Research timeline and gaps: Psychedelic Microdosing and Mental Health

Selected publication milestones, not an exhaustive history or discovery priority claim.

2018 — Intermittent rodent psilocin/ketamine anxiety-proxy study gives modest possible anxiogenic boundary rather than clinicalLSD evidence. Original PMID29537989.

2018 — Open-label microdose-event creativity tasks supply early quantitative exploratory support without placebo isolation. Original PMID30357434.

2019 — Controlled low-dose LSD alters interval timing without robust subjective effects; acute pharmacology becomes experimentally testable. Original PMID30478716.

2019 — Healthy acute dose-response study shows measurable subjective action while most cognition and mood outcomes remain unchanged. Original PMID31331617.

2019 — Six-week naturalistic tracking reports symptom declines and mainly dose-day changes, motivating controlled repeat-dose studies. Original PMID30726251.

2020 — Microdosing demographic/diagnosis survey identifies self-selection and concurrent-drug differences. Original PMID32108529.

2021 — Verified base-dose pharmacokinetics show5microgram subjective-null versus10/20microgram perception, defining a dose-dependent boundary. Original PMID32975835.

2021 — Citizen self-blinding separates randomized capsule exposure from guessed allocation and reports no accumulated between-group benefit. Original PMID33648632.

2021 — Prospective baseline expectations predict later wellbeing improvement, strengthening a competing explanation. Original PMID33479342.

2021 — Acute plasmaBDNF positive is reported; it remains a peripheral biomarker rather than validated treatment mediation. Original PMID33860175.

2022 — Repeated controlled10/20base-equivalent LSD produces subjective effects but no residual mood or cognitive advantage. Original PMID35106880.

2022 — Preregistered psilocybin microdose crossover is symptom-null with later blind breaking. Original PMID34915762.

2022 — Psilocybin mushroom microdose subjective recognition andEEG effects coexist with wellbeing/cognition nulls. Original PMID35918311.

2022 — Full-doseCOMP360TRDprimaryweek-three positive has dose and sustained-response limits distinct from microdosing. Original PMID36322843.

2023 — Six-week home LSD trial separates transient dose-day mood elevation from no persistent pre/post change. Original PMID36997080.

2024 — Restricted high-BDI acute low-dose crossover positive raises a symptomatic-population question without testing sustained treatment. Original PMID38042914.

2024 — Same home-trial wearable sleep analysis identifies a delayed measurable effect rather than clinical symptom efficacy. Original PMID38622150.

2025 — Two-center six-week ADHD clinical primary fails despite drug perception and measured allocation guesses. Original PMID40105807.

2025 — Same home-trial PK analysis finds no peripheralBDNF alteration, limiting uniform plasticity-marker claims. Original PMID40251818.

2025 — Positive-controlled chronic mouse cardiac study finds no observedLSD remodeling, with human rare/longterm risk unresolved. Original PMID41789300.

2026 — Direct eight-week open-label MDD improvement is published, furnishing exploratory clinical support requiring causal isolation. Original PMID41202873.

2026 — Same depressed-mood crossover reward analysis relates neural changes to48hour symptoms without mediator manipulation. Original PMID41529826.

2026 — Later effectively blinded psilocybin longitudinal trials report no corrected emotional/cognitive benefit. Original PMID41110634.

2026 — Pooled original truffle creativity trials retain a restricted guess-adjusted originality positive. Original PMID41187880.

2026 — Full-doseEPISODEprimaryresponse null preserves endpoint hierarchy despite favorable exploratory scales and safety signals. Original PMID41848690.

Research gaps

Complete outcome-paper methods, analyzed sample, missing-data handling, dose distribution and comparator/rater masking for the completed LSDDEP2 trial; additional independent symptomatic trials and anxiety-specific estimates.

Dose/base-tartrate normalization and individual perceptibility measured before declaring a regimen subperceptual.

Independent expectancy manipulation and safe interpretation of postdose allocation-guess adjustment.

Clinical relevance of reward/connectivity/EEG/BDNF signals rather than assumed plasticity-mediated therapy.

Longerterm, uncommon and cardiovascular harms; small trial echo/mouse nulls do not quantify rarehuman risk.

Regimen-specific comparative efficacy, support intensity and function without transferring full-dose/ketamine positives ornulls.

Boundary experiment

Registered symptomatic-MDD trial of titrated 5–20 microgram base-equivalentLSD twiceweekly for 8 weeks versus credible sensory-matched active comparator, with equalcontact/co-care and an expectancy-factor manipulation or prespecified sensitivity analyses; follow throughwithdrawal and relapse.