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Home/Research/Placebo/Healthy Volunteers

Placebo for Healthy Volunteers

33 papers and 154 clinical trials exploring placebo as a treatment for healthy volunteers.

CompoundComparator / Control

Placebo

Placebo is the most widely referenced comparator in psychedelic clinical research, appearing in over 500 trials. Understanding how placebos are designed, administered, and interpreted is essential to evaluating the evidence base for psychedelic-assisted therapies — and one of the field’s most contested methodological challenges.

Full Placebo profile
IndicationApproximately 300 million people affected by depression worldwide.

Healthy Volunteers

Research involving healthy volunteers has expanded to investigate the therapeutic potentials of various psychedelics for mental health conditions. Recent findings, emphasizing compounds like psilocybin and DMT, illustrate a promising future for psychedelic-assisted therapies.

Full Healthy Volunteers profile

Academic Research

33 papers
Open Accessindividual

Comparison of acute effects of 3,4-methylenedioxymethamphetamine (MDMA) with and without a supplemental booster dose in healthy participants: a double-blind, randomized, placebo-controlled, crossover study

This double-blind, randomised, placebo-controlled crossover study (n=25) in healthy volunteers found that a 60 mg MDMA booster dose given 2 hours after 120 mg MDMA prolonged the subjective drug effects, but did not increase peak effects. Adverse effects were more common after both MDMA conditions than after placebo.

Published
June 4, 2026
Journal
Translational Psychiatry
Authors
Humbert-Droz, M., Becker, A. M., Valenta, J., Rudin, D., Luethi, D., Vukalovic, I., Eckert, A., Liechti, M. E., Mueller, L.
Open Accessindividual

Tripping on context: Characteristics and predictors of placebo and nocebo psychedelic effects

This pre-registered experiment (n=78) found that simply presenting inert air as nitrous oxide increased reported altered states of consciousness, ego dissolution, dissociation and side effects in healthy volunteers, although it did not change time perception. The placebo-like psychedelic effects were linked to greater responsiveness to verbal suggestion and absorption.

Published
June 2, 2026
Journal
MedRvix
Authors
Stein, M. V., Butler, M., Chapman, S., Deeley, Q., Terhune, D. B.
Open Accessindividual

EXPRESS: Global Increases in Brain Glucose Metabolism Following Acute N,N-Dimethyltryptamine and Harmine Administration in Healthy Volunteers: A randomised [F]FDG-PET Study

This re-analysis of a randomised crossover study (n=14) in healthy men found that buccal DMT plus harmine (pharmahuasca) increased brain glucose metabolism compared with placebo, with widespread rises across the cortex, especially in higher-order networks. The increase was linked to harmine levels, but not to DMT levels or to how intense the experience felt.

Published
June 1, 2026
Journal
Journal of Cerebral Blood Flow and Metabolism
Authors
Egger, K., Bozsak, R., Aicher, H. D. D., Sari, H., Poetzsch, S. N., Rominger, A., Martin-Soelch, C., Smallridge, J. W., Dornbierer, D., Quednow, B. B., Scheidegger, M., Cumming, P.
Open Accessindividual

LSD Relaxes Structural Constraints on Brain Dynamics: A Connectome Harmonic MEG Study

This re-analysis of a brain imaging study (n=17) used magnetoencephalography (MEG) in people given LSD or placebo and found that LSD loosened the usual link between brain structure and low-frequency activity, while gamma activity changed in a more selective way. Changes in default-mode network regions were linked to stronger feelings of ego dissolution.

Published
May 29, 2026
Journal
Biorxiv
Authors
Subramani, V., Pascarella, A., Brunel, J., Harel, Y., Muthukumaraswamy, S., Carhart-Harris, R., Jerbi, K., Lioi, G., Farrugia, N.
Open Accessindividual

Blinding integrity in psychedelic research: Evidence from a comparative randomized controlled trial of psilocybin, MDMA, and methylphenidate in healthy volunteers

This double-blind randomised controlled trial (n=120) in healthy volunteers assessed how well blinding held when people received psilocybin, MDMA, or methylphenidate as an active placebo, and found blinding was generally insufficient. Functional unblinding was highest for psilocybin, moderate for MDMA, and lowest for methylphenidate.

