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Psilocybin and Brain Activity Study

This study is looking at how psilocybin, a compound found in certain mushrooms, affects thoughts and brain activity in healthy volunteers. You would receive either psilocybin (10 mg) or a placebo (an inactive substance) in a capsule. Researchers will use computer tasks, EEG (a test that measures brain waves), and MRI (a type of scan that takes detailed pictures of organs and tissues) to see how psilocybin changes creativity, thought processes, and memory. The goal is to better understand how psychedelic drugs work and how they might be used in the future. The study aims to enroll 30 healthy adults between 18 and 75 years old who are fluent in English and have at least a high-school education. Success will be measured by changes in word use during tasks, how well you recognize visual stimuli, and accuracy on a remote associates task, all assessed at 8 weeks.

Study design
This is a double-blind, placebo-controlled study, meaning neither you nor the researchers will know if you're receiving psilocybin or placebo. It's a within-subject, full cross-over study with 30 planned participants.
What's involved
You would undergo screening, including a personal interview, medical questionnaire, physical exam, electrocardiogram (ECG), and routine tests. You would also participate in computerized tasks, EEG, and MRI measurements.
Compensation
Not stated in the trial record.
Follow-up
The primary endpoints are measured at 8 weeks, indicating a follow-up period of at least that long.

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NCT05301608

Effects of Psilocybin on Electrophysiology and the Dynamic Content of Thought

Recruiting
PHASE1Ages 18–75InterventionalBasic science
Johns Hopkins University
~30 participants
Updated 2026-07-23 on ClinicalTrials.gov
What's tested:PsilocybinPlacebo

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Difference between drug conditions in the frequency of word use during free association tasks
Measured over 8 weeks
+5 more outcomes measured

Conditions

Healthy

Explore related trials

Healthy

Where it's being run

1 sites across 1 states
Maryland1

Study leadership

  • Frederick S Barrett, PhD · PRINCIPAL_INVESTIGATOR · Johns Hopkins University

Who to contact

Gabi Lofland
[email protected]
(410) 550-2253
Email the study team

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Do you actually qualify for this trial?

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Eligibility criteria

Inclusion

18 to 75 years old
Have given written informed consent
Have at least a high-school level of education or equivalent (e.g. GED) and be fluent in English
Be healthy and psychologically stable as determined by screening for medical and psychiatric problems via a personal interview, a medical questionnaire, a physical examination, an electrocardiogram (ECG), and routine medical blood and urinalysis laboratory tests
Agree to consume approximately the same amount of caffeine-containing beverage (e.g. coffee, tea) that he/she consumes on a usual morning, before arriving at the research unit on the morning of the drug session day. If the participant does not routinely consume caffeinated beverages, he/she must agree not to do so on the session day.
Agree to refrain from using any psychoactive drugs, including alcoholic beverages and nicotine, within 24 hours of each drug administration. The exception is caffeine.
Agree not to take any "as-needed" medications on the mornings of drug sessions
Agree not to take sildenafil (Viagra®), tadalafil, or similar medications within 72 hours of each drug administration.
Agree that for one week before each drug session, he/she will refrain from taking any nonprescription medication, nutritional supplement, or herbal supplement except when approved by the study investigators. Exceptions will be evaluated by the study investigators and will include acetaminophen, non-steroidal anti-inflammatory drugs, and common doses of vitamins and minerals.
Have used a psychedelic drug (e.g. lysergic acid diethylamide(LSD)/acid, psilocybin mushrooms, ayahuasca) at least five times in their lifetime.
Proof of COVID-19 vaccination

