A preliminary study published this month in JAMA Psychiatry presents evidence that psilocybin, the psychedelic ingredient in Psilocybe cubensis, or so-called magic mushrooms, may be a useful treatment for depression when paired with psychotherapy.
In the study, researchers assessed the effects of psilocybin on 24 people with depression, who were separated into two groups. The first group of 13 people received psilocybin at the beginning of the study, while another 11 people began the psilocybin treatment eight weeks later. The delay allowed them to serve as a comparison group, Jon Hamilton reports for NPR. The researchers found an almost immediate improvement in the first group of people after they completed their psilocybin treatment.
The study was small, lacked diversity in its participants and may have been affected by the volunteers’ expectations of taking the psychedelic drug. However, the results do suggest that this may be a fruitful path forward in the search for new antidepressants.
“The current results are clear,” says Harvard University psychologist Jay Olson, who wasn’t involved in the study, to Science News’ Laura Sanders. “At least for some people, psilocybin can reduce depression better than several common treatment options.”
To assess the participants' depression symptoms throughout the experiment, the JAMA Psychiatry study researchers referenced a 17-part scale commonly used in clinical trials in which patients rate their symptoms. Any total below 7 indicates no depression, scores between 8 to 16 suggest mild depression, 17 to 23 is moderate depression and scores over 24 indicate severe depression.
The new study used the same scale to measure how effectively psilocybin alleviates depression symptoms over time. The first group began the study with an average score of 22.9 points, and four weeks after completing the course of treatment, the same group had an average score of 8.5 points.
A previous study had shown that psilocybin helped patients with life-threatening cancer cope with the depression and anxiety that accompanied their diagnosis. That study "led us to consider whether or not this treatment might be effective for people in the general depression community," says Alan Davis, author of the new study and a psychiatrist at Johns Hopkins University and Ohio State University, to NPR.
Davis and his colleagues recruited over 800 initial volunteers and then pared down the study group, excluding people who were currently using antidepressants, were unable to take an MRI, had another mental health diagnosis that could interfere with the study, among other things. The group ended up with 27 eligible volunteers, and three dropped out during the course of the study.
The 24 study participants received 11 hours of psychotherapy as well as two doses of supervised psilocybin treatment, given on different days. Davis tells NPR that the participants received the psilocybin in a homey setting meant to help them relax.
"They have a blindfold on, they have headphones on, listening to music," Davis tells NPR. "And we really encourage them to go inward and to kind of experience whatever is going to come up with the psilocybin."
The improvement in the participants’ depression was faster than traditional antidepressants, which don’t work for about 30 to 50 percent of people who try them, reports Science News.
The authors concede that the positive effect of the psilocybin might have been increased by the participants’ anticipation of taking the drug. The study also lacked long-term follow-up with the participants, so it does not show whether the psilocybin’s effect is long-lasting, University of Oxford psychiatrist Guy Goodwin tells Katie Hunt at CNN. The study setting may have also improved participants’ mood, Goodwin says.
"You get an effect irrespective of whether the treatment works because everyone is caring for you and looking out for you and measuring things. People like that and feel better for that. In a real comparison you'd do everything the same but the actual drugs," says Goodwin to CNN, adding that larger studies are underway.
Of the JAMA Psychiatry study, Goodwin says it “is a nice, small preliminary study with a lot of weaknesses but equally the positive results promise better things."
University of Pittsburgh psychiatrist Charles F. Reynolds III describes the new study as scientifically rigorous. "It offers, I think, a good deal of promise as a feasible approach to treating particularly chronic forms of depression," Reynolds tells NPR.
Further research will be needed to help scientists understand who might benefit from psilocybin over other antidepressants. Of the 24 participants in the JAMA Psychiatry study, there was only one Asian person and one African American person, reports Science News.
“We really need to think more about who we are including in these studies,” says University of Ottawa psychologist Monnica Williams, who wasn’t involved in the study, to Science News. Past, negative experiences in healthcare settings might shape a person’s response to a psychedelic treatment. “A person of color might have a lot of reasons to feel very guarded and anxious in that situation, which is going to make it harder for that approach to be effective.”