CannabisCOBRA 3NCT06669585
Cannabis Observations on Brain Waves, Retrieval, and Attention: Experiment 3
An observational study of Cannabis and Memory, run by L. Cinnamon Bidwell at 1 site in United States.
Trial summary
This study investigates the impact of ∆9-tetrahydrocannabinol (THC) and cannabidiol (CBD) on recognition memory in healthy, regular cannabis users. Participants complete the same recognition memory task after self-administering one of two different strains of cannabis flower one day and while not intoxicated another… Read more about this study
- Who is it for?
- Ages 21 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Cannabis, Memory, Electroencephalography
- What is being tested?
- Cannabis (smoked flower)
- How many people
- 96 participants
- Where
- 1 siteUnited States
- Study dates
- 9 Oct 2024to 10 Dec 2025
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 21 to 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Study population: Community sample of healthy, regular cannabis users in the Boulder and Denver areas
Who may be able to join
- Must be between the ages of 21 and 40 and provide informed consent;
- Must be right-handed (Laterality Quotient > 60 on Edinburgh Handedness Inventory - Short Form);
- Must use cannabis at least 4 days during the month;
- Must be a cannabis user for at least a year;
- Must self-report not using other illicit recreational drugs (e.g., cocaine, benzodiazepines (non-prescription), opiates (non-prescription), MDMA, sedatives, or methamphetamine) in the past 30 days, during the Pre-Screening;
- Must not test positive on a urine toxicology test for drugs of abuse at the Baseline appointment;
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- Must not be using psychotropic medications, however anti-depressant, non-benzodiazepine anti-anxiety, and ADHD medications are ok. ADHD medication users must be willing to abstain from ADHD medication use on appointment days;
- Must not be a regular nicotine user (≤4 days per week; cigarette, E-cigs, or smokeless);
- Must not have used caffeine or nicotine (cigarette, E-cigs, or smokeless) for 4 hours before each appointment;
- Must have a breath alcohol level of 0 at Baseline appointment (to sign consent form);
- Must not be actively seeking or in treatment for any substance use disorder;
- Female subjects must not be or trying to become pregnant (as indicated by a pregnancy test administered at Baseline appointment);
- Must not be in treatment for psychotic disorder or bipolar disorder; or have a history with these disorders;
- Must not have any physical characteristics (e.g., thick hair, head size exceeding the limit of the net, dyed hair) or experience any technical difficulties during testing that result in a poor-quality EEG recording.
Who cannot join
None listed.
Trial locations and contacts
1 site in 1 country.
United States1 site
Center for Innovation and Creativity (CINC)
Boulder, Colorado, 80301
About this study
Official title: Cannabis Observations on Brain Waves, Retrieval, and Attention: Experiment 3 (COBRA)
This study investigates the impact of ∆9-tetrahydrocannabinol (THC) and cannabidiol (CBD) on recognition memory in healthy, regular cannabis users. Participants complete the same recognition memory task after self-administering one of two different strains of cannabis flower one day and while not intoxicated another day. Event-related potentials (ERPs) are measured via electroencephalogram (EEG) during the recognition memory task. Blood is collected to quantify THC and CBD exposure. Participants also complete self-report measures of medical history, sleep quality, subjective cognitive function, physical activity, psychological functioning, substance use, and acute drug effects.
Read the detailed description
Previous research has established cannabis's harmful cognitive impact, with particularly robust and consistent effects in the domain of episodic memory. However, prior work has not sufficiently considered that the memory effects of cannabis are the compound action of different cannabinoids, which vary in their pharmacology and effects. Specifically, CBD, a non-psychotomimetic component of cannabis (doesn't produce a "high"), is thought to have cognitively protective properties and may mitigate some of the harmful effects of THC. Further, few prior studies have tested the effects of high potency strains that are commonly available.
This study tests the effects of commercially available cannabis flower strains on recognition memory performance and ERPs that are related to different underlying memory processes in healthy, regular cannabis users. An episodic memory task is used to assess recognition memory, which asks participants to discriminate between previously studied and non-studied items using pictures as stimuli. Participants complete the same memory task while intoxicated one day and not intoxicated another day. A THC-dominant strain and a strain containing both THC and CBD are included in the study. Participants self-administer one of the two cannabis strains prior to memory encoding and retrieval.
Blood is collected to determine THC and CBD exposure, as well as to explore how genetic variation in genes related to cannabinoid metabolism, cannabis-related behavior, and neurocognitive function associate with memory function before and after cannabis use. Participants also complete self-report measures of medical history, sleep quality, subjective cognitive function, physical activity, psychological functioning, substance use, and acute drug effects.
