CannabisCOBRA 4NCT07679581
Cannabis Observations on Brain Waves, Retrieval, and Attention: Experiment 4
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
- 64 participants
- Where
- 1 siteUnited States
- Study dates
- 10 Dec 2025to 31 May 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
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/Denver areas.
- 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 Form136);
- Heavy users (HU) in Experiments 1, 2, 3, and 4:
- Must use cannabis at least 4 days during the month;
- Must be a cannabis user for at least a year;
- Non-users (NU) in Experiment 2:
- Must not have used cannabis for prior 6 months;
- Must have at least one episode of lifetime cannabis use;
- 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 (TDS);
- 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; ADHD medications, even extended-release forms, are short acting and medication" holidays" (e.g., on weekends and holidays) are routine in individuals prescribed ADHD medications, without adverse effects.
- 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;
- Must have a breath alcohol level of 0 at screening (to sign consent form);
- Must not be actively seeking or in treatment for any substance use disorder (drug use levels will be carefully monitored via Timeline Follow Back (TLFB) throughout the study to assess any confounding influences of drug or alcohol use;
- Female subjects must not be or trying to become pregnant (as indicated by a pregnancy test \& screening form administered at Baseline);
- 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.
- Participants in Experiment 4 a. Must not have participated in Experiment 3
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Center for Innovation and Creativity (CINC)
Boulder, Colorado, 80301
Katie N Paulich, Ph.D., 303-492-9549, cobra.custudy@gmail.com
Timothy Curran, Ph.D.
About this study
Official title: Cannabis and Memory
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)
The FN400 event-related potential (ERP) old/new effect will be measured using electroencephalography (EEG) during a recognition memory test. The FN400 reflects familiarity-based memory retrieval and is defined as the mean ERP amplitude difference between correctly recognized previously presented items ("hits") and correctly rejected novel items ("correct rejections") at mid-frontal electrode sites during the 300-500ms post-stimulus interval.
Measured: Intoxicated session and not-intoxicated session (about 1 week)
Difference in ERP amplitude (parietal)
The parietal ERP old/new effect will be measured using EEG during a recognition memory test. The parietal old/new effect reflects recollection-based memory retrieval and is defined as the mean ERP amplitude difference between hits and correct rejections at parietal electrode sites during the 500-800ms post-stimulus interval.
Measured: Intoxicated session and not-intoxicated session (about 1 week)
Difference in retrieval memory accuracy
Behavioral accuracy during recognition memory test will be assessed by the number of hits and correct rejections made during memory recall. Retrieval memory accuracy will be compared between intoxicated and not-intoxicated sessions.
Measured: Intoxicated session and not-intoxicated session (about 1 week)
Difference in retrieval memory performance
Memory performance will be assessed via reaction time, measured by a photocell during recognition memory testing and concurrent EEG. During the recall phase, a light indicator will appear in the bottom-right corner of the stimulus screen when a prompted image is presented, activating the photocell. This indicator disappears once the participant responds. The interval between stimulus onset and the participant's "new" or "old" response is used as the reaction time measure for both intoxicated and non-intoxicated sessions. Retrieval memory performance will be compared between intoxicated and not-intoxicated sessions.
Measured: Intoxicated session and not-intoxicated session (about 1 week)
Secondary outcomes (8)
Change in Positive and Negative Affect Schedule (PANAS)
The PANAS is a Self-report measurement of positive and negative affect that will be administered at all times of the Mobile sessions: the pre-use and post-use timepoints of the intoxicated session, well as the not-intoxicated session. The PANAS will be used twice at the intoxicated session to measure changes in mood before and after cannabis use. The survey presents a 20-item scale from 1 (very slightly or not at all) to 5 (extremely), 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: During a single non-intoxicated laboratory session and immediately before and immediately after acute cannabis use during a single intoxicated laboratory session
Change in Drug Effects Questionnaire (DEQ)
The DEQ is a 5-item visual analogue scale that measures acute drug effects, with prevalent use across numerous drug studies. Specifically, the questionnaire measures strength of the effects of cannabis as well as the desirability of the effects. Participants answer questions on a range from 0 - 100, with higher values for each item indicating greater drug effect or desire. The specific items related to drug "liking" and "wanting more" have been associated with harmful drug use. Participants will be administered the DEQ at all time points of the Mobile sessions to assess differences following intoxication.
Measured: During a single non-intoxicated laboratory session and immediately before and immediately after acute cannabis use during a single intoxicated laboratory session
Change in Addiction Research Center Inventory (ARCI-M)
The ARCI-M is a self-report measure of subjective effects of marijuana in addition to drug-induced euphoria, stimulant-like effects, intellectual efficiency and energy, sedation, dysphoria, and other somatic effects. This is a 12 item true-false task, in which higher (true) scores indicate greater intoxication. Participants will be administered the ARCI-M at all time points of the Mobile sessions to assess differences following intoxication.
Measured: During a single non-intoxicated laboratory session and immediately before and immediately after acute cannabis use during a single intoxicated laboratory session
Change in Marijuana Craving Questionnaire (MCQ)
The Marijuana Craving Questionnaire is a self-report measure of marijuana craving that will be administered at all time points during the Mobile sessions. Participants complete 8 questions ranging from 0 - 10, with a higher score indicating greater cannabis craving and somatic symptoms. The primary focus of this questionnaire will be the effect of intoxication on reporting.
Measured: During a single non-intoxicated laboratory session and immediately before and immediately after acute cannabis use during a single intoxicated laboratory 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. The POMS will be administered at all time points of the Mobile sessions, in order to measure changes in mood before and after intoxication.
