Using Imaging to Assess Effects of THC on Brain Activity

Study Results

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Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

316 participants

Study Classification

INTERVENTIONAL

Study Start Date

2018-11-05

Study Completion Date

2021-01-21

Brief Summary

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This study will assess effects of tetrahydrocannabinol (THC) and THC + alcohol in marijuana users on prefrontal brain activity, using functional near-infrared spectroscopy (fNIRS) during resting state and during memory task performance. Participants will complete fNIRS testing 120 minutes following THC or identical placebo (Phase 2A), or THC/ethanol, THC/placebo ethanol, placebo THC/ethanol, and placebo THC/placebo ethanol (Phase 2B), and oxygenated hemoglobin (HbO) concentration will be measured.

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Detailed Description

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This study will assess the effects of THC intoxication using dronabinol (synthetic THC) on the oxyhemoglobin (HbO) signal during resting state and task-based activation in the prefrontal cortex (PFC) and resting state connectivity, as well as on neurocognitive task performance and correlations between these measurements and clinical signs of intoxication. Participants will be 150 adults who use marijuana at least monthly (aged 18-55) will be recruited to participate in this study. Participants will be given up to 80 mg of dronabinol, an FDA-approved synthetic form of THC that is used to treat loss of appetite that causes weight loss in people with AIDS. THC is the principle psychoactive drug in marijuana. The study will be conducted in regular cannabis users who present at their first study visit with a positive urine screen for THC metabolites.

Phase 2A. Investigate the effect of THC on fNIRS brain signature and its association with self-reported intoxication, laboratory measures of impairment, and the gold-standard behavioral field test of driving impairment used by law enforcement, the primary classifier.

Phase 2B. Examine potential interaction following co-administration of THC with oral ethanol exposure in healthy volunteers. Phase II is a randomized, double-blind, placebo-controlled, 2 by 2 crossover study of effect of dronabinol, ethanol, and combined dronabinol and ethanol on brain activation and connectivity as measured by fNIRS.

Conditions

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Intoxication Alcohol Intoxication THC Intoxication Combined Alcohol THC

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

In Phase 2A, a double-blind placebo-controlled, random order cross-over study of single dose dronabinol, participants received dronabinol or identical placebo on two separate study visits in randomized order.

In Phase 2B, a randomized, double-blind, 4-treatment, 4-period, crossover study with THC or placebo administration and ethanol or placebo administration, participants were randomly assigned to 1 of 24 sequences of each of the following treatments: placebo dronabinol and placebo ethanol, placebo dronabinol and ethanol, dronabinol and placebo ethanol, and dronabinol and ethanol.

Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

QUADRUPLE

Participants Caregivers Investigators Outcome Assessors

Subjects will be randomly assigned to one of the possible orders according to a randomization schedule generated by the study staff using a random number generator and computer program. The Massachusetts General Hospital (MGH) research pharmacy will generate a blinded randomization code for order of dosing and will dispense blinded drug in the dose ordered and identical placebo for use on separate study days. Ethanol or placebo drink will be prepared by a member of the research unit staff not otherwise associated with study visits.

Study Groups

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Phase 2A

In a double-blind placebo-controlled, random order cross-over study of single dose dronabinol, participants received dronabinol or identical placebo on two separate study visits in randomized order.

Group Type EXPERIMENTAL

Dronabinol

Intervention Type DRUG

Dronabinol at physician determined doses of 10-80mg designed to produce intoxication.

Placebo dronabinol

Intervention Type DRUG

Identical in appearance to active dronabinol (overencapsulation of both active and placebo dronabinol)

Phase 2B

In a randomized, double-blind, 4-treatment, 4-period, crossover study with THC or placebo administration and ethanol or placebo administration, participants were randomly assigned to 1 of 4 sequences and received each of the following treatments: placebo dronabinol + placebo ethanol, placebo dronabinol + ethanol, dronabinol + placebo ethanol, \& dronabinol + ethanol.

Group Type EXPERIMENTAL

Dronabinol

Intervention Type DRUG

Dronabinol at physician determined doses of 10-80mg designed to produce intoxication.

Ethanol

Intervention Type DRUG

Oral Ethanol, dosed to obtain a breath alcohol concentration (BrAC) of approximately 0.05 BrAC (equal to 1-2 standard drinks).

Placebo dronabinol

Intervention Type DRUG

Identical in appearance to active dronabinol (overencapsulation of both active and placebo dronabinol)

Placebo ethanol

Intervention Type DRUG

Placebo ethanol will consist of diet soda used in the active ethanol condition with 0.25ml ethanol floated on top to provide the odor of ethanol and blind the study drug.

Interventions

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Dronabinol

Dronabinol at physician determined doses of 10-80mg designed to produce intoxication.

Intervention Type DRUG

Ethanol

Oral Ethanol, dosed to obtain a breath alcohol concentration (BrAC) of approximately 0.05 BrAC (equal to 1-2 standard drinks).

Intervention Type DRUG

Placebo dronabinol

Identical in appearance to active dronabinol (overencapsulation of both active and placebo dronabinol)

Intervention Type DRUG

Placebo ethanol

Placebo ethanol will consist of diet soda used in the active ethanol condition with 0.25ml ethanol floated on top to provide the odor of ethanol and blind the study drug.

Intervention Type DRUG

Other Intervention Names

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oral THC oral ethanol placebo oral THC oral placebo ethanol

Eligibility Criteria

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Inclusion Criteria

1. Men and women aged 18-55 years, inclusive; (for Phase 2B: men and women aged 21-55 years, inclusive)
2. Competent and willing to provide written informed consent;
3. Able to communicate in English language.
4. Regular, at least monthly, marijuana use, confirmed by positive urine screen for THC

5. Past consumption of at least two alcoholic beverages in one occasion.
6. Past co-consumption of alcohol and THC at least once in lifetime with no serious adverse effects.
7. Weigh more than 100 lbs.

Exclusion Criteria

General (Phase 2A, 2B 3)

1. Any unstable, serious medical illness, or cardiovascular disease or events.
2. New or unstable psychiatric symptoms, schizophrenia, or bipolar I disorder,
3. Diabetes, cirrhosis, renal failure, Hepatitis C, HIV,
4. History of syncope without an identified situational stressor, migraines \>1x/month, head injury with prolonged unconsciousness (\> 24 hours);
5. Allergy to sesame oil (contained in Marinol pills) or Marinol capsules
6. Daily use of benzodiazepines or barbiturates, antihistamines, atropine, scopolamine, or other strong anticholinergic agents;
7. Current pregnancy or lactation, or trying to become pregnant (confirmed by urine pregnancy test)
8. In the opinion of the investigator, not able to safely participate in this study.

9. Currently seeking treatment, in treatment, or in recovery from an alcohol use disorder.

Minimum Eligible Age

18 Years

Maximum Eligible Age

55 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes