finding, published Tuesday in the Lancet Psychiatry, is only a first step to assess the safety of using the hallucinogenic drug. With such a small study, no controls and non-randomized participants, it is not possible to determine whether the promising efficacy results will hold.
“We’re just saying this is doable,” Robin Carhart-Harris, a neuropsychopharmacologist at Imperial College London and first author of the study, told me. Nature. “We can give psilocybin to depressed patients, they can tolerate it and it’s safe.”
Carhart-Harris and colleagues came up with the idea to try psilocybin after previous brain imaging studies showed that the compound activated brain regions associated with antidepressant effects. In addition, large population studies have shown that people who have used psychedelics during their lifetime experience fewer mental health problems and suicidal episodes than those who did not.
In addition, psilocybin is easily converted into psilocin in the body, which can activate serotonin receptors. These receptors, which affect a wide variety of biological processes such as learning, memory and mood, are also targets of more standard treatments for depression, namely selective serotonin reuptake inhibitors (SSRIs) such as Celexa and Prozac.
After a tedious approval process for the first trial, the research team enrolled the 12 participants, who had moderate to severe depression and had not seen benefits from at least two other treatments. While psychiatrists stood by, the researchers started the participants with just a small dose of 10 milligrams of psilocybin to test their tolerance. A week later, they gave the participants a dose of 25 mg, which was considered the test amount.
Psilocybin has very low toxicity and low risk of addiction. During the study, the authors reported no adverse effects during the trial, aside from mild, transient anxiety, nausea, and headache.
While the efficacy, according to Carhart-Harris, was “quite remarkable,” much more work will need to be done to prove that psilocybin can reliably treat depression. For starters, five of the 12 participants had previously been exposed to the drug and may be more tolerant of the drug and more positive about the experience they gained from the study.
Overall, the study’s finding “motivates further studies, with more rigorous designs, to better explore the therapeutic potential of this approach,” the authors conclude.
Lancet Psychiatry2016. DOI: 10.1016/S2215-0366(16)30065-7 (About DOIs).