Seven Decades, One Bibliography: What 70 Years of Animal Psychedelic Research Actually Contains — and What It Leaves Out
Photo: Joe Haupt from USA, CC BY-SA 2.0, via Wikimedia Commons
The prevailing assumption inside psychedelic science is that the animal research base is vast — decades of rodent work, primate studies, enough citations to fill a tenure file. When we set out to test that assumption, we found something more complicated. The corpus is real, but it is far smaller, far narrower, and far more institutionally concentrated than the field's confidence would suggest.
Building the Corpus
We assembled the dataset through structured searches of PubMed, Scopus, and Web of Science, using compound names (LSD, psilocybin, DMT, 5-MeO-DMT, ibogaine, mescaline, MDMA, and their analogs) crossed with animal-subject terms, supplemented by backward citation chaining from key reviews. After deduplication and screening — excluding human trials, in vitro work, and studies where the psychedelic compound was merely a comparison ligand — the final corpus stood at roughly 2,400 studies spanning 1955 to the present.
That number surprised us. For a seventy-year research program that helped define modern neuropsychopharmacology, it is remarkably thin. Compare it to the antidepressant literature, where animal studies number in the tens of thousands. Psychedelic animal research has always been a boutique enterprise, punctuated by booms and long fallow periods.
The Shape of the Record
The temporal distribution tells its own story. Publication volume climbed through the late 1950s and 1960s, collapsed after the 1970 Controlled Substances Act made scheduling and supply a bureaucratic obstacle course, and did not recover until the mid-2010s renaissance. That fifty-year trough is not just a historical curiosity — it means an entire generation of methodological development happened in a vacuum, and much of the pre-1970 work was conducted under standards (sample sizes, randomization, blinding, welfare oversight) that would not survive modern IACUC scrutiny.
Species distribution is even more skewed. Rats and mice account for approximately 70 percent of the corpus. Non-human primates, concentrated in the 1960s and in a handful of federally supported primate centers, make up most of the remainder. Dogs — the species American veterinarians will actually encounter in clinical practice — appear in a scattering of mid-century behavioral studies and almost nothing since. Cats, once a mainstay of serotonin pharmacology work, have effectively vanished from the record. Birds, reptiles, fish, and invertebrates are statistical rounding errors.
The Funding Fingerprint
Coded funding sources reveal the field's dependency structure. Pre-1970, support came disproportionately from federal agencies with clinical or defense interests. The post-2015 revival is bankrolled almost entirely by private philanthropy and a small cluster of commercial entities with direct financial stakes in drug approval. Very few grants in the corpus come from agencies without a product pipeline in play. For veterinary researchers, that matters: the questions funders find interesting — efficacy endpoints translatable to human therapeutics — are not the questions a clinician managing a household exposure, a barn contamination, or a zoological collection needs answered.
What the Gaps Mean for Veterinary Science
Three gaps deserve particular attention from our readership.
Domestic species toxicology. The pharmacokinetics of psilocybin, DMT, and related tryptamines in dogs and horses are essentially uncharacterized. Everything a practitioner knows about dosing thresholds and toxicity is extrapolated from rodents and humans — a leap the comparative literature does not support.
Non-mammalian welfare. If entheogenic compounds are moving through ecosystems — through backyard gardens, feed contamination, or wildlife scavenging — the receptor biology of birds, reptiles, and fish becomes relevant. The corpus has almost nothing to say.
Methodological quality. A substantial share of the pre-1990 studies lack the controls that modern systematic reviews demand. Treating this literature as settled science, as some popular psychedelic writing does, is indefensible.
A Working Bibliography
The annotated bibliography accompanying this article — organized by compound, species, decade, and study design — is available through the site's research resources page. It is intended as infrastructure: a starting point for veterinary students, IACUC reviewers, and clinicians who need to know what the evidence base actually contains before they make claims about it.
The lesson of seventy years of animal psychedelic research is not that we know a great deal. It is that we know a great deal about a very small slice of the animal kingdom, funded by a very small slice of the funding world, and that the species most relevant to American veterinary practice were studied briefly, long ago, and then abandoned. Filling those gaps is not a psychedelic-science priority. It is a veterinary one.
