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NCT Number: NCT06647524

Pilot fMRI Studies of Aging-Related Effects of THC

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.

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Key information

Conditions

THC Memory Disorders Nervous System Diseases Neurobehavioral Manifestations Neurologic Manifestations Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Olin Neuropsychiatric Research Center at Hartford Healthcare

Hartford, Connecticut, 06106, United States

Location status: Recruiting

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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 the study protocol.

Exclusion criteria

  • Current marijuana tolerance, desire to cut down, or cravings to use during periods of abstinence.
  • 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
  • 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
  • Hearing loss such that subject cannot hear sounds at the levels (dB) or pitches (Hz) to be used in the study
  • Significant pain and/or reduced mobility in the arms

Treatment and study plan

THC

Drug

Participants will be administered 0.5g of vaporized THC cannabis (12% THC cannabis)

Placebo

Drug

Participants will be administered identical plant material from which all THC has been removed by solvent extraction.

Primary outcomes

  1. The Complex Working Memory Span (CWMS) Task- Items Recalled

    Time frame: At sessions 1 and 2 while under fMRI, immediately post drug administration

    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.

  2. The Complex Working Memory Span (CWMS) Task- fMRI measure

    Time frame: At sessions 1 and 2 while under fMRI, immediately post drug administration

    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.

  3. The Effort Expenditure for Reward Task (EEfRT)

    Time frame: At sessions 1 and 2 immediately post drug administration

    (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.

  4. The Card-Guessing fMRI task

    Time frame: At sessions 1 and 2 while under fMRI, immediately post drug administration

    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.

  5. The Zibrio SmartScale

    Time frame: At sessions 1 and 2 while under fMRI, immediately post drug administration

    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.

Study contacts

Contact information is provided by the study sponsor or research team.

Ariana Caruso

CONTACT

[email protected]

Godfrey Pearlson, MD

CONTACT

[email protected]

860-305-8921

Sponsors and collaborators

Lead sponsor

Yale University

Other

Collaborators

  • Biopharmaceutical Research Company
  • Bloom Labs Cannabis Solutions

Registry information

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Oct 17, 2024
Registry last updated
Oct 9, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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