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THC Memory & Reward Learning Pilot

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ClinicalTrials.gov Identifier: NCT05116527
Recruitment Status : Recruiting
First Posted : November 11, 2021
Last Update Posted : August 5, 2022
Yale University
Information provided by (Responsible Party):
Godfrey Pearlson, Yale University

Brief Summary:
Tetrahydrocannabidiol (THC) is the psychoactive chemical in cannabis that makes people high. This study aims to dissect acute impairment of various forms of memory and learning by THC in cannabis compared to placebo. Impairment will be assessed via a short cognitive test battery and then subjects will complete four tasks in the fMRI scanner.

Condition or disease Intervention/treatment Phase
Marijuana THC Cannabis Drug: Marijuana, Hash, THC, or Grass Drug: Placebo Phase 1 Phase 2

Detailed Description:

The protocol below is designed to begin dissecting acute impairment of various forms of memory and learning by THC in cannabis compared to placebo, in a 2-session per subject double-blind, random assignment, placebo-controlled counterbalanced design in young to middle-aged adults. The purpose of these experiments is to gather important pilot data to demonstrate proof of principle for a planned NIDA submission of a P50 center application that will examine cannabis's differential effects on the neural circuit underpinnings these various cognitive domains across the lifespan in much more detail. In other words, these pilot data will show NIDA that the investigators' methods and approaches work and are suitable for use in their proposed center grant application. Unlike in the planned P50, in these small-scale pilot studies the investigators are only concerned with comparing these disrupting effects using a single dose of THC versus placebo, without exploration of age, sleep, or sex-related differential effects or of different dose-related effects.

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. Although each of the fMRI tasks is already implemented in the investigators' lab in other contexts, the investigators have never studied alteration of the fMRI tasks by THC. Neither have other investigators elsewhere used this approach. It is also important to point out that the dose of active THC to be administered is the same as that already used safely in the investigators' IRB-approved driving studies, one which subjects state subjectively (a blind to actual dose information) makes them feel moderately intoxicated, and similar to the amount that they would consume themselves recreationally.

The study will consist of 3 days (screening visit and 2 dose days). In a randomized, counterbalanced, double-blind study, investigators will administer high THC marijuana or placebo marijuana using paced inhalation through a vaporizer. Following administration, subjects will provide subjectively-rated CNB intoxication using a verbal analog scale, a short cognitive test battery, then complete 4 fMRI paradigms within ~1.5 hours: a) MSDM task, b) MID task, c) RISE task, and d) Treadway Effort/Reward task. These tests will be counterbalanced across subjects and sessions to minimize order and fatigue effects.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 20 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Intervention Model Description: All subjects will receive both study drug and placebo.
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Other
Official Title: Pilot fMRI Studies of THC Effects on Memory and Reward Learning
Actual Study Start Date : July 7, 2022
Estimated Primary Completion Date : February 2024
Estimated Study Completion Date : February 2025

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Marijuana Memory

Arm Intervention/treatment
Experimental: High Dose THC
Participants will receive high dose THC.
Drug: Marijuana, Hash, THC, or Grass
Marijuana flower with a high THC content
Other Names:
  • Marijuana
  • THC

Experimental: Placebo THC
Participants will receive placebo THC.
Drug: Placebo
Placebo THC - marijuana flower with no THC content

Primary Outcome Measures :
  1. Marijuana induced performance changes on fMRI Multi-Stage Decision Making (MSDM) Task. [ Time Frame: Baseline and post drug administration at 10 minutes. ]
    The MSDM is a reinforcement learning paradigm that quantifies the degree to which subjects can integrate recent trial-to-trial information about a stimulus' likelihood of reward with acquired knowledge about whether some choices generally lead to disadvantageous outcomes vs. others that more often lead to reward.

  2. Marijuana induced performance changes on Relational and Item Specific Coding (RISE) fMRI Task. [ Time Frame: Baseline and post drug administration at 10 minutes. ]
    The RISE task is a hippocampal-dependent learning paradigm that assesses declarative memory.

  3. Marijuana induced performance changes on fMRI Treadway/Effort Reward Task. [ Time Frame: Baseline and post drug administration at 10 minutes. ]
    The Treadway Effort/Reward Task independently measures the neural responses to two dimensions of a cost/benefit decision: the effort required and the magnitude of reward.

  4. Marijuana induced performance changes on fMRI Monetary Incentive Delay (MID) Task. [ Time Frame: Baseline and post drug administration at 10 minutes. ]
    The MID task probes the brain's reward system to assess the anticipation and receipt of rewards or punishment.

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 55 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • 18-55 years old
  • Right handed
  • CNB use within past 2 years and felt "high" when used
  • Able to read, speak, and understand English
  • Able and willing to provide written informed consent, and willing to commit to study protocol.

Exclusion Criteria:

  • Current marijuana tolerance, desire to cut down, or cravings to sue during periods of abstinence.
  • Strongly left-handed
  • Positive screen for drug or alcohol (except CNB) on test day will result in rescheduling the appointment
  • History of adverse effects with CNB
  • CNB users who are abstaining
  • Report of any psychotic disorder in a first degree relative
  • IQ < 80 on the Wechsler Abbreviated Scale of Intelligence
  • Inability to comprehend written instructions using the WRAT-4 reading achievement test
  • Pregnant, breastfeeding, and ineffective birth control methods.
  • Unable or unsafe to have an MRI
  • Serious medical, neuro-ophthalmological, or neurological illness (e.g. cancer, seizure disorders, encephalopathy
  • History of head trauma with loss of consciousness > 30 minutes or concussion lasting 30 days.
  • Focal brain lesion seen on structural MRI
  • Any medical/neurological condition that could compromise neurocognitive performance (e.g. epilepsy, multiple sclerosis, fetal alcohol syndrome).
  • Anyone deemed unsafe to study personnel for any reason

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT05116527

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Contact: Suyash Adhikari, B.S 860-545-7106 Suyash.Adhikari@hhchealth.org
Contact: Diana King, B.A 860-545-7563 Diana.King@hhchealth.org

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United States, Connecticut
Hartford Hospital Recruiting
Hartford, Connecticut, United States, 06102
Contact: Diana King, B.A    860-545-7563    Diana.King@hhchealth.org   
Contact: Suyash Adhikari, B.S    860-545-7106    Suyash.Adhikari@hhchealth.org   
Sponsors and Collaborators
Hartford Hospital
Yale University
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Principal Investigator: Godfrey Pearlson, M.D Yale University
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Responsible Party: Godfrey Pearlson, Founding Director Olin Neuropsychiatry Research Center; Professor Yale University, Yale University
ClinicalTrials.gov Identifier: NCT05116527    
Other Study ID Numbers: HHC-2021-0195
First Posted: November 11, 2021    Key Record Dates
Last Update Posted: August 5, 2022
Last Verified: August 2022

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Studies a U.S. FDA-regulated Drug Product: Yes
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Godfrey Pearlson, Yale University:
Additional relevant MeSH terms:
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Marijuana Abuse
Substance-Related Disorders
Chemically-Induced Disorders
Mental Disorders