Acute Effects of Cannabis on Cognition and Affect
ConditionCannabis Use
Trial statusRecruiting
Trial phasePhase 2
Trial typeInterventional
Biological sexAll
Age21+
SponsorWashington State University
About this trial
This study will examine how a moderate dose of THC affects mood and cognitive functioning in regular cannabis users. The study uses a double-blind, placebo-controlled, crossover design, meaning each participant will complete two sessions. Specifically, each participant will be given active cannabis (20 mg THC) in one session, and placebo in the other session. The order will be randomized across participants, so half will receive cannabis first, and the other half will receive placebo first.
Ninety two adults who use cannabis at least weekly will be recruited from the local community. After an online screening survey, eligible participants will attend a laboratory visit where the participants will provide informed consent and complete saliva and urine drug tests to confirm recent abstinence from cannabis and absence of other drugs. Participants who pass screening will complete baseline questionnaires of cannabis use patterns, depression, anxiety, ADHD symptoms, emotion regulation, affect, and demographic information.
Cannabis and placebo materials (obtained from NIDA) will be vaporized using a Volcano vaporizer device. Participants will inhale the vapor under supervision, and neither the participant nor the researcher assessing outcomes will know which product is administered. After vaping, participants will complete repeated mood ratings and a battery of cognitive tests assessing executive functions like planning, inhibition, working memory, and cognitive flexibility. The participants will then watch a nature video and report their feelings of awe and affect.
At the end of each session, participants will remain in a supervised room with entertainment and snacks until at least four hours have passed since vaping and the participants report feeling sober. The participants will then return for a second session with the opposite study condition (THC or placebo) one week later. Both sessions follow the same procedures. Participants are fully debriefed after completing the study.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
be 21 years of age or older
be fluent in English
use of cannabis at least once a week for at least one year
inhalation as their typical method of administration
Disqualifiers
neurological conditions (e.g., neurodegenerative disorders, severe head injury, multiple concussions)
serious psychiatric conditions (e.g., psychosis, bipolar disorder)
family history of psychosis
intellectual disabilities or learning disorders (e.g., dyslexia)
Trial design
Design model
Crossover
Treatments tested in this trial
THC 20mg
Drug20 mg THC delivered by vaporizing 0.17 g of 11.86% THC cannabis flower obtained from NIDA, using a Volcano vaporizer.
Placebo
DrugPlacebo obtained from NIDA and vaporized using a Volcano vaporizer.
Treatment groups
92 Participants
are divided into 2 treatment groupsGroup A: THC -> PlaceboExperimental treatment 2 interventions
Group B: Placebo -> THCExperimental treatment 2 interventions
Trial outcomes
Primary outcomes
1
Event-Based Prospective Memory - Number of Difficulty Ratings Provided
Event-based prospective memory will be assessed using a difficulty ratings task. At the beginning of the session, participants will be asked to try to remember to rate how difficult they found each test immediately after it is completed, using a 0 (not at all difficult) to 10 (extremely difficult) scale. The primary outcome of interest is the number of difficulty ratings they remember to provide.
Time frame
This outcome will be assessed during both sessions, within 90 minutes post-treatment.2
Time-Based Prospective Memory - Token Task
Time-based prospective memory will be assessed using a token task. Participants will be instructed to try to remember to request a token every 10 minutes. A clock will be positioned face down on the table for them to refer to the time, and we will record their clock-checking behavior. The primary outcome is the number of times they remember to request the token, out of the total time of the cognitive assessment session.
Time frame
This outcome will be assessed during both sessions, within 90 minutes post-treatment.3
Working Memory Updating - N-back Test Accuracy
Cognitive flexibility and working memory updating will be assessed using the N-back test. Participants are shown strings of letters one at a time and are instructed to indicate whenever a letter appears that matches the letter shown two trials earlier. Outcomes include the percentage of correct responses made (i.e., the number of times they correctly recognize that the current letter matches the one from two trials before, etc.).
Time frame
This outcome will be assessed during both sessions, within 90 minutes post-treatment.4
Working Memory Updating - N-back Reaction Time
Cognitive flexibility and working memory updating will be assessed using the N-back test. Participants are shown strings of letters one at a time and are instructed to indicate whenever a letter appears that matches the letter shown two trials earlier. Outcomes include the mean reaction time (milliseconds) for correct responses on the task.
Time frame
This outcome will be assessed during both sessions, within 90 minutes post-treatment.Secondary outcomes
1
Event-Based Prospective Memory - Difficulty Ratings
Event-based prospective memory will be assessed using a difficulty ratings task. At the beginning of the session, participants will be asked to try to remember to rate how difficult they found each test immediately after it is completed, using a 0 (not at all difficult) to 10 (extremely difficult) scale. The primary outcome of interest is the self-reported difficulty of each task completed.
Time frame
This outcome will be assessed during both sessions, within 90 minutes post-treatment.2
Time-Based Prospective Memory - Token Task Clock-Checking
Time-based prospective memory will be assessed using a token task. Participants will be instructed to try to remember to request a token every 10 minutes. A clock will be positioned face down on the table for them to refer to the time, and we will record their clock-checking behavior. The primary outcome is the number of times they check the clock over the duration of the cognitive assessment session.
Time frame
This outcome will be assessed during both sessions, within 90 minutes post-treatment.3
Planning - Tower Test Time to Completion
Planning and problem-solving abilities will be assessed using the Tower Test. Participants are asked to move disks to reach a specified end configuration in as few moves as possible. They can move only one disk at a time and cannot place a larger disk on top of a smaller disk. Outcomes on this task include the time taken to complete each tower problem.
Time frame
This outcome will be assessed during both sessions, within 90 minutes post-treatment.4
Cogntiive Flexibility - Verbal Fluency, Category Switching Errors
Cognitive flexibility (category switching) will be assessed using the verbal fluency category switching task. Participants will be given two categories (e.g., fruits and furniture) and be asked to generate words that belong to those categories, in alternating order, within a time limit of 60s. Outcomes on this task include repetition and intrusion (i.e., non-category words) errors.
Time frame
This outcome will be assessed during both sessions, within 90 minutes post-treatment.Other outcomes
1
Cannabis Consumption Patterns
As part of their baseline assessments, participants will complete the Daily Sessions, Frequency, Age of Onset, and Quantity of Cannabis Use Inventory, which is a standardized, valid, and reliable measure of their cannabis consumption patterns. The information from this survey will be used to characterize the sample and determine cannabis use-related covariates that should be controlled for in analyses.
Time frame
This outcome will be assessed at baseline (i.e., during the testing session but before treatment).2
Drug Screen
Participants will complete a 12-panel urine drug test to ensure they test positive for cannabis/THC but no other illicit drugs.
Time frame
This outcome will be assessed during both sessions at baseline (i.e., during the testing session but before treatment).3
Temperature
An Empatica E4 medical-grade device will be used to collect continuous measures of temperature.
Time frame
This outcome will be continuously assessed during both sessions from before drug/placebo administration to immediately before they leave the lab (approximately 5 hours).4
Post-Session Intoxication Ratings
Participants will be asked to rate how high they feel using a scale from 0 (not high at all) to 10 (extremely high) while relaxing and sobering up, following the rest of their session.
Time frame
This outcome will be assessed every 30 minutes from 2 hours post-dose through 4 hours post-dose (or until the participant reports sobriety, whichever occurs later).Sponsors and contacts
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Source ClinicalTrials.gov