Published
May 28, 2026
Journal
European Neuropsychopharmacology
Authors
Belinger, L., Rieser, N., Engeli, E., Becciolini, L., Clamote, M., Pribis, M., Saissi, F., Florineth, G., Hehl, N., Herdener, M., Preller, K.
Open Accessindividual

DMT, Madness, and Healing: Psychosis Model, Therapy Model, and Their Relations to Mystical Experiences and Positive Emotionality

This randomised, placebo-controlled, double-blind crossover study (n=25) found that DMT (60 mg) increased psychotic-like experiences and suggestibility in healthy volunteers, alongside strong mystical and other psychedelic effects. The links between these effects appeared to be driven more by positive emotionality than by mystical experience alone.

Published
May 20, 2026
Journal
Research Square
Authors
Wießner, I., Falchi-Carvalho, M., Laborde, S., Barros, H., Bolcont, R., Medina, M., Mograbi, D., Coelho, N. G., Palhano-Fontes, F., Araujo, D.

Clinical Trials

154 trials
Not yet recruitingPhase I

The Effects of Psilocybin in Healthy Volunteers: Psychological, Biochemical and Electrophysiological Biomarkers.

This Phase I, randomized, triple-blind, parallel-group trial (n=50) will study the effects of a single 25 mg oral dose of psilocybin versus placebo in healthy adult volunteers aged 21–65, with the primary aim of characterising biological, psychological and high-density EEG (hd-EEG) biomarkers and related safety/tolerability following one-time administration. Participants will be randomised to receive either psilocybin 25 mg (one tablet by mouth) or a matching inactive placebo; the psilocybin is supplied by Filament Health (Burnaby, British Columbia). Key eligibility includes ages 21–65, BMI 18–34 kg/m2, no current or past substance use disorder, limited prior psychedelic exposure (never or at most one prior classic serotonergic psychedelic experience more than 5 years earlier), and contraception/pregnancy requirements for women of childbearing potential. Primary biochemical outcomes measured from baseline to 7 days post-dose include 2 AG (pmol/mL), 2 OG (pmol/mL), AEA (pmol/mL), OEA (pmol/mL), PEA (pmol/mL), Trp (μg/mL), Kyn (ng/mL), Kyn/Trp*1000 and 5 HT (ng/mL); psychological and hd-EEG measures will also be assessed. The study is scheduled to start 2026-09-01 with estimated completion 2029-09-01.

Started
September 1, 2026
Type
interventional
Blinding
triple
Randomized
Yes
Registry ID
NCT07433452
Not yet recruitingPhase II

Investigating the Analgesic Potential of (2R,6R)-HNK in Acute Pain in Healthy Volunteers

This Phase II, randomised, double-blind, placebo-controlled crossover trial (n=92) will evaluate the analgesic potential of a single intravenous infusion of (2R,6R)-hydroxynorketamine (HNK) in healthy adults aged 18 to 60 years. The study will assess whether 0.5 mg/kg HNK reduces acute experimental pain during quantitative sensory testing (QST) and will also examine pain-related and emotion-related brain responses. Participants will receive HNK or matched placebo as a single intravenous infusion over approximately 40 minutes, with visits repeated 1 to 3 weeks apart in the treatment group. A no-treatment control arm is included to help estimate natural changes and placebo effects. Pain ratings, blood draws, and functional MRI assessments will be repeated before and after infusion, including follow-up measures immediately after treatment, at 4 to 5 hours, and one day later. The trial will also compare placebo with the no-treatment group to gauge placebo analgesia.

Started
June 15, 2026
Type
interventional
Blinding
quadruple
Randomized
Yes
Registry ID
NCT07504601
Not yet recruitingPhase I

Psilocybin Administration With 5-HT1a Blockade

This early Phase I, randomised, triple-blind, crossover trial (n=18) will evaluate whether 5-HT1A receptor blockade alters the acute subjective effects of psilocybin in healthy volunteers. Participants will receive psilocybin with either pindolol or placebo, with the study focused on subjective survey outcomes, acute electroencephalography (EEG), and the mechanistic basis of the altered state of consciousness induced by psilocybin. In each dosing session, participants will be given a moderate dose of psilocybin trihydrate 18 mg (equivalent to 15 mg psilocybin anhydrate) together with pindolol 30 mg or a microcrystalline cellulose placebo. The study will also examine post-acute sleep and dreaming using sleep EEG, sleep diaries, and dream diaries, collected for 10 days before and 10 days after each drug administration session, alongside at-home sleep EEG recordings for 5 days before and 5 days after each session. The primary outcome is the Mystical Experiences Questionnaire, assessed from the first dosing session to the end of the second dosing session, over approximately 10 days.

