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Home/Research/Placebo/Neurocognitive Disorders

Placebo for Neurocognitive Disorders

4 papers and 15 clinical trials exploring placebo as a treatment for neurocognitive disorders.

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
Indication55M+ people living with dementia worldwide

Neurocognitive Disorders

Neurocognitive disorders, including dementia, Alzheimer's disease, Parkinson's disease and traumatic brain injury, involve a progressive decline in memory, thinking and everyday function. Interest in psychedelics here rests on a strong biological rationale and early human safety signals, not on proven treatment: no completed controlled trial yet shows that psychedelics treat dementia or restore lost cognition.

Full Neurocognitive Disorders profile

Academic Research

4 papers
Open Accessindividual

Cross-Species Evidence for Psilocin-Induced Visual Distortions: Apparent Motion Is Perceived by Both Humans and Rats

This cross-species experimental study (n=21 humans; n=10 rats) finds that psilocin (18.2mg/70kg for humans; 0.3mg/kg for rats) impairs the ability to distinguish between static and moving images in both humans and rats. In humans, the impairment aligns with psilocin plasma levels and self-reported hallucination intensity. In rats, the effect is specific to motion perception, providing the first evidence of psilocin-induced visual distortions across species.

Published
September 1, 2025
Journal
Biological Psychiatry
Authors
Vejmola, C., Šíchová, K., Syrová, K., Janečková, L., Koudelka, V., Tesař, M., Nikolič, M., Viktorin, V., Viktorinová, M., Tylš, F., Korčák, J., Kelemen, E., Nekovářová, T., Brunovský, M., Horáček, J., Kuchař, M., Páleníček, T.
Open Accessindividual

DMT micro-phenomenology

Using micro-phenomenological interviews with 23 participants who received DMT during fMRI, the study shows DMT reliably produces deeply immersive presence experiences that unfold through a characteristic layering—initial multisensory effects followed by spatial, self-related and social reconfigurations. This structural and temporal mapping extends beyond concepts like ego dissolution to advance understanding of DMT's effects and the architecture of conscious experience, and demonstrates the value of systematic first‑person methods for comparing altered states.

Published
December 29, 2024
Journal
Preprints
Authors
Sanders, J. W., Milliere, R., Daily, Z. G., Carhart-Harris, R., Timmermann, C.
Open Accessindividual

Safety and cognitive pharmacodynamics following dose escalations with 3-methylmethcathinone (3-MMC): a first in human, designer drug study

In a first‑in‑human, placebo‑controlled crossover study in 14 volunteers, escalating low–moderate doses (25–100 mg) of 3‑MMC produced dose‑dependent but clinically modest increases in heart rate and blood pressure, transient psychostimulant and mild psychotomimetic effects, and improved performance across processing speed, cognitive flexibility, attention, memory and psychomotor tasks without impairing impulse control. The authors conclude that these low–moderate doses were well tolerated and pharmacodynamically resemble amphetamine‑type stimulants, with potential health risks likely to arise only at high or excessive doses.

Published
December 24, 2024
Journal
Neuropsychopharmacology
Authors
Ramaekers, J. G., Reckweg, J., Mason, N. L., Kuypers, K. P. C., Toennes, S. W., Theunissen, E. L.
Paywallmeta

The impact of psychedelics on patients with alcohol use disorder: a systematic review with meta-analysis

This systematic review and meta-analysis (s=6; 2023) assessed the role of psychedelics in treating alcoholism (AUD). LSD and any psychedelic therapy showed enhanced odds of achieving abstinence or reducing alcohol consumption in randomised, double-blind, placebo-controlled trials. However, the study highlights methodological weaknesses in the literature. It suggests that while promising, definitive statements about the value of psychedelics in treating AUD are precluded, emphasizing the need for future trials with greater rigour.

Published
December 18, 2023
Journal
Current Medical Research and Opinion
Authors
Sicignano, D., Hernandez, A. V., Schiff, B., Elmahy, N., White, C. M.