- Conditions
- Cannabis, Memory, Electroencephalography
- Being tested
- Cannabis (smoked flower)
- Keywords
- Cannabis, Memory, Electroencephalography
- Medical subject headings
- Marijuana Abuse
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Cannabis (smoked flower)Drug
Self-Directed Use (ad-libitum)
What is being measured
The primary outcome is the main question the study is designed to answer.
Difference in ERP amplitude (FN400)
Electroencephalography is used to quantify FN400.
Measured: Intoxicated session and not-intoxicated session (about 1 week)
Difference in ERP amplitude (parietal)
Electroencephalography is used to quantify parietal ERP effects.
Measured: Intoxicated session and not-intoxicated session (about 1 week).
Difference in retrieval memory accuracy
Accuracy will be used to assess task performance.
Measured: Intoxicated session and not-intoxicated session (about 1 week)
Difference in retrieval memory performance
Reaction time will be used to assess task performance.
Measured: Intoxicated session and not-intoxicated session (about 1 week)
Secondary outcomes (8)
Change in Positive and Negative Affect Schedule (PANAS)
The PANAS is Self-report measurement of positive and negative affect. Both subscales range from 1 - 50, with a higher score on the positive affect scale indicating higher positive affect and a higher score on the negative affect scale indicating higher negative affect.
Measured: Before and after acute cannabis use during intoxicated session
Change in Drug Effects Questionnaire (DEQ)
The DEQ is a visual analogue scale of measure of acute drug effects. Participants are asked 5 questions on the DEQ, each of which range from 0 - 100, with higher values for each item indicating greater drug effect.
Measured: Before and after acute cannabis use during intoxicated session
Change in Addiction Research Center Inventory (ARCI-M)
The ARCI-M is a self-report measure of subjective effects of marijuana. This is a 12-item true-false task, in which higher (true) scores indicate greater intoxication.
Measured: Before and after acute cannabis use during intoxicated session
Change in Marijuana Craving Questionnaire
The Marijuana Craving Questionnaire is a self-report measure of marijuana craving. Participants complete 8 questions ranging from 0 - 10, with a higher score indicating greater cannabis craving and somatic symptoms.
Measured: Before and after acute cannabis use during intoxicated session
Change in Profile of Mood States (POMS)
The POMS is a self-report measure of mood. Participants complete 27 mood-related items ranging from 0 - 4, with higher scores indicating greater levels of specific mood states.
Measured: Before and after acute cannabis use during intoxicated session
Change in Alcohol Craving Questionnaire
The Alcohol Craving Questionnaire is a self-report measure of alcohol craving. This is a 2-item scale with each item ranging 0 - 10, with higher scores indicating greater alcohol craving.
Measured: Before and after acute cannabis use during intoxicated session
Change in State Adapted Paranoia Checklist-Brief (SAPC-B)
The SAPC-B is a self-report measure of paranoia. Participants complete 5 items each ranging from 0 - 10, with higher scores indicating greater feelings of paranoia.
Measured: Before and after acute cannabis use during intoxicated session
Difference in circulating cannabinoid concentration
Blood levels of THC and CBD will be quantified.
Measured: Baseline, intoxicated session, and not-intoxicated session (about 3 weeks total over all three sessions)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Nov 2024
- Study start9 Oct 2024
- Primary completion10 Dec 2025
- Study completion10 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for CannabisStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 96 participants (actual)
Sponsor and investigators
- Lead sponsor
- L. Cinnamon Bidwell
- Sponsor type
- University, hospital or other
- Collaborators
- National Institute on Drug Abuse (NIDA)
- Responsible party
- Sponsor-investigator, L. Cinnamon Bidwell, University of Colorado, Boulder
- Investigators
- Timothy Curran, PhD, Principal investigator, University of Colorado, Boulder
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06669585
- Sponsor's protocol ID
- 20-0309: Experiment 3
- Other IDs
- R01DA052431
- Acronym
- COBRA 3
- Status last verified
- May 2026
- First submitted
- 23 Oct 2024
- Last updated
- 12 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 12 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Cannabis Observations on Brain Waves, Retrieval, and Attention: Experiment 3 (COBRA)
- ClinicalTrials.gov ID
- NCT06669585
- Acronym / sponsor ID
- COBRA 3 / 20-0309: Experiment 3
- Conditions
- Cannabis, Memory, Electroencephalography
- Keywords
- Cannabis, Memory, Electroencephalography
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 96 participants (actual)
- Lead sponsor
- L. Cinnamon BidwellUniversity, hospital or other
- Collaborators
- National Institute on Drug Abuse (NIDA)
- Study start
- 9 Oct 2024 (actual)
- Primary completion
- 10 Dec 2025 (actual)
- Study completion
- 10 Dec 2025 (actual)
- First posted
- 1 Nov 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study investigates the impact of ∆9-tetrahydrocannabinol (THC) and cannabidiol (CBD) on recognition memory in healthy, regular cannabis users. Participants complete the same recognition memory task after self-administering one of two different strains of cannabis flower one day and while not intoxicated another day. Event-related potentials (ERPs) are measured via electroencephalogram (EEG) during the recognition memory task. Blood is collected to quantify THC and CBD exposure. Participants also complete self-report measures of medical history, sleep quality, subjective cognitive function, physical activity, psychological functioning, substance use, and acute drug effects.
