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The main objectives of this study were to test if a singular dose of Cannabidiol (1) enhances the learning and memory of healthy human subjects, (2) test if Cannabidiol has negative effects on Retroactive and Proactive Interference during learning, (3) and test if demographic factors will influence CBD's modulation of human learning and memory.
Locally preserved from ClinicalTrials.govOpen ClinicalTrials.govlast source update 2025-03-24
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Results are reported by the registry submitter and preserved exactly. They are not independent verification or a treatment recommendation.
Registry facts
Using a randomized, double-blind, placebo-controlled two-arm case-crossover trial, this study investigates the effect of 246 milligrams (mg) of Cannabidiol (CBD) on the learning and memory scores of human subjects, as well as the effect of Cannabidiol on Proactive and Retroactive Interference. This study also investigated the influence of demographic factors on CBD's modulation of human learning and memory. This study was conducted at Colorado State University-Pueblo (CSU Pueblo) with volunteers recruited from CSU Pueblo and the local Pueblo community. Fifty-seven subjects were randomized in a double-blind manner to receive either CBD or placebo before completing two versions of learning and memory assessments. Each version of the learning and memory assessment included the Montreal Cognitive Assessment (MOCA), the Rey Auditory Verbal Learning Task-Revised (RAVLT-R), and the Logical Memory Subject of the Weschler Memory Scale. Several components of the RAVLT-R were evaluated including the Sum of Trials (Trials I-V) score, Proactive Interference Ratio (PI Ratio), and Retroactive Interference (RI Ratio).
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Local links use governed condition terms or exact source-reported intervention names. They are navigation candidates, not efficacy claims.
Interventions
Cannabidiol press pills provided by Steve Goods CBD (Longmont, Colorado). CBD pills were tested by the chemistry lab at CSU Pueblo and by Botanacor in Denver, CO. Both laboratories determined CBD pills to be 99.98% pure with no THC, heavy metals, bacteria, and pesticides detected.
Placebo press pills were provided by Steve Goods CBD (Longmont, Colorado). Placebo pills were tested by the chemistry lab at CSU Pueblo and by Botanacar in Denver, CO. Both laboratories determined placebo pills to be pure with no heavy metals, bacteria, and pesticides detected.
Source-reported results
Results are reported by the registry submitter and preserved exactly. They are not independent verification or a treatment recommendation.
Sum of Trials = Trial A1 + Trial A2 + Trial A3 + Trial A4 + Trial A5; Trial A1/A2/A3/A4/A5 are in reference to each trial in which list A is recalled during memory encoding. The score range for Sum of Trials is 0 to 75. A higher score is indicative of greater performance on the memory test and a lower score is indicative of lower performance on the memory test. Participants were instructed to listen to a list of 15 words (List A) read to them. Subjects were asked recall List A during five different trials (A1, A2, A3, A4, A5), with the words repeated to them after each trial. Participants were scored for the number of correctly repeated words for each trial.
Population: The data reported is for 35 adult healthy human subjects who came in for visits 1 and 2 and were randomized to a treatment group (CBD or placebo). Since the 35 subjects came in twice, each of them received both interventions (CBD and placebo).
| Group | N | Value | Spread / interval |
|---|---|---|---|
| Placebo (Administered During Visits 1 or 2) | 35 | 49.09 | 1.85 |
| Cannabidiol (Administered During Visits 1 or 2) | 35 | 47.17 | 1.85 |
Eligibility
primary outcomes
Time frame: Each trial is 45 seconds for encoding and recall
Sum of Trials = Trial A1 + Trial A2 + Trial A3 + Trial A4 + Trial A5; Trial A1/A2/A3/A4/A5 are in reference to each trial in which list A is recalled during memory encoding. The score range for Sum of Trials is 0 to 75. A higher score is indicative of greater performance on the memory test and a lower score is indicative of lower performance on the memory test. Participants were instructed to listen to a list of 15 words (List A) read to them. Subjects were asked recall List A during five different trials (A1, A2, A3, A4, A5), with the words repeated to them after each trial. Participants were scored for the number of correctly repeated words for each trial.
Time frame: Each trial is 45 seconds for encoding and recall
PI Ratio = Trial B1/A1. Proactive interference is the tendency for previously learned information to affect to hinder learning of new information. A higher proactive interference ratio indicates protective effects on memory i.e. protection from interference during learning. A lower proactive interference is indicative of negative effects on memory caused from interference. Trial A1 is in reference to list A recall during the first trial. Trial B1 is in reference to list B recall. Highest score for each trial is 15 with a point awarded for each correctly recalled word from List A (15 words) and List B (15 words).
