Biological psychiatry
September 15, 2023
Robin J Murphy, Rachael Sumner, William Evans et al.
69 citations
Microdosing LSD (10 μg every three days for six weeks) in healthy adult men produced transient improvements in creativity, connectedness, energy, happiness, irritability, and wellness on dose days compared with nondose days, even after controlling for preintervention expectancy. However, no enduring changes in overall mood or cognition were observed between baseline and six-week assessments. The most notable adverse event was treatment-related anxiety, which led four participants in the LSD group to withdraw. Microdosing appears relatively safe in this population but does not support claims of lasting mood or cognitive benefits.
Journal of psychopharmacology (Oxford, England)
August 1, 2021
Rachael L Sumner, Emme Chacko, Rebecca McMillan et al.
68 citations
Ketamine, given at 0.44 mg/kg to 32 volunteers with major depressive disorder in a crossover design with the active-placebo remifentanil, produced psychedelic experiences that correlated with greater antidepressant response at 24 hours. Specifically, higher scores on spirituality, experience of unity, and insight were linked to larger reductions in depression ratings. Qualitative interviews revealed perceptual changes, loss of control, emotional shifts, a psychedelic afterglow, and lasting changes in perspective on life, people, problems, and depression. The findings suggest the psychedelic experience and afterglow contribute to ketamine's antidepressant effects, and that standard questionnaires may not fully capture these properties.
Pilot and feasibility studies
October 5, 2023
Carina Joy Donegan, Dimitri Daldegan-Bueno, Rachael Sumner et al.
23 citations
An estimated 260 million people worldwide have depression, and many self-treat with microdoses of psychedelics like LSD and psilocybin despite limited clinical evidence. A prior phase 1 study in healthy volunteers found LSD microdosing safe, well tolerated, and feasible with good adherence. This open-label pilot trial (LSDDEP1) will test tolerability and feasibility of an 8-week LSD microdosing regimen in 20 patients with major depressive disorder. Participants receive a sublingual LSD formulation (MB-22001) twice weekly at 5–15 µg. Tolerability is measured by withdrawal due to adverse events; feasibility by clinic visit attendance. Antidepressant response will be assessed with MADRS scores over 8 weeks. Results will inform a future randomized controlled trial.
Trials
April 23, 2021
Robin J. Murphy, Rachael L. Sumner, William J. Evans et al.
23 citations
A proposed study will test whether regular low doses of LSD, known as microdosing, produce the cognitive and emotional benefits reported anecdotally. Eighty healthy men will receive either a placebo or 10 micrograms of LSD every third day for six weeks. The study will measure personality, creativity, mood, cognition, brain plasticity, and brain imaging at baseline and after the protocol, with additional acute measures after the first dose. Daily functioning will be tracked via questionnaires and a wearable device. The goal is to rigorously evaluate microdosing claims using objective measures, with potential future applications for treating depression, addiction, and other conditions.
Trials
August 24, 2024
Dimitri Daldegan-Bueno, Carina Joy Donegan, Anna Forsyth et al.
14 citations
A phase 2b randomized controlled trial will test whether repeated low doses of LSD (4 to 20 micrograms, taken twice weekly for 8 weeks at home) reduce depressive symptoms in people with major depressive disorder, compared to an active placebo. The trial is triple-blind and includes measures of mood, personality, sleep, brain activity, blood biomarkers, and safety. This is the first controlled trial to test microdosed LSD in patients' natural environment. Results will help determine whether psychedelic microdosing is a viable additional treatment for depression and guide future research.
Neuropharmacology
November 5, 2025
Dimitri Daldegan‐bueno, C Donegan, Rachael L. Sumner et al.
4 citations
In an open-label phase 2A trial, 19 participants with major depressive disorder, most of whom were taking antidepressants, took microdoses of LSD twice weekly for eight weeks. No serious adverse events occurred, and one participant withdrew due to anxiety. Depression scores on the Montgomery-Åsberg Depression Rating Scale dropped by 59.5% at the end of the intervention, with improvements sustained for up to six months. Anxiety, rumination, stress, and quality of life also improved. The results provide preliminary evidence that microdosed LSD is safe and feasible for treating moderate depression, but randomized controlled trials are needed.
Drug Science Policy and Law
January 1, 2026
Sam Lasham, Rhys Ponton
1 citation
Drug control laws introduced since the early twentieth century reduce non-medical use and drug-associated harm but unjustly impact medical care and research. Restrictions on controlled drugs and prohibited plants in New Zealand, such as those under the Misuse of Drugs Act 1975, have limited clinical research on substances like MDMA, LSD, psilocybin, and DMT for decades. Beyond clinical applications, these legal restrictions also severely inhibit non-clinical research, as illustrated by the Act's impedance of research on mushroom-forming fungi in New Zealand.
Journal of chromatographic science
November 15, 2025
Mahima Bansal, Estelle Miller, Rachael Sumner et al.
A new high-performance liquid chromatography method accurately measures LSD and separates it from its degradation product iso-LSD. Validated according to international guidelines, the method works even when LSD is exposed to stress conditions that cause breakdown. Applied to illicit microdosing samples from a New Zealand drug checking service, the analysis found a significant discrepancy between users' estimated doses and actual LSD levels. This highlights risks for people using non-pharmaceutical microdosing preparations and underscores the need for reliable quality control to ensure safety.