Clinical Trials

15 trials
Not yet recruitingPhase NA

Intranasal Dexmedetomidine-Esketamine for Sleep and Cognition in Older Adults With Mild-to-Moderate Cognitive Impairment

This randomised, double-blind, placebo-controlled trial (n=60) will assess whether an intranasal dexmedetomidine-esketamine combination improves sleep quality and cognitive function in older adults aged 60 years and above with mild-to-moderate cognitive impairment and comorbid sleep disorder. The main aim is to evaluate change in Pittsburgh Sleep Quality Index (PSQI) score 1 month after the intervention. Participants will receive either the dexmedetomidine-esketamine nasal spray, calculated at approximately 0.4 μg/kg of dexmedetomidine plus 0.2 mg/kg of esketamine, or an equal volume of 0.9% normal saline placebo. Administration uses a customised nasal spray device with alternating nostrils every 5 minutes until the target dose is reached, given twice a week for 4 consecutive weeks (8 sessions in total). Safety monitoring during treatment includes ECG, blood pressure, blood oxygen levels and consciousness, and sleep will be recorded by actigraphy on treatment nights, with face-to-face follow-up at 1, 2 and 3 months after treatment to assess sleep, cognition, mood and activities of daily living.

Started
June 1, 2026
Type
interventional
Blinding
quadruple
Randomized
Yes
Registry ID
NCT07610343
RecruitingPhase NA

Effect of Low-dose Esketamine on Delirium in High-risk Elderly Patients Undergoing Elective Surgery (ELEMENT)

Double-blind, placebo-controlled randomised trial (n=1670) testing low-dose intraoperative and postoperative esketamine versus placebo to prevent postoperative delirium in high-risk elderly patients undergoing major non-cardiac surgery.

Started
February 1, 2025
Type
interventional
Blinding
double
Randomized
Yes
Registry ID
NCT06817239
CompletedPhase I/II

Efficacy of Sublingual 5-MeO-DMT for Reducing Anxiety and Depression in MCI (5-MeO-DMT)

This Phase I/II randomised, triple-blind, placebo-controlled trial (n=20) will study the effects of sublingual 5-MeO-DMT (6 mg, administered weekly for four weeks) on anxiety, depression, and cognitive function in individuals with mild to moderate Alzheimer's disease.

Started
December 15, 2024
Type
interventional
Blinding
triple
Randomized
Yes
Registry ID
NCT06812221
RecruitingPhase II

Ketamine for Veterans With Parkinson’s Disease (KPD)

This double-masked, active placebo-controlled, single-dose randomised trial (n=80) will investigate the effects of intravenous (IV) ketamine versus remimazolam for depression in Veterans with Parkinson’s disease (PD).

Started
July 1, 2024
Type
interventional
Blinding
triple
Randomized
Yes
Registry ID
NCT06231563
RecruitingPhase NA

Effect of Esketamine on Conscious State in Patients With pDoC

Randomised, quadruple-blind, parallel-group trial (n=116) assessing intraoperative IV esketamine 0.3 mg/kg versus saline on consciousness measures in patients with prolonged disorders of consciousness undergoing surgery under sevoflurane anaesthesia.

Started
May 1, 2024
Type
interventional
Blinding
quadruple
Randomized
Yes
Registry ID
NCT06389344
Active not recruitingPhase II

Does Psilocybin Change Synaptic Density in Amnestic Mild Cognitive Impairment

This Phase II interventional trial (n=60) aims to investigate whether psilocybin affects synaptic vesicular density (SVD) in individuals with amnestic Mild Cognitive Impairment (aMCI) compared to healthy participants.

Started
November 27, 2023
Type
interventional
Blinding
quadruple
Randomized
Yes
Registry ID
NCT06041152

Explore further

Search all Placebo papers Search all Neurocognitive Disorders trials Full Placebo profile Full Neurocognitive Disorders profile