Does Psilocybin Cure Depression Long-Term? What 5-Year Data Shows

Introduction

Psilocybin depression long-term results have been the most urgent unanswered question in psychedelic medicine — and in September 2025, researchers at Ohio State University and Johns Hopkins University published the first answer. The landmark five-year follow-up study tracked participants from a 2021 clinical trial of psilocybin-assisted therapy for major depressive disorder. What they found challenges nearly everything we assume about how antidepressant treatment works.

Two-thirds of patients who underwent psilocybin-assisted therapy remained free from depression five years later. Not months. Years. After just two doses of psilocybin, combined with approximately 13 hours of psychotherapy support, the majority of participants were not only still in remission — they were showing improvements in anxiety, functioning, empathy, and quality of life that had continued to grow over the five-year period.

This guide breaks down exactly what the study found, what it means, what its limitations are, and why these psilocybin depression long-term results represent such a significant moment in the history of psychiatric medicine. For a full understanding of the neurological mechanisms behind these outcomes — including the default mode network disruption and neuroplasticity that drive them — see our deep dive: The Science Behind Psilocybin & the Brain: What 2026 Research Actually Says.

The Study: What Happened

The five-year follow-up was led by Dr. Alan Davis, associate professor and director of the Center for Psychedelic Drug Research and Education at Ohio State University — who co-led the original 2021 trial at Johns Hopkins University. The findings were published in the Journal of Psychedelic Studies in September 2025.

The original 2021 trial:

• 24 adults aged 21–75 with a diagnosis of major depressive disorder
• Not currently using antidepressant medications
• Randomly assigned to receive treatment immediately or after an 8-week delay
• Each received two doses of psilocybin, approximately two weeks apart
• Supported by approximately 13 hours of psychotherapy across preparatory, dosing, and integration sessions

The original results were striking — large reductions in depression scores within one week, with 75% response and 58% remission at 12 months. But what happened next was the crucial question: do psilocybin depression long-term results hold, or does the effect fade?

The five-year follow-up:

• Of the original 24 participants, 21 enrolled in the long-term follow-up
• 18 (75%) completed the full follow-up assessment
• Average follow-up period: 5.37 years
• Primary measure: clinician-rated depression severity (GRID-Hamilton Depression Rating Scale)

The Results: What the 5-Year Data Actually Shows

The psilocybin depression long-term results were, by any standard in psychiatric medicine, remarkable.

Depression severity: GRID-Hamilton scores decreased from an average of 22.75 at baseline (indicating moderate-to-severe depression) to 8.25 at the five-year follow-up — a statistically significant reduction with a Cohen’s d effect size of 1.5 (P < .001). An effect size of 1.5 is considered very large by clinical standards.

Remission and response rates: At the five-year follow-up, 67% of participants showed clinical response and 67% were in complete remission from their depression — up slightly from the 58% remission rate at 12 months.

Anxiety: Significant decreases in baseline anxiety scores (Cohen’s d = 0.84; P < .001).

Functional impairment: Significant improvements in work functioning, social functioning, and family functioning (Cohen’s d = 1; P < .001).

Qualitative findings: Participants reported improved empathy, self-acceptance, and interpersonal relationships. They described a greater capacity for positive emotions and enthusiasm — even in periods when depressive symptoms returned.

The lead researcher, Dr. Davis, described the finding this way: “Five years later, most people continued to view this treatment as safe, meaningful, important, and something that catalyzed an ongoing betterment of their life.”

🔗 Authority Source: Depression Remission Endures 5 Years After Psilocybin Trial — Ohio State University News

Why This Is Different From Traditional Antidepressants

To appreciate the significance of these psilocybin depression long-term results, you need to understand what conventional antidepressant treatment looks like by comparison.

Standard antidepressants — SSRIs, SNRIs, and other daily medications — require daily dosing to maintain their effects. The moment you stop taking them, the pharmacological mechanism stops. Many patients find that antidepressants lose effectiveness over time, requiring dose increases or medication switches. Side effects are common and persistent. And a substantial proportion of patients with major depressive disorder — estimated at 30% — do not adequately respond to antidepressants at all.

The psilocybin depression long-term results show something categorically different: two doses of psilocybin, given years ago, produced effects that were not only maintained but in some respects continued to grow over a five-year period without any additional treatment for many participants.

Researchers propose that psilocybin therapy may trigger what they call “positive behavioral feedback loops” — helping people gain fresh perspectives and emotional insights that continue benefiting their lives long after the treatment ends. This enables the development of healthier habits, relationships, and ways of relating to difficult emotions that serve as natural buffers against depression’s return.

One participant described it this way: “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.”

This description — of a life rebuilt around connection and meaning — is not a pharmacological effect. It is the result of a profound shift in perspective that psilocybin appears to catalyze. This is the “reset hypothesis” in action: psilocybin may not be treating the symptoms of depression so much as triggering the neural reorganization that changes the conditions that generate those symptoms. This is also why the potential benefits of microdosing psilocybin — at sub-perceptual doses — are so interesting to researchers: if even low doses nudge some of these same neuroplastic mechanisms, the implications for ongoing mood support are significant.

What About the 33% Who Relapsed?

Honest reporting of psilocybin depression long-term results requires engaging with the full picture — including the participants who did relapse.

Approximately one-third of participants showed some return of depressive symptoms over the five-year follow-up period. Several important nuances are worth understanding about this finding:

Most used additional treatments: Only three of the 18 completing participants reported no depression-related treatment since the trial. Others had taken antidepressants, undergone psychotherapy, tried ketamine, or used psilocybin again — making it difficult to attribute the five-year outcomes solely to the original two-dose intervention.

