For years, one question has haunted psilocybin research: what happens after the glow fades?
The early results from psychedelic-assisted therapy have been striking, in some cases remarkable. Depression scores drop and people describe feeling like themselves again for the first time in years. But clinical trials are short by nature. They capture a only snapshot. Critics have rightly asked whether the benefits hold up over the months that follow, or whether they slowly dissolve back into the grey.
A new study published in Psychotherapy and Psychosomatics in May 2026 offers the most rigorous answer we have yet. The EPIsoDE trial, conducted across two German university hospitals, followed 126 people with treatment-resistant depression (TRD) for a full year after receiving psilocybin-assisted therapy. The conclusion? The antidepressant effects not only held, they were stable across the entire follow-up period, with no meaningful decline between the six-month and twelve-month marks.
The researchers are calling it the largest and most complete long-term follow-up of any clinical psychedelic trial ever conducted.
Who Was In This Trial, and Why Does It Matter?
Treatment-resistant depression is not ordinary depression. These are people who have typically tried five or more antidepressants across their lifetime and found no adequate relief. The average participant in this study had been living with major depression for nearly fourteen years. More than three quarters had at least one other psychiatric diagnosis alongside their depression. These are not people for whom recovery comes easily or often.
Participants received either one or two doses of 25mg psilocybin, embedded within a broader psychotherapy framework of seven sessions spanning preparation and integration. The controlled phase of the trial ended at twelve weeks. After that, participants were free to pursue other treatments, and researchers followed them at six and twelve months to see what happened.
The Numbers
At baseline, average depression scores on the Hamilton Rating Scale sat around 22, which falls in the moderate-to-severe range. By the six-month follow-up, scores had dropped by roughly eight points on average. By twelve months, they had dropped by roughly the same amount again. Depression scores were holding in the mild range.
What makes this particularly striking is that these improvements were not inflated by participants who had responded well and then received top-up treatments. The full cohort was included, initial non-responders and all, and no one received additional psilocybin doses during the follow-up period. The improvements appear to reflect durable change rather than ongoing pharmacological support.
Response rates, defined as at least a 50% reduction in depression scores, sat at 34% at six months and 37% at twelve months. A smaller subset, around 22% at six months, maintained sustained response from the end of the treatment phase all the way through.
The Unexpected Finding About Antidepressants
One of the most thought-provoking results involves conventional antidepressants. By twelve months, about a third of participants had restarted antidepressant medication. This group showed notably worse outcomes, scoring around four points higher on the depression scale than those who had not restarted.
The authors are careful not to overinterpret this. It is not that antidepressants caused worse outcomes. More plausibly, the people who restarted medication were those who had benefited least from psilocybin therapy, and were seeking additional help as a result. But the finding does suggest that the long-term benefits of psilocybin therapy appear to operate through a different mechanism than conventional pharmacotherapy – one that does not require ongoing chemical support once established.
What This Might Mean
The conventional model of treating depression, especially treatment-resistant depression, is essentially one of indefinite management. You find something that takes the edge off and you stay on it, indefinitely. The side effects become a permanent feature of your life alongside the condition itself.
What the EPIsoDE results gesture toward is a different model entirely. One or two sessions, carefully supported by psychotherapy, producing effects that persist and perhaps deepen over time without further pharmacological input. The authors describe this as potentially “salutogenic” or disease-modifying rather than merely symptom-suppressing. The brain, in other words, may not just be numbed but actually changed.
This framing fits well with what we know about neuroplasticity, the REBUS model of prediction error, and the deep restructuring of meaning-making that psychedelic experiences appear to catalyse. Psilocybin is an ecological disturbance, disrupting entrenched patterns and opening the soil for new growth.
The study has limitations. There was no control group in the follow-up phase. Most participants were white, highly educated, and German. The psychotherapy component was not experimentally varied, so we cannot cleanly separate its contribution from the psilocybin’s.
But within those limits, the signal is clear and consistent. For many people with treatment-resistant depression, a carefully supported psilocybin experience can produce clinically meaningful relief that lasts. This is truly revolutionary in a field where healing is rare.
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