Exclusion

Women who are pregnant (as indicated by a positive urine pregnancy test assessed at intake and before each drug session) or nursing; women who are of child-bearing potential and sexually active who are not practicing an effective means of birth control.
Cardiovascular conditions: coronary artery disease, stroke, angina, uncontrolled hypertension, a clinically significant ECG abnormality (e.g. atrial fibrilation), artificial heart valve, or heart attack in the past year
Epilepsy with history of seizures
Insulin-dependent diabetes; if taking oral hypoglycemic agent, then no history of hypoglycemia
Currently taking psychoactive prescription medication on a regular (e.g. daily) basis
Currently taking on a regular (e.g. daily) basis any medications having a primary centrally-acting serotonergic effect, including mono-amine oxidase inhibitors (MAOIs). For individuals who have intermittent or "as needed" use of such medications, psilocybin sessions will not be conducted until at least five half-lives of the agent have elapsed after the last dose.
More than 20% outside the upper or lower range of ideal body weight according to Metropolitan Life height and weight table
Current or past history of meeting Diagnostic and Statistical Manual, version 5 (DSM-5) criteria for schizophrenia spectrum or other psychotic disorders (except substance/medication-induced or due to another medical condition)
Current or past history within the last five years of meeting DSM-5 criteria for a moderate or severe alcohol or drug use disorder (excluding caffeine and nicotine)
Have a first or second-degree relative with bipolar I disorder, schizophrenia spectrum, or other psychotic disorders (except substance/medication-induced or due to another medical condition)
Has a psychiatric condition judged to be incompatible with establishment of rapport or safe exposure to psilocybin
Has history of migraine, tension, or other recurring headaches.
Head trauma, traumatic brain injury, or concussion with loss of consciousness for \>2 minutes
Contraindications for magnetic resonance imaging (MRI) (e.g. claustrophobia incompatible with MRI scanning, medical device or implant incompatible with MRI, prior history as a metal worker and/or certain metallic objects in the body)
Left-handedness (assessed by the Edinburgh Handedness Inventory)

What this trial measures

  • Difference between drug conditions in the frequency of word use during free association tasks8 weeks

    Volunteers are instructed to either describe their interpretation of visual stimuli, verbalize a set of freely associated words, or reflect upon and describe out loud the thoughts that are occurring after presentation of short excerpts of popular music. Audio recordings of verbal responses from volunteers will be recorded, transcribed, and then submitted to automated text analysis and natural language processing analysis to compare the semantic content of responses between those that were provided during placebo and those that were provided during psilocybin conditions. The frequency of words that fall into a series of semantic categories (e.g. pronouns, adjectives, positive vs negative valence words) will be compared between drug conditions.

  • Sensitivity in distinguishing old versus newly presented visual stimuli8 weeks

    During drug administration sessions, volunteers will view a series of visual stimuli (words and images) and will be asked to read and remember each visual stimulus. The next day, volunteers will be presented with stimuli that were as well as stimuli that were not presented the previous day, and they will be asked to indicate the confidence with which they remember seeing the given stimulus before ("old") or not ("new"). Sensitivity in distinguishing between old and new words (d') will be calculated from receiver operator characteristic curve analysis of confidence ratings of "new" vs "old" judgements, and compared between drug conditions.

  • Accuracy in the remote associates task as assessed by total correct number of trials8-week study period

    Participants will be presented with three words that are only remotely related to each other (e.g., falling, actor, dust) and ask them to generate a fourth word (e.g., star) that relates to all three words. Total correct number of trials will be compared between drug conditions.

  • Accuracy in the alternative uses task8-week study period

    The Alternative Uses Task assesses the extent one can generate novel uses for presented stimuli (e.g. a brick, or a paper clip). The total number of responses and the number of uniquely novel uses that were generated will be compared between drug conditions.

  • Alpha band power in EEG record8-week study period

    Continuous EEG recordings will be analyzed using spectral decomposition, and the time course of average power in the alpha frequency band will be compared between drug conditions.

  • Reliability of whole-brain response while watching videos8-week study period

    Volunteers will be presented with videos during scanning in the second two drug administration sessions. These will be otherwise unremarkable 6-15 minute videos of natural scenes, human interactions, or narrative stories. We will calculate correlations in measured brain response across subjects, moment-by-moment, which yields a measure of reliability of response to these videos across the brain. This reliability map will be compared between drug conditions.