Started
June 15, 2026
Type
interventional
Blinding
triple
Randomized
Yes
Registry ID
NCT07565493
Not yet recruitingPhase I

Consciousness and Psilocybin Effects on Well-Being: The CoPEWell Study

This Phase I, randomised, double‑blind, parallel trial (n=120) will evaluate whether intravenous psilocybin improves wellbeing when administered while awake versus while asleep, and whether psilocybin given during sleep differs from saline placebo, in healthy adults aged 18–45 with sub‑optimal self‑reported wellbeing. The primary outcome is change in Warwick–Edinburgh Mental Wellbeing Scale (WEMWBS) score from baseline (Day 0) to post‑dosing Day 29. Participants are randomised to one of three overnight dosing arms: psilocybin while awake with saline while asleep; saline while awake with psilocybin while asleep; or saline while awake with saline while asleep. Psilocybin is given intravenously as an infusion of 3.2 mg over 10 minutes followed by 0.8 mg over the next 20 minutes; placebo is 20 mL saline drawn into a 30 mL syringe. All participants receive 0.2 mg oral clonidine 60 minutes prior to the initial infusion to support sleep. Key secondary outcomes include psychological flexibility, social connectedness and measures of wellbeing, life satisfaction, purpose and meaning ascribed to the intervention, and participants can expect to be on study for up to 4 months.

Started
April 1, 2026
Type
interventional
Blinding
double
Randomized
Yes
Registry ID
NCT07360301
RecruitingPhase I

Acute Effects of Intravenous 5-MeO-DMT in Healthy Participants

This Phase I, randomised, quadruple-masked, placebo-controlled, parallel trial (n=40) will assess the acute subjective, physiological and pharmacokinetic effects of intravenous 5-MeO-DMT in healthy adult participants. The study compares single ascending infusion rates of 5-MeO-DMT (0.2, 0.4, 0.6, 0.8 mg/min administered intravenously over 30 minutes) against a saline placebo, with the primary focus on change in subjective effects over time. Participants aged 25–65 who meet eligibility criteria will attend three on-site visits over approximately two weeks (screening, study drug administration, and a follow-up about one week later). Participants are randomised to one of four active dose arms or placebo and are blinded to assignment. During the administration visit blood pressure and heart rate are monitored regularly, blood samples are collected via an intravenous catheter for pharmacokinetic analyses, and subjective effect scales are completed repeatedly from 1 hour 5 minutes before dosing to multiple time points after dosing (assessment window up to 245 minutes, including timepoints up to 180 minutes post-dosing). Key exclusions include current or past major psychiatric disorder, certain cardiovascular conditions, recent heavy hallucinogen use, pregnancy or breastfeeding, and other standard safety-related criteria.

Started
March 31, 2026
Type
interventional
Blinding
quadruple
Randomized
Yes
Registry ID
NCT07444788
RecruitingPhase I

Acute Analgesic Effects of MDMA on Experimentally Induced Acute Pain, Hyperalgesia and Allodynia in Healthy Participants

This Phase I, randomised, triple-masked, crossover trial (n=20) will assess the acute analgesic effects of oral MDMA in healthy adults aged 18 to 75 years. It will compare MDMA 25 mg, 75 mg and 125 mg with placebo to evaluate whether MDMA reduces experimentally induced acute nociceptive pain, hyperalgesia and allodynia. Participants will receive the study drug by mouth during a validated electrical stimulation pain model in which repeated small electrical pulses are applied under the skin to produce moderate pain and secondary pain phenomena. The main outcome is periprocedural pain measured with the numerical rating scale, with the highest MDMA dose compared against the lower doses and placebo.

Started
March 9, 2026
Type
interventional
Blinding
triple
Randomized
Yes
Registry ID
NCT07494214

Explore further

Search all Placebo papers Search all Healthy Volunteers trials Full Placebo profile Full Healthy Volunteers profile