A Single Dose Of Psilocybin Can Lead To ‘Rapid’ And ‘Long-Lasting’ Improvements In Depression, Study Indicates

A single dose of psilocybin, coupled with therapy sessions, significantly improved symptoms of depression within days and lasting for a period of months, according to a first-of-its-kind study out of Sweden that was published by the American Medical Association.

Researchers at Karolinska Institutet and the Brain Stimulation Clinic in Stockholm conducted the phase 2 randomized clinical trial, which involved 35 participants with moderate-t0-severe depression who received either a 25 milligram dose of psilocybin or a placebo of niacin.

For the study, published in JAMA Psychiatry last week, patients also underwent five psychotherapy sessions to supplement the psychedelic or placebo experience.

The psilocybin cohort, on average, showed clinically observable improvement in their symptoms compared to the placebo group at day 8.

“This finding implies that psilocybin can be an option to standard treatments when rapid symptom relief is important,” the paper says.

“A single dose of psilocybin was associated with rapid antidepressant effects.”

By the sixth week of the trial, 53 percent of the psilocybin cohort were considered to be in remission for depression, while just 6 percent of the placebo group said the same by that point.

However, researchers found that the overall effect seemed to subside after a year.

”Our results suggest that psilocybin can provide rapid, clinically meaningful improvement in depression and may serve as an alternative to standard treatment when fast symptom reduction is important,” lead study author Hampus Yngwe said in a press release.

”However, the long-term effects are uncertain. Repeated treatments may be needed to prevent relapse,” he said. “This needs to be investigated in larger studies.”

“Our findings indicate that psilocybin might be a valuable addition to current treatments because of its rapid onset and relatively long-lasting effects, although the duration may not be as long as suggested by previous uncontrolled studies. Repeated dosing or maintenance therapy might therefore be needed to prevent relapse.”

Johan Lundberg, a neuroscience professor at Karolinska Institutet, added that “it is important to emphasize that the treatment is not risk-free and that some patients may need extra support.”

This marks the first randomized, double-blind study in Sweden investigating psilocybin for depression. Researchers received funding from the Swedish Research Council and Norrsken Mind.

However, it’s hardly the only study suggesting that single-dose psychedelic therapy may have lasting impacts in the treatment of various mental health conditions.

For example, another recent study published by the American Medical Association (AMA) found that one dose of psilocybin, with integrated psychotherapy, appears to be a “safe and efficacious” treatment option for people with cocaine use disorders (CUD).

That research was being published about two months after AMA released a separate study finding that a single dose of psilocybin combined with therapy is associated with “significantly increased long-term abstinence” from cigarettes compared to nicotine patches. That indicates the psychedelic “holds potential in the treatment of tobacco use disorder,” the researchers said.

As psychedelics policy reform advances in state legislatures across the U.S. and in Congress, Americans have shown growing interest in exploring the therapeutic potential of substances like psilocybin. To that point, a RAND Corporation analysis recently found that nearly 10 million American adults microdosed psychedelic drugs such as psilocybin, LSD or MDMA in 2025.

A scientific review published by AMA last year that use of psilocybin has “surged” in the U.S. in recent years amid the decriminalization movement and in light of “promising clinical trial results” on its therapeutic potential. But the paper also pointed out that current federal laws present “a major barrier” to researchers gaining a better understanding of the psychedelic substance’s true impacts.

Meanwhile, another study from last year found that psilocybin-assisted psychotherapy “showed significant reductions in alcohol consumption and high smoking cessation rates” and has potential to lessen opioid dependence.

In 2024, meanwhile, two other studies—including one with contributions from a top federal drug official—examined psychedelics and alcohol use disorder (AUD).

One found that a single dose of psilocybin “was safe and effective in reducing alcohol consumption in AUD patients,” while the other concludes that classic psychedelics like psilocybin and LSD “have demonstrated potential for treating drug addiction, especially AUD.”

The National Institutes of Health that year also announced that it would put $2.4 million toward funding studies on the use of psychedelics to treat methamphetamine use disorders—funding that came as federal health officials noted sharp increases in deaths from methamphetamine and other psychostimulants in recent years, with fatal overdoses involving the substances rising nearly fivefold between 2015 and 2022.

In 2023, the National Institute on Drug Abuse (NIDA) announced a $1.5 million funding round to further study psychedelics and addiction.

Meanwhile, the Trump administration has recently taken steps to explore the therapeutic potential of psychedelics such as ibogaine, which has been touted as a potentially life-saving treatment option for people suffering from serious mental health conditions such as post-traumatic stress disorder (PTSD) and substance use disorder.

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Other research has also suggested that psychedelics could unlock promising new pathways to treat addiction. A first-of-its-kind analysis in 2023 offered novel insights into exactly how psychedelic-assisted therapy works for people with alcohol use disorder.

In 2024, the National Center for Complementary and Integrative Health (NCCIH), which is part of the National Institutes of Health (NIH), identified the treatment of alcohol use disorder as one of a number of possible benefits of psilocybin, despite the substance remaining a Schedule I controlled substance under U.S. law.

The agency highlighted a 2022 study that “suggested that psilocybin may be helpful for alcohol use disorder.” The research found people who were in psilocybin-assisted therapy had fewer heavy-drinking days over 32 weeks than the control group, which NCCIH said “suggests that psilocybin may be helpful for alcohol use disorder.”

Photo courtesy of Dick Culbert.

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