Measured: During a single non-intoxicated laboratory session and immediately before and immediately after acute cannabis use during a single intoxicated laboratory session
Change in Alcohol Craving Questionnaire (ACQ)
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. The ACQ is used at all time points of the Mobile sessions.
Measured: During a single non-intoxicated laboratory session and immediately before and immediately after acute cannabis use during a single intoxicated laboratory 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. The SAPC-B is administered at all time points of the Mobile sessions to assess changes in paranoia after intoxication.
Measured: During a single non-intoxicated laboratory session and immediately before and immediately after acute cannabis use during a single intoxicated laboratory session
Difference in circulating cannabinoid concentration
Participants use cannabis ad-libitum. Therefore, blood levels of THC and CBD will be used to quantify dosage and compared across the not-intoxicated, pre-use and post-use time points of the Mobile sessions. This further allows for a direct test of whether any differences in outcomes for participants randomly assigned to the -THC/+CBD strain are due to an increase in CBD or a decrease in THC as compared to their baseline.
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 Jul 2026
- Study start10 Dec 2025
- Primary completion1 Feb 2027 (estimated)
- Study completion31 May 2027 (estimated)
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
- 64 participants (estimated)
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, Ph.D., Principal investigator, University of Colorado, Boulder
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07679581
- Sponsor's protocol ID
- 20-0309: Experiment 4
- Other IDs
- R01DA052431
- Acronym
- COBRA 4
- Status last verified
- Jun 2026
- First submitted
- 18 Jun 2026
- Last updated
- 1 Jul 2026
- Results posted
- 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 1 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Cannabis and Memory
- ClinicalTrials.gov ID
- NCT07679581
- Acronym / sponsor ID
- COBRA 4 / 20-0309: Experiment 4
- Conditions
- Cannabis, Memory, Electroencephalography
- Keywords
- Cannabis, Memory, Electroencephalography
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 64 participants (estimated)
- Lead sponsor
- L. Cinnamon BidwellUniversity, hospital or other
- Collaborators
- National Institute on Drug Abuse (NIDA)
- Study start
- 10 Dec 2025 (actual)
- Primary completion
- 1 Feb 2027 (estimated)
- Study completion
- 31 May 2027 (estimated)
- First posted
- 1 Jul 2026 (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/Denver areas.
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)
The FN400 event-related potential (ERP) old/new effect will be measured using electroencephalography (EEG) during a recognition memory test. The FN400 reflects familiarity-based memory retrieval and is defined as the mean ERP amplitude difference between correctly recognized previously presented items ("hits") and correctly rejected novel items ("correct rejections") at mid-frontal electrode sites during the 300-500ms post-stimulus interval.
Difference in ERP amplitude (parietal)
Time frame: Intoxicated session and not-intoxicated session (about 1 week)
The parietal ERP old/new effect will be measured using EEG during a recognition memory test. The parietal old/new effect reflects recollection-based memory retrieval and is defined as the mean ERP amplitude difference between hits and correct rejections at parietal electrode sites during the 500-800ms post-stimulus interval.
Difference in retrieval memory accuracy
Time frame: Intoxicated session and not-intoxicated session (about 1 week)
Behavioral accuracy during recognition memory test will be assessed by the number of hits and correct rejections made during memory recall. Retrieval memory accuracy will be compared between intoxicated and not-intoxicated sessions.
Difference in retrieval memory performance
Time frame: Intoxicated session and not-intoxicated session (about 1 week)
Memory performance will be assessed via reaction time, measured by a photocell during recognition memory testing and concurrent EEG. During the recall phase, a light indicator will appear in the bottom-right corner of the stimulus screen when a prompted image is presented, activating the photocell. This indicator disappears once the participant responds. The interval between stimulus onset and the participant's "new" or "old" response is used as the reaction time measure for both intoxicated and non-intoxicated sessions. Retrieval memory performance will be compared between intoxicated and not-intoxicated sessions.
8 secondary outcomes
Change in Positive and Negative Affect Schedule (PANAS)
Time frame: During a single non-intoxicated laboratory session and immediately before and immediately after acute cannabis use during a single intoxicated laboratory session
Change in Drug Effects Questionnaire (DEQ)
Time frame: During a single non-intoxicated laboratory session and immediately before and immediately after acute cannabis use during a single intoxicated laboratory session
Change in Addiction Research Center Inventory (ARCI-M)
Time frame: During a single non-intoxicated laboratory session and immediately before and immediately after acute cannabis use during a single intoxicated laboratory session
Change in Marijuana Craving Questionnaire (MCQ)
Time frame: During a single non-intoxicated laboratory session and immediately before and immediately after acute cannabis use during a single intoxicated laboratory session
Change in Profile of Mood States (POMS)
Time frame: During a single non-intoxicated laboratory session and immediately before and immediately after acute cannabis use during a single intoxicated laboratory session
Change in Alcohol Craving Questionnaire (ACQ)
Time frame: During a single non-intoxicated laboratory session and immediately before and immediately after acute cannabis use during a single intoxicated laboratory session
Change in State Adapted Paranoia Checklist-Brief (SAPC-B)
Time frame: During a single non-intoxicated laboratory session and immediately before and immediately after acute cannabis use during a single intoxicated laboratory 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
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 Jul 2026.
- CU Change 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.
Timothy Curran, Ph.D. 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?
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: looking for participants now, as of the sponsor's last update on 1 Jul 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Katie N Paulich, Ph.D. (303-492-9549, cobra.custudy@gmail.com), or a site near the patient. 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 1 Jul 2026.