Even relapsers reported improvement: Critically, even participants whose depression returned described their relationship to depression as fundamentally changed. They reported their depression as more situational and manageable — less tied to their identity, less interfering in their life — compared to how they experienced it before psilocybin-assisted therapy.

The conservative methodology: Dr. Davis took a deliberately conservative analytical approach — assuming the six participants who did not complete the five-year follow-up had experienced complete relapse back to their baseline depression severity. Even with this conservative assumption, the reduction in depression scores remained very large and statistically significant.

Sample size limitations: The study involved 18 completing participants — a small sample by clinical trial standards. Dr. Davis acknowledged this directly, stating there is still a lot to learn. The findings are directionally compelling but require replication in larger, more diverse populations before they can be considered definitive.

🔗 Authority Source: Five-Year Outcomes of Psilocybin-Assisted Therapy for MDD — Journal of Psychedelic Studies, 2025

What Made These Patients Eligible?

Understanding who participated in the original trial helps calibrate who these psilocybin depression long-term results may apply to.

Inclusion criteria for the original trial:

• Adults aged 21–75 with a confirmed MDD diagnosis
• Not currently using antidepressant medications at the time of the trial
• No history of psychotic disorder
• No history of serious suicide attempt or psychiatric hospitalization

This is an important distinction: these were not treatment-resistant depression patients (who have failed multiple medications). They were patients with MDD who were medication-free at enrollment. The psilocybin depression long-term results from this study may not directly translate to populations with treatment-resistant depression, though separate trials — including COMP360’s Phase III work — are specifically designed to evaluate that population.

The Psychotherapy Component: Non-Negotiable

A recurring theme in the discussion of these psilocybin depression long-term results is a question that the study’s design cannot definitively answer: was it the psilocybin, the psychotherapy, or the combination?

The original trial did not include a placebo group — all participants knew they were receiving psilocybin — which raises the possibility that expectation effects contributed to outcomes. The psychotherapy component was substantial: six to eight hours of preparatory meetings, two supervised dosing sessions, and follow-up integration sessions.

Dr. Davis has directly addressed this: the goal is not to understand whether psilocybin or psychotherapy produced the benefit, but to understand psilocybin-assisted therapy as a unified treatment modality in which both components are integral. Stripping either element out fundamentally changes what is being offered.

This is directly relevant to anyone considering psilocybin experiences outside of a clinical framework. The principles that make psilocybin-assisted therapy work — preparation, intentional set and setting, and post-experience integration — are the same principles covered in our Set & Setting Guide and our Harm Reduction Guide. The drug alone does not produce the healing. The experience, context, and integration do.

What These Results Mean for FDA Approval

The publication of compelling five-year psilocybin depression long-term results coincides with the most advanced regulatory moment in psilocybin’s clinical history.

Compass Therapeutics’ COMP360 completed its Phase III primary endpoint for treatment-resistant depression in late 2025, with a second confirmatory trial readout expected in H2 2026. If those results hold, it could become the first psilocybin formulation to enter the FDA approval process. Long-term follow-up data of the kind published by Ohio State and Johns Hopkins directly supports the safety and durability claims that any FDA approval pathway would require.

Separately, the expanding VA clinical trial network, Texas’ $50 million in ibogaine research funding, and the Congressional PATH Caucus are all creating the institutional infrastructure and political momentum that successful regulatory change requires. For the full context of psychedelic-assisted therapy access and cost in 2026, see our Psychedelic Therapy in 2026 guide. And for the full spectrum of psilocybin’s therapeutic applications, our Psilocybin for PTSD Veterans guide covers the emerging evidence for trauma treatment.

What These Results Mean for Patients With Depression Right Now

For the estimated 280 million people worldwide living with depression — and the 30% who have not responded adequately to conventional treatment — the psilocybin depression long-term results from this study offer something that has been in short supply: genuine hope backed by real data.

These results do not mean psilocybin is a universal cure for depression. They mean that for a meaningful proportion of patients, two carefully supported sessions can produce shifts in how they relate to their depression — and their lives — that persist and even grow over years. That is a finding unlike anything conventional psychiatric medicine has produced.

The path from these findings to widespread clinical access involves regulatory approvals, healthcare system integration, training of therapists, and resolution of ongoing questions about who is a good candidate and how many sessions are needed. None of that is simple or fast. But the direction of the evidence has never been clearer.

Frequently Asked Questions (FAQ)

Q: Did psilocybin cure depression permanently for these patients? Not permanently in all cases — approximately 33% showed some return of symptoms over five years. However, 67% were in clinical remission at five years, and even those whose depression returned described it as more manageable and less identity-defining than before treatment.

Q: How many sessions of psilocybin therapy were involved? Two doses of psilocybin, approximately two weeks apart, supported by approximately 13 hours of structured psychotherapy across preparation, dosing, and integration sessions.

Q: Were there any serious side effects over five years? Most participants reported no adverse events. Three reported unwanted effects (increased emotional sensitivity) and two reported negative effects related to the trial process (waitlist difficulties and medication weaning). No serious long-term adverse events were reported.

Q: Can I access psilocybin-assisted therapy for depression right now? In Oregon and Colorado, licensed psilocybin service centers offer supervised therapy. Compass Therapeutics’ COMP360 is in Phase III trials with a confirmatory readout expected H2 2026. Elsewhere in the US, access currently requires enrollment in a clinical trial.

Q: Does this mean I should stop my antidepressants and try psilocybin? Absolutely not without medical supervision. Never stop or change psychiatric medications without consulting your healthcare provider. The original trial participants were medication-free before enrollment for specific safety reasons related to drug interactions.

⚠️ Disclaimer: This article is for educational purposes only and does not constitute medical advice. If you are experiencing depression or considering changes to your treatment, always consult a qualified healthcare professional. Psilocybin remains a federally controlled substance in the United States.

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