Psychedelic therapy is having a cultural moment, and cultural moments are bad for clear thinking. Depending on which corner of the internet you're standing in, these medicines are either the salvation of psychiatry or an overhyped bubble about to burst. As someone who now offers ketamine-assisted psychotherapy in my own practice, and who watches Colorado's licensed psilocybin program operating a few miles from my office, I think the honest answer is more interesting than either story. I want to walk through what the research actually shows — including the parts the enthusiasts tend to skip.
Start with ketamine, because it has the deepest evidence base. In 2006, researchers at the National Institute of Mental Health published a randomized controlled trial showing something genuinely unusual: a single infusion of ketamine produced significant antidepressant effects in people with treatment-resistant depression within hours. Not the six weeks we expect from standard antidepressants — hours. That finding has been replicated many times since, and in 2019 the FDA approved esketamine, a nasal-spray form, for treatment-resistant depression. Whatever else is uncertain in this field, the basic rapid-acting antidepressant effect of ketamine is about as established as anything in psychiatry.
Here's the caveat the headlines skip: the effect fades. Without something more, the relief from ketamine alone tends to dissipate over days to weeks, which is why infusion clinics operate on repeat-treatment models. This is where the psychotherapy part of ketamine-assisted psychotherapy stops being decorative. A 2019 study published in the Journal of Psychoactive Drugs followed hundreds of patients receiving ketamine embedded in an actual psychotherapy process across three clinics, and found significant improvements in depression and anxiety — with the interesting detail that people with the heaviest symptom burdens often benefited most. The durability question is exactly why I hold the medicine inside the therapy rather than alongside it. If the effects fade when nothing changes, that's an argument for the therapy, not against the medicine.
"The medicine seems to open a window. What the research keeps suggesting is that the window matters less than what you build while it's open."
Psilocybin has the more dramatic recent history. In 2016, teams at Johns Hopkins and NYU published parallel trials in patients with cancer-related anxiety and depression, and the results were striking — large, rapid reductions in depression and anxiety, sustained at six-month follow-up for most participants, often traced by the participants themselves to a single session. Follow-up work has extended the picture: a 2021 trial in JAMA Psychiatry found large effects for major depressive disorder, and long-term follow-ups of the Hopkins participants have found a meaningful share still in remission years later.
But the honest ledger has entries on the other side. A 2021 trial in the New England Journal of Medicine compared psilocybin head-to-head with escitalopram — a standard SSRI — and on the primary outcome measure, psilocybin did not significantly beat the medication. A large 2022 trial of synthetic psilocybin for treatment-resistant depression showed real dose-dependent benefits, but with a meaningful minority of participants experiencing adverse events, including some serious ones. And MDMA-assisted therapy, which produced impressive phase 3 results for PTSD, was rejected by the FDA in 2024 over concerns about trial integrity — including the near-impossibility of keeping participants blind to whether they'd received a psychedelic.
That blinding problem deserves a moment, because it hangs over the whole field. In a standard drug trial, participants don't know if they got the medicine or the placebo. In a psychedelic trial, everyone knows within forty-five minutes. That means expectancy — the belief that you've received something transformative — is doing some unknowable portion of the work in every one of these studies. It doesn't erase the findings. It does mean the field's confidence should be more modest than its press coverage.
There are other honest limits. The trial populations have skewed white, educated, and self-selected — people who wanted a psychedelic experience and believed in it. The medicines are genuinely contraindicated for some people, including those with psychotic or manic vulnerability and certain cardiac conditions. And the studies all embedded the medicine in careful preparation and integration with trained clinicians — a structure very different from most real-world use.
So why do I offer this work at all? Because when I weigh all of it — the caveats included — what remains is still unusual. Effect sizes in the strong trials are larger than almost anything else in the mood-disorder literature. The rapid action matters enormously for people who have been suffering for years. And the mechanism that seems most plausible — a temporary loosening of rigid patterns, a window of heightened plasticity in which new meaning can actually take hold — aligns almost exactly with what depth-oriented therapy has always tried to do the slow way.
The medicine seems to open a window. What the research keeps suggesting is that the window matters less than what you build while it's open. That's a conclusion I can work with — carefully, honestly, and without pretending the open questions are closed.