Postpartum depression affects roughly one in five new mothers globally. Up to 30% of those diagnosed are still symptomatic two years after giving birth. And the current treatment landscape (SSRIs that take four to six weeks to work and a single FDA-approved option requiring a two-week dosing course) leaves an enormous amount of suffering unaddressed.
A new phase 2a clinical trial just published in the Journal of Clinical Psychiatry may represent one of the most striking early signals in this space in years. Researchers administered inhaled mebufotenin (5-MeO-DMT, formulated as GH001) to ten women with moderate-to-severe postpartum depression. By day eight, every single patient was in remission.
What the study did
The trial, sponsored by GH Research and conducted at sites in the UK and the Netherlands, enrolled women aged 18 to 45 who met diagnostic criteria for major depressive disorder with peripartum onset and had Montgomery-Asberg Depression Rating Scale (MADRS) scores of 28 or above at baseline, reflecting moderate to severe symptoms. The mean baseline score was 36.7.
GH001 was administered as an individualised dosing regimen of up to three escalating doses (6mg, 12mg, and 18mg) on a single day, using an inhalation device that delivers a vaporised aerosol. The entire psychoactive window for each dose lasted roughly 20 to 25 minutes. Patients were supervised by qualified healthcare professionals but received no planned psychotherapy before, during, or after dosing.
The results
The primary endpoint was change in MADRS total score from baseline to day 8. The mean reduction was 35.4 points, corresponding to approximately 96% symptom reduction. All ten patients achieved both response (50% or greater reduction) and remission (MADRS score of 10 or below) by day 8. Crucially, these effects were already present just two hours after the final dose on day 1 and were maintained through the end of the trial.
Improvements extended beyond depression scores. The Clinical Global Impression scale showed near-complete resolution of illness severity. The Barkin Index of Maternal Functioning, which assesses a mother’s ability to care for herself and her infant, improved by approximately 56%. Suicidal ideation, present in three patients at baseline, dropped to zero by discharge on day one and remained there.
On safety, there were no serious adverse events. The most commonly reported side effect was headache, affecting five of ten patients. Transient increases in blood pressure and heart rate were observed during the psychoactive phase, consistent with other psychedelic compounds, and resolved within 20 to 60 minutes. No sedative effects carried over after the experience ended, and all patients were deemed ready for discharge on the same day.
For the four patients who were still lactating, the researchers measured mebufotenin and its metabolites in breast milk. Levels were detectable at one hour post-dose but declined to below or near the limit of quantification by around eight hours, and were undetectable on days 2 and 8. This suggests that a brief interruption of breastfeeding around the dosing window may be sufficient.
What makes this different
To understand why these findings are significant, it helps to compare them against the existing landscape. SSRIs, the established first-line treatment, typically require four to six weeks to show meaningful effect and carry chronic side effect profiles that contribute to poor adherence.
Zuranolone, the only FDA-approved treatment specifically for PPD, requires a 14-day oral dosing course, comes with driving restrictions after each dose, and sees comparatively low clinical uptake. Brexanolone, which was previously approved but has since been withdrawn, required a 60-hour intravenous infusion in a clinical setting.
GH001 achieved remission in all patients within hours, on a single day, in an outpatient setting, with same-day discharge.
Mechanistically, mebufotenin acts as a nonselective serotonin agonist with a particularly strong affinity for the 5-HT1A receptor (rather than the 5-HT2A receptor more associated with classical psychedelics like psilocybin). Its plasma half-life is short, which likely accounts for the compressed duration of psychoactive effects and the clean safety profile post-experience. The researchers suggest the rapid antidepressant effects may be linked to downstream glutamatergic signalling and the promotion of acute neuroplasticity, though the precise mechanisms remain an open question.
What is 5-MeO-DMT?
5-MeO-DMT (mebufotenin) is a naturally occurring psychoactive compound found in several plant species and, most famously, the secretions of the Sonoran Desert toad (Bufo alvarius). Unlike psilocybin, which produces a prolonged multi-hour experience, 5-MeO-DMT is characterised by an intense but extremely short-lived altered state, typically lasting 15 to 45 minutes. It acts primarily on serotonin receptors, with a particularly strong affinity for 5-HT1A, and appears to drive rapid changes in neural plasticity rather than the extended perceptual shifts associated with classical psychedelics.
Interest in its therapeutic potential has been growing steadily, and it recently attracted mainstream attention when biohacker and longevity experimenter Bryan Johnson publicly documented his own 5-MeO-DMT experience, describing significant shifts in mood and cognitive state in the days following. Johnson’s experiment was self-directed and anecdotal, but it brought wider visibility to a compound that researchers had been quietly investigating for years.
GH001 is a synthetic, pharmaceutical-grade inhalation formulation of 5-MeO-DMT, removing the variability and ethical concerns associated with toad-derived sources.
Important caveats
This is a small, open-label, uncontrolled pilot trial of ten participants with no placebo group. It was also a predominantly white sample (90%), with a follow-up window of just one week. The absence of a control group makes it difficult to separate treatment effects from expectancy, natural recovery, or regression to the mean, though the speed and magnitude of response make purely placebo-driven effects implausible.
The researchers had originally aimed to enrol fifteen patients but stopped early due to recruitment challenges, driven in part by strict inclusion criteria that excluded women on concurrent antidepressants or with significant psychiatric comorbidities.
What this study does, convincingly, is establish a proof-of-concept signal strong enough to justify the next stage of investigation. Placebo-controlled trials with longer follow-up are needed, and the authors acknowledge this explicitly. The maternal functioning data also opens a genuinely important question about whether this kind of intervention could affect the mother-infant relationship in measurable ways.
The picture emerging here is of a compound that acts fast, clears quickly, and may fundamentally change the conversation about how postpartum depression is treated. That conversation is just beginning.
Since publishing this article, The Spore Report has been contacted by members of the UK psychedelic facilitator community who submitted formal concerns to the Health Research Authority prior to this trial. Their objections centre on the administration of a powerful psychedelic to severely depressed, potentially psychedelic-naive new mothers with limited preparation and minimal integration support, and whether informed consent could adequately reflect those risks. Questions have also been raised about GH Research’s investor overlap with Lusaris, a US biotech that ran a comparable no-support 5-MeO-DMT trial, quietly collapsed under unexplained circumstances, and was backed by the same private equity firm. We are continuing to investigate and will update this piece accordingly. If you have direct knowledge of GH Research’s trials, please contact us at team@mushies.co.uk.
We are so happy to hear that this simple study helped these women so profoundly! This truly is wonderful news and another huge confirmation that this medicine works!
We see it working in our live and the lives of the people we serve and it continues to be the gift that keeps on giving. Thank you Bufo! And thank you to the people who organized this study.