Detailed description
Previous research has established cannabis's harmful cognitive impact, with particularly robust and consistent effects in the domain of episodic memory. However, prior work has not sufficiently considered that the memory effects of cannabis are the compound action of different cannabinoids, which vary in their pharmacology and effects. Specifically, CBD, a non-psychotomimetic component of cannabis (doesn't produce a "high"), is thought to have cognitively protective properties and may mitigate some of the harmful effects of THC. Further, few prior studies have tested the effects of high potency strains that are commonly available.
This study tests the effects of commercially available cannabis flower strains on recognition memory performance and ERPs that are related to different underlying memory processes in healthy, regular cannabis users. An episodic memory task is used to assess recognition memory, which asks participants to discriminate between previously studied and non-studied items using pictures as stimuli. Participants complete the same memory task while intoxicated one day and not intoxicated another day. A THC-dominant strain and a strain containing both THC and CBD are included in the study. Participants self-administer one of the two cannabis strains prior to memory encoding and retrieval.
Blood is collected to determine THC and CBD exposure, as well as to explore how genetic variation in genes related to cannabinoid metabolism, cannabis-related behavior, and neurocognitive function associate with memory function before and after cannabis use. Participants also complete self-report measures of medical history, sleep quality, subjective cognitive function, physical activity, psychological functioning, substance use, and acute drug effects.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
Who may qualify
- Ages
- 21 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- Community sample of healthy, regular cannabis users in the Boulder and Denver areas
Key inclusion criteria (14 listed)
- Must be between the ages of 21 and 40 and provide informed consent;
- Must be right-handed (Laterality Quotient > 60 on Edinburgh Handedness Inventory - Short Form);
- Must use cannabis at least 4 days during the month;
- Must be a cannabis user for at least a year;
- Must self-report not using other illicit recreational drugs (e.g., cocaine, benzodiazepines (non-prescription), opiates (non-prescription), MDMA, sedatives, or methamphetamine) in the past 30 days, during the Pre-Screening;
Key exclusion criteria (0 listed)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Cannabis (smoked flower)Self-Directed Use (ad-libitum) | Drug | – |
Primary outcome
Difference in ERP amplitude (FN400)
Time frame: Intoxicated session and not-intoxicated session (about 1 week)
Electroencephalography is used to quantify FN400.
Difference in ERP amplitude (parietal)
Time frame: Intoxicated session and not-intoxicated session (about 1 week).
Electroencephalography is used to quantify parietal ERP effects.
Difference in retrieval memory accuracy
Time frame: Intoxicated session and not-intoxicated session (about 1 week)
Accuracy will be used to assess task performance.
Difference in retrieval memory performance
Time frame: Intoxicated session and not-intoxicated session (about 1 week)
Reaction time will be used to assess task performance.
8 secondary outcomes
Change in Positive and Negative Affect Schedule (PANAS)
Time frame: Before and after acute cannabis use during intoxicated session
Change in Drug Effects Questionnaire (DEQ)
Time frame: Before and after acute cannabis use during intoxicated session
Change in Addiction Research Center Inventory (ARCI-M)
Time frame: Before and after acute cannabis use during intoxicated session
Change in Marijuana Craving Questionnaire
Time frame: Before and after acute cannabis use during intoxicated session
Change in Profile of Mood States (POMS)
Time frame: Before and after acute cannabis use during intoxicated session
Change in Alcohol Craving Questionnaire
Time frame: Before and after acute cannabis use during intoxicated session
Change in State Adapted Paranoia Checklist-Brief (SAPC-B)
Time frame: Before and after acute cannabis use during intoxicated session
Difference in circulating cannabinoid concentration
Time frame: Baseline, intoxicated session, and not-intoxicated session (about 3 weeks total over all three sessions)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 May 2026.
- CUChange Study WebsiteLink provided by the sponsor.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Timothy Curran, PhD principal investigator
University of Colorado, Boulder
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Cannabis and Memory, run by L. Cinnamon Bidwell at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 14 inclusion and 0 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 12 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Difference in ERP amplitude (FN400) (time frame: Intoxicated session and not-intoxicated session (about 1 week)). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 May 2026.