A growing number of scientists are studying whether psychedelic substances could help treat mental health disorders.
One of the most researched substances is psilocybin, a natural psychedelic compound found in certain mushrooms often called “magic mushrooms.”
Now, a new study from Sweden suggests that a single dose of psilocybin may rapidly reduce symptoms of depression.
Researchers at Karolinska Institutet found that people with moderate to severe depression experienced major improvements within days after treatment. Some benefits lasted for more than three months.
The findings were published in the medical journal JAMA Network Open.
Depression is a major global health problem that affects mood, energy, thinking, sleep, and daily functioning. Many patients struggle for years with repeated episodes of sadness and emotional distress.
Traditional antidepressant medications, especially SSRIs, are widely used to treat depression. However, these medicines do not help everyone, and they often take weeks before patients notice improvements.
Some patients also stop treatment because of unpleasant side effects.
Because of this, researchers have become increasingly interested in whether psychedelic-assisted therapy could provide faster symptom relief.
The Swedish study included 35 adults aged 20 to 65 who had recurrent depression ranging from moderate to severe.
Participants were randomly assigned to receive either a single 25-milligram dose of psilocybin or a placebo treatment.
The placebo consisted of niacin, a vitamin that can create mild physical effects such as skin warmth or flushing. Researchers used this “active placebo” to make it harder for participants to know which treatment they had received.
The study was designed as randomized and double-blind, meaning neither the participants nor the doctors assessing results officially knew which treatment each person received during the trial.
In addition to the medication, all participants received psychological support before, during, and after treatment sessions.
During dosing, participants rested quietly while wearing eye masks and listening to music through headphones.
Researchers evaluated changes in depression symptoms using the MADRS scale, a standard clinical rating system for depression.
The main results were measured eight days after treatment.
Participants who received psilocybin showed much greater improvement compared to those receiving placebo.
On average, depression scores dropped by 9.7 points in the psilocybin group compared to only 2.4 points in the placebo group.
Researchers considered this difference clinically meaningful.
Self-reported assessments also suggested improvements appeared very quickly, sometimes within only two days after treatment.
The antidepressant effects remained noticeable after 15 days and 42 days.
Six weeks after treatment, more than half of participants in the psilocybin group were considered to be in remission from depression. Only a small number of placebo participants reached remission during that period.
Researchers say the speed of improvement is especially important because rapid symptom relief is difficult to achieve with many standard antidepressants.
However, scientists caution that the study was relatively small and involved only one treatment session.
They also stress that psychedelic therapy is not completely risk-free.
Most side effects in the study were mild and temporary, but two participants experienced severe anxiety lasting long enough to require medical attention.
Researchers therefore emphasize that psilocybin treatment should only occur under professional supervision in carefully controlled medical environments.
The study also highlights one of the biggest challenges in psychedelic research.
Because psilocybin produces powerful psychological effects, many participants correctly guessed which treatment they had received.
This creates a possible “expectation effect,” where people may feel better partly because they believe they received the active treatment.
The researchers say future studies will need to better separate the biological effects of psilocybin from the influence of expectations and psychotherapy support.
Scientists are also trying to understand how psilocybin affects the brain itself.
Some evidence suggests depression may involve weakened communication between brain regions and reduced flexibility in neural networks.
Animal studies have shown that psychedelics may increase synaptic growth, meaning they may help brain cells form new connections.
The research team plans to analyze brain imaging scans along with blood and spinal fluid samples collected before and after treatment.
These studies may help reveal whether psilocybin physically changes brain activity or connectivity in ways linked to mood improvement.
Experts say the findings are promising but still preliminary.
Larger studies involving more participants and repeated treatments will be needed before psilocybin could become a standard medical therapy.
Researchers also want to determine how long the benefits last and whether repeated sessions might help prevent relapse.
Even so, the study adds to growing international interest in psychedelic medicine as a possible new approach for treating depression and other mental health conditions.
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The study was published in JAMA Network Open.
Source: Karolinska Institutet.
