A Phase 2 interventional study of THC and Placebo in THC, sponsored by Yale University. Recruiting at 1 site in United States. Open to participants aged 18 Years to 75 Years. Per ClinicalTrials.gov, last updated 2025-10-09.
Sponsored by Yale University · Phase 2, Interventional, and Basic science
The purpose of this study is to begin investigating acute impairment of various forms of memory and learning by Tetrahydrocannabinol (THC) in cannabis (CNB) compared to placebo, in a 2-session per subject double-blind, random assignment, placebo-controlled counterbalanced design in young to middle-aged adults.
Tasks tapping each of the major cognitive memory-related domains will be performed in the MRI scanner, to reveal the relevant underlying circuitry and its disruption by drug using functional MRI.
On an initial Screening Visit, regular or novice cannabis (CNB) users will undergo informed consent, clinical assessment (to fully evaluate inclusion/exclusion criteria), cognitive/personality assessment, and a structural MRI scan.
At each assessment, subjects will provide subjectively-rated CNB intoxication using a verbal analog scale, complete 2 fMRI paradigms within \~1.5 hours: a) Card Guessing task and b) Complex Working Memory Span, and complete the computer-based Effort Expenditure for Reward Task within \~2 hours. These tests will be counterbalanced across subjects and sessions to minimize order and fatigue effects. Breaks will be standardized in a private environment and snacks/meals provided. Bathroom visits given as needed. Subjects will be supervised at all times by study staff and vital signs monitored. On assessment days, participants will remain at the Olin NRC until they report no subjective intoxication, and are observed by study staff to be no longer objectively intoxicated, then use taxi or Uber transportation home.
373 studies on the registry are indexed under Memory Disorders; 67 are open to participants now.
This study's planned enrollment of 10 is below the median of 72 across 298 interventional studies indexed under Memory Disorders.
Browse Memory Disorders studies →Yale University is the lead sponsor of 1,770 studies on the registry; 294 are open to participants now.
Of its 221 completed or terminated interventional studies of FDA-regulated products, 129 (58%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants in this arm will receive THC then placebo in a 2-session per subject double-blind, random assignment, placebo-controlled counterbalanced design. (Participants randomized to receive THC in the first session will receive placebo at the 2nd session.) Sessions will be scheduled at least one week apart. Tasks tapping each of the major cognitive memory-related domains will be performed in the MRI scanner, to reveal the relevant underlying circuitry and its disruption by drug using functional MRI.
Drug: THC · Drug: Placebo
Participants in this arm will receive placebo then THC in a 2-session per subject double-blind, random assignment, placebo-controlled counterbalanced design. (Participants randomized to receive placebo in the first session will receive THC at the 2nd session.) Sessions will be scheduled at least one week apart. Tasks tapping each of the major cognitive memory-related domains will be performed in the MRI scanner, to reveal the relevant underlying circuitry and its disruption by drug using functional MRI.
Drug: THC · Drug: Placebo
Participants will be administered 0.5g of vaporized THC cannabis (12% THC cannabis)
Participants will be administered identical plant material from which all THC has been removed by solvent extraction.
The Complex Working Memory Span (CWMS) Task- Items Recalled
CWMS Task assesses immediate plus delayed recall and working memory by assessing working memory capacity by presenting a list of stimuli to be recalled while simultaneously performing a secondary task. This task uses a fully crossed design which includes both same-domain CWMS conditions (e.g. verbal storage combined with verbal processing) as well as cross-domain CWMS conditions (e.g., verbal storage combined with spatial processing). Mean number of total items recalled.
Time frame: At sessions 1 and 2 while under fMRI, immediately post drug administration
The Complex Working Memory Span (CWMS) Task- fMRI measure
CWMS Task assesses immediate plus delayed recall and working memory by assessing working memory capacity by presenting a list of stimuli to be recalled while simultaneously performing a secondary task. This task uses a fully crossed design which includes both same-domain CWMS conditions (e.g. verbal storage combined with verbal processing) as well as cross-domain CWMS conditions (e.g., verbal storage combined with spatial processing). BOLD signal Infrontal lobe.
Time frame: At sessions 1 and 2 while under fMRI, immediately post drug administration
The Effort Expenditure for Reward Task (EEfRT)
(EEfRT) is an out-of-scanner measure of effort-based decision-making that utilizes a choice model ("easy-task" or "hard-task") in response to varying monetary rewards. This task assesses motivation in relation to reward magnitude, implicating the activation or suppression of dopaminergic pathways in the nucleus accumbens (NAcc). Percentage of hard-task choices across all levels of probability is calculated from all hard choices. Lower percentages of hard task choices indicate decreased motivation.
Time frame: At sessions 1 and 2 immediately post drug administration
The Card-Guessing fMRI task
The Card-Guessing fMRI task (28) will be used to investigate the effects of acute THC intoxication on decision-making, risk-taking, and reward processing. This task involves various trial types including win, loss, disappointment, and relief, to assess how THC affects reward expectancy and prediction error processing during decision-making presented as the fMRI blood-oxygen-level-dependent (BOLD) signal in response to card-guessing task.
Time frame: At sessions 1 and 2 while under fMRI, immediately post drug administration
The Zibrio SmartScale
The Zibrio SmartScale aggregates balance data to create a "Balance Score", which assesses postural sway with respect to balance ability and fall risk. Total score range 1 and 10. A lower score indicates a higher risk of falling.
Time frame: At sessions 1 and 2 while under fMRI, immediately post drug administration
Plan to share: No
No publications or documents are linked to this record.
Started Jul 2025 (actual). Primary completion is estimated for Dec 2027, 29 months after the start.
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Studies of the drug tested here: Dronabinol