The Effect of Cannabidiol in Learning and Memory of Adults

Phase 2

Completed

Conditions: Memory

Interventions: Drug: Placebo (246mg press pill)
Drug: Cannabidiol (246mg press pill)

Registration Number: NCT06074172

Lead Sponsor: Colorado State University

Brief Summary: 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.

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).

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 57

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 & Design

Study Type: INTERVENTIONAL

Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Placebo, Then Cannabidiol	Placebo (246mg press pill)	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.
Cannabidiol, Then Placebo	Cannabidiol (246mg press pill)	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.

Primary Outcome Measures

Name	Time	Method
Sum of Trials (I-V)	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.
Proactive Interference Ratio (PI Ratio)	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).
Retroactive Interference Ratio (RI Ratio)	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).
Total Prose Recall	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.
Montreal Cognitive Assessment Score	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.