Effect of Cannabidiol (CBD) on Vision and Driving
- Conditions
- Cannabis Use
- Interventions
- Other: Placebo (CBD 0%)Other: CBD 30%Other: CBD 15%
- Registration Number
- NCT06322303
- Lead Sponsor
- Universidad de Granada
- Brief Summary
The use of cannabis with ∆9-tetrahydrocannabinol (THC) content has been shown to have negative effects on vision and driving. The use of other cannabinoids, such as cannabidiol (CBD), which is not attributed with a psychoactive effect, is increasing significantly. This project aims to investigate whether consuming CBD can negatively affect visual function by assessing a wide range of visual parameters and whether these changes may pose a risk for everyday activities such as driving.
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- ACTIVE_NOT_RECRUITING
- Sex
- All
- Target Recruitment
- 60
- Being an occasional cannabis and/or cannabidiol user
- Have a current driving licence
- Have at least one year's driving experience
- Drive at least once a week
- Monocular visual acuity of at least 6/6 (Snellen) with habitual correction for driving
- Absence of binocular disorders
Exclusion criteria:
- Certain past or present medical conditions
- Current cannabis or alcohol use disorder
- Use of other drugs
- Pregnancy or lactation
- Simulator sickness.
Not provided
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- CROSSOVER
- Arm && Interventions
Group Intervention Description Placebo (CBD 0%) Placebo (CBD 0%) Participants are required to vaporize a placebo at 0% CBD concentration CBD 30% CBD 30% Participants are required to vaporize CBD at a concentration of 30%. CBD 15% CBD 15% Participants are required to vaporize CBD at a concentration of 15%.
- Primary Outcome Measures
Name Time Method Change in motion detection sensitivity after cannabidiol vaporization Participants are assessed 20 minutes after vaporization The subject has to indicate the direction of movement of a pattern of moving dots. The percentage of correct answers is obtained for different degrees of coherence.
Change in Overall Driving Performance Score (ODPS) after cannabidiol vaporization Participants are assessed 20 minutes after vaporization To obtain the ODPS, Z-scores were calculated from individual