Time frame: Each trial is 45 seconds for encoding and recall
RI Ratio = Trial A6/A5. Retroactive interference is the tendency for newly learned information to hinder the memory of previously learned information. A higher retroactive interference ratio indicates protection from interference during learning. A lower retroactive interference ratio is indicative of negative effects on memory caused from interference. Trial A6 is referring to delayed recall of list A; Trial A5 is referring to the fifth trial of list A recall. Highest score for each trial is 15 with a point awarded for each word correctly recalled from List A (15 words).
Time frame: Each recall takes about 5 min for encoding and recall
Total Prose Recall = Immediate Recall + Delayed Recall; Recall of a prose story was done immediately then after a delay; Highest score for prose recall test is 25 with a point awarded for each item correctly recalled in the story (25 total items). A higher recall score is indicative of better memory.
Publications
PI Ratio = Trial B1/A1. Proactive interference is the tendency for previously learned information to affect to hinder learning of new information. A higher proactive interference ratio indicates protective effects on memory i.e. protection from interference during learning. A lower proactive interference is indicative of negative effects on memory caused from interference. Trial A1 is in reference to list A recall during the first trial. Trial B1 is in reference to list B recall. Highest score for each trial is 15 with a point awarded for each correctly recalled word from List A (15 words) and List B (15 words).
Population: Adult healthy human subjects
| Group | N | Value | Spread / interval |
|---|---|---|---|
| Placebo (Visit 1 Drug Administration) | 35 | 1.04 | 0.08 |
| Cannabidiol (Visit 1 Drug Administration) | 35 | 1.21 | 0.08 |
RI Ratio = Trial A6/A5. Retroactive interference is the tendency for newly learned information to hinder the memory of previously learned information. A higher retroactive interference ratio indicates protection from interference during learning. A lower retroactive interference ratio is indicative of negative effects on memory caused from interference. Trial A6 is referring to delayed recall of list A; Trial A5 is referring to the fifth trial of list A recall. Highest score for each trial is 15 with a point awarded for each word correctly recalled from List A (15 words).
Population: Adult healthy human subjects
| Group | N | Value | Spread / interval |
|---|---|---|---|
| Placebo (Visit 1 Drug Administration) | 35 | 0.87 | 0.03 |
| Cannabidiol (Visit 1 Drug Administration) | 35 | 0.83 | 0.03 |
Total Prose Recall = Immediate Recall + Delayed Recall; Recall of a prose story was done immediately then after a delay; Highest score for prose recall test is 25 with a point awarded for each item correctly recalled in the story (25 total items). A higher recall score is indicative of better memory.
Population: Adult healthy human subjects
| Group | N | Value | Spread / interval |
|---|---|---|---|
| Placebo (Visit 1 Drug Administration) | 35 | 27.49 | 1.46 |
| Cannabidiol (Visit 1 Drug Administration) | 35 | 25.49 | 1.46 |
Assessment of basal cognitive function; The range for Montreal Cognitive Assessment (MOCA) scores is 0 to 30. A higher recall score is indicative of better performance on the memory test. A lower recall score is indicative of worse performance on the memory test.
Population: Adult healthy human population
| Group | N | Value | Spread / interval |
|---|---|---|---|
| Placebo (Visit 1 Drug Administration) | 35 | 26.31 | 0.46 |
| Cannabidiol (Visit 1 Drug Administration) | 35 | 26.63 | 0.46 |
| Milestone | Placebo (Visit 1 Drug Administration) | Cannabidiol (Visit 1 Drug Administration) |
|---|---|---|
| STARTED | 27 | 30 |
| COMPLETED | 21 | 23 |
| NOT COMPLETED | 6 | 7 |
| Event | System | Groups: affected / at risk |
|---|---|---|
| Drowsiness | Nervous system disorders | Placebo (Administered During Visits 1 or 2): 0 / 35 · Cannabidiol (Administered During Visits 1 or 2): 4 / 35 |
| Hunger | Gastrointestinal disorders | Placebo (Administered During Visits 1 or 2): 1 / 35 · Cannabidiol (Administered During Visits 1 or 2): 0 / 35 |
Time frame: 10 minutes total for encoding and recall
Assessment of basal cognitive function; The range for Montreal Cognitive Assessment (MOCA) scores is 0 to 30. A higher recall score is indicative of better performance on the memory test. A lower recall score is indicative of worse performance on the memory test.