The Effect of Cannabidiol in Learning and Memory of Adults

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.

Study Overview

• Status: Completed
• Conditions: Memory
• Intervention / Treatment: Drug: Placebo (246mg press pill); Drug: Cannabidiol (246mg press pill)

Detailed Description

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).

• Study Type: Interventional
• Enrollment (Actual): 57
• Phase: Phase 2

Contacts and Locations

Study Locations

• United States
  • Colorado
    • Pueblo, Colorado, United States, 81001
      • Colorado State University Pueblo

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Were 18 years of age or older

Exclusion Criteria:

• Were pregnant or breast-feeding
• Had been diagnosed with mental illness
• Didn't speak English fluently
• Had severe hearing problems
• Had recreational or opioid drug contaminants in their urine
• Were involved in criminal activity

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo, Then Cannabidiol; Participants first received a Placebo 246 mg press pill during visit 1. After a washout period of 1 week, subjects received a Cannabidiol press pill during visit 2.	Drug: Placebo (246mg press pill); 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.
Active Comparator: Cannabidiol, Then Placebo; Participants first received a Cannabidiol 246 mg press pill during visit 1. After a washout period of 1 week, subjects received a Placebo press pill during visit 2.	Drug: Cannabidiol (246mg press pill); 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proactive Interference Ratio (PI Ratio)	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).	Each trial is 45 seconds for encoding and recall
Retroactive Interference Ratio (RI Ratio)	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).	Each trial is 45 seconds for encoding and recall
Total Prose 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.	Each recall takes about 5 min for encoding and recall
Sum of Trials (I-V)	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.	Each trial is 45 seconds for encoding and recall
Montreal Cognitive Assessment Score	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.	10 minutes total for encoding and recall

Collaborators and Investigators

• Sponsor: Colorado State University
• Collaborators: Institute of Cannabis Research
• Investigators: Principal Investigator: Moussa M Diawara, PhD, Colorado State University-Pueblo

Study record dates

Study Major Dates

• Study Start (Actual): March 14, 2020
• Primary Completion (Actual): November 6, 2020
• Study Completion (Actual): November 6, 2020

Study Registration Dates

• First Submitted: September 26, 2023
• First Submitted That Met QC Criteria: October 5, 2023
• First Posted (Actual): October 10, 2023

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: March 19, 2025
• Last Verified: March 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Anticonvulsants; Cannabidiol
• Other Study ID Numbers: MD012420BM

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Individual (de-identified) participant data is to be made available to other researchers.
• IPD Sharing Time Frame: Data will become available upon request.
• IPD Sharing Access Criteria: Data will become available upon request.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes