Two-thirds of people who underwent psilocybin-assisted therapy remained free from depression five years later, according to recent research that offers the first long-term glimpse into the lasting power of psychedelic treatment.
Author
- Petri Kajonius
Associate Professor, Personality Psychology, Lund University
The findings , published by researchers at Ohio State University and Johns Hopkins University, followed up participants from a study published in 2021 to track whether the dramatic improvements in depression symptoms would endure. The results suggest they do - and, remarkably, without serious side-effects.
The original study involved 24 people aged 21 to 75 who were randomly assigned to receive psilocybin treatment in 2019 and 2020 either immediately or after an eight-week delay. Each participant received two doses of the psychoactive compound found in magic mushrooms, spaced two weeks apart, alongside 13 hours of psychotherapy support.
When researchers checked in five years later, the improvements in depression seen after one year were still holding strong, suggesting psilocybin therapy may last longer than traditional treatments, such as antidepressants or psychotherapy.
But the researchers are cautious about overselling their findings. The follow-up study lacked a comparison group, making it impossible to know whether people who recovered from depression through other means might experience similar long-term success. Eleven of the 18 participants who remained in the trial also reported using antidepressants during the study period, muddying the waters about what exactly drove their continued recovery.
The study design presents other puzzles as well. Was it the psilocybin itself that proved beneficial, or the extensive psychotherapy, or some combination of both? The original research didn't include a placebo group - everyone knew they were taking psilocybin - raising questions about whether expectations alone might have influenced the outcomes.
Despite these limitations, other studies are painting a similar picture of psilocybin's enduring effects on depression. While psychedelic research is still in its infancy and grapples with design challenges, the results consistently show significant reductions in depression symptoms following psychedelic-assisted therapy.
What makes these findings particularly intriguing is the suggestion that just one or two treatment sessions might deliver lasting benefits. This is in stark contrast to traditional antidepressants, which typically require daily use and often come with a catalogue of side-effects .
The researchers propose that psilocybin therapy may trigger "positive behavioural feedback loops", helping people gain fresh perspectives and emotional insights that continue benefiting their lives long after the treatment ends. This could enable the development of healthier habits and relationships that serve as natural buffers against depression's return.
One participant captured this transformation vividly: "I'm doing more of activities that I enjoy. My life these days is a lot more social with family. Helping out my family. Helping out friends. Connecting with old friends."
Psychology matters
At Lund University in Sweden, my colleagues and I are exploring similar territory, including an upcoming study on psilocybin and anorexia . And our early results , published in Scientific Reports, suggest that individual psychology plays a crucial role in both how people experience psychedelic sessions and the benefits they derive from them.
The picture becomes even more complex when considering that many people report personality changes after psychedelic experiences, particularly becoming more open to new experiences . This psychological shift adds another layer to understanding how and why psychedelics might produce lasting change.
Psychedelic research still faces significant hurdles, from creating convincing placebo groups to accounting for the self-selecting nature of many participants. These methodological challenges make it difficult to draw sweeping conclusions about psychedelics' therapeutic potential.
Yet perhaps the most compelling evidence lies not in clinical scores but in participants' own words about their transformed lives. As one person put it: "I think I'm more open to gratitude and more open to delight." Such testimonies remind researchers why they're exploring what some describe as potentially "one of the most meaningful experiences in life" - and why this emerging field of medicine deserves serious scientific attention.
Petri Kajonius does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
