In a basement lab at UC Davis, a rat sat in a tank of water. It had been given a dose of something that, on paper, looked a lot like DMT — the same molecule curanderos brew into ayahuasca and chemists call the most fast-acting psychedelic ever synthesized. The rat did not appear to be tripping. It was, however, growing new dendritic spines in its prefrontal cortex at a rate that would normally require electroconvulsive therapy or a month of ketamine infusions.

The compound was called tabernanthalog, or TBG. It had been engineered, atom by atom, to keep the dendrite-growing half of psychedelia and throw the hallucination half away. The chemist behind it was David E. Olson, who had come to UC Davis in 2015 from a postdoc at the Broad Institute studying HDAC inhibitors and spent the back half of the 2010s convincing the field that the trip and the cure were two separable things.

That argument is no longer just an argument. On October 28, 2025, the spinout Olson co-founded — Delix Therapeutics, now run by former Shire neuroscience chief Mark Rus — released Phase Ib data on its lead compound, zalsupindole. Eighteen adults with major depressive disorder saw their MADRS depression score drop by twelve points by Day 8, roughly a fifty-percent reduction, and stayed down through Day 36 — a month after the last dose. Across the full clinical program, more than 120 people have now received zalsupindole. Not one of them has reported a hallucination or a dissociative episode. Three weeks later, the FDA cleared a Phase II trial that allows patients to dose themselves at home, with no clinician chaperone and no Soothing Music Playlist. There is no precedent for that. Compass Pathways, the field’s most-watched psilocybin developer, has spent four years trying to get its drug through Phase III on the assumption that the trip itself is medically essential and must be supervised in a clinic for six to eight hours per dose. Delix is now arguing, with FDA agreement, that the trip is the side effect, not the cure.

That bet has shown up in the patent record before it has shown up in the press. A search of all 9.3M US utility grants for psychedelic compounds — psilocybin, DMT, mescaline, ibogaine, LSD, plus the new coinages “psychoplastogen” and “neuroplastogen” — returns six grants in 2020, 25 in 2023, and 39 in 2025. The shape of the curve is itself unsurprising; the post-2020 psychedelic patent rush is well-documented. What is surprising is what’s inside the recent ones. Through 2022, almost every grant in this set was about getting more psilocybin into a pill or stabilizing a tryptamine on a shelf. Starting in 2023, the language changes. The titles fill up with phrases that did not exist in pharma a decade ago: “non-hallucinogenic serotonin 5-HT2A receptor modulators,” “compounds for increasing neural plasticity,” “phenoxy and benzyloxy substituted psychoplastogens.” A field that started as a renaissance for the old molecules has quietly bifurcated into a hunt for new ones that work without them.

The most consequential of these grants issued on July 1, 2025. US patent 12,343,337, assigned to the Regents of the University of California, claims a method of treating depression by administering a non-hallucinogenic analog of dimethyltryptamine that, in the patent’s own language, “produces a maximum number of dendritic crossings with an increase of greater than 1.0 fold by a Sholl Analysis.” The Sholl analysis is the imaging technique neuroscientists use to count branches on a neuron the way a botanist counts branches on a tree. The patent asks the reader to imagine a depression drug whose label discloses, as the mechanism of action, a measurable increase in branchy-ness. Then comes the punchline. Claim 2 names the three explicit examples of the non-hallucinogenic DMT analog covered by the method: 6-methoxy-DMT, 6-fluoro-DMT, and rizatriptan.

Rizatriptan is Maxalt. It is a migraine pill Merck has been selling since the FDA approved it in 1998. Generics have been on the shelf for over a decade. Olson’s lab has been granted a patent that asserts an old, off-patent migraine drug — a 5-HT1B/1D agonist that pharmacists hand out at the rate of millions of prescriptions a year — is also, structurally, a non-hallucinogenic DMT analog that grows dendritic spines. The claim survived USPTO prosecution. If it survives whatever challenges are coming, it is one of the more interesting drug-repurposing footnotes of the decade.

The mechanism story behind these claims is starting to make sense. In a paper published August 4, 2025 in Nature Neuroscience, Olson’s group at UC Davis compared what 5-MeO-DMT and TBG actually do at the receptor where both bind: serotonin 2A. Both turned on cortical neuroplasticity. Only the psychedelic version triggered glutamate bursts and a cascade of immediate-early genes long thought to be the engine of plasticity itself. TBG grew the spines without the gene cascade and, by extension, without the trip. The way the field has come to talk about it — and the way zalsupindole’s preclinical paperwork describes its target engagement — is a partial agonist at 5-HT2A with an intrinsic efficacy of about 17 percent. Just enough activity to make the dendrites bloom. Not enough to set off the immediate-early cascade that, in humans, manifests as the wallpaper breathing.

The companies racing to claim this strip of mechanism are not just Delix. Kuleon Bioscience, a self-funded outfit operating out of Seattle’s Ballard neighborhood and previously called PsiloSterics, has accumulated five US grants in the past two years, all on small molecules its filings describe as “neuroplastogens” or biased serotonin receptor modulators. Kuleon says it screens its libraries with AI/ML in silico models against thousands of novel compounds, then patents the survivors. ATAI Therapeutics, the publicly-traded biotech, picked up its second grant in this slice of the field in August 2025. Mindset Pharma, Enveric Biosciences, CAAMTECH, and Compass Pathways’ Compass Pathfinder are filing in the same neighborhood. UC Davis Health committed its new IFM Fund’s first investment to Delix in September 2025, on top of the company’s existing $100M from RA Capital, Artis Ventures, and OMX, plus an $825,000 Department of Defense grant aimed at adapting a neuroplastogen for hearing loss.

Read the whole stack together and a real story emerges. The psychedelic-medicine industry that the press covered between 2020 and 2024 — Compass, MAPS, atai, Cybin, all running classical psychedelics through clinical trials — was the loud half. The other half was a wave of synthetic chemistry programs aimed at making the loud half obsolete. If the at-home Phase II of zalsupindole reads out the way the Phase Ib did, the question for an R&D director at a major pharma is no longer whether there is a market for psychedelic-derived neuroplasticity drugs. It is whether the future of that market involves any psychedelic experience at all, or whether the molecules will look more like a pill you take with breakfast on a Tuesday because your prefrontal cortex needs new wiring and the dose-response curve has been calibrated to grow it without ruining your day.

A migraine pill Merck launched the year Bill Clinton was impeached now sits inside a 2025 antidepressant patent claim. That is what an adjacent possible looks like when somebody finally builds the bridge across it.

Method note. Counts come from a search of the 9.3M US utility patent grants in our local USPTO mirror for the terms psilocybin, psilocin, psychedelic, “DMT treatment,” mescaline, ibogaine, tabernanthalog, “LSD treatment,” psychoplastogen, and neuroplastogen, joined to USPTO assignee records. Patent claim text quoted from US 12,343,337 (Regents of the University of California, granted July 1, 2025). Phase Ib trial figures, FDA Phase II clearance details, and the 120-person hallucination-event count are from Delix Therapeutics’ October 28, 2025 disclosure via Business Wire. Mechanism descriptions are drawn from the Olson lab’s August 2025 Nature Neuroscience paper and a 2025 PNAS paper on the LSD analog JRT, plus the public summary of zalsupindole’s pharmacology. UC Davis IFM Fund investment confirmed via UC Davis Health press release, September 2025. We did not query any private clinical-trial registry or company financials database; reported numbers are limited to what the companies and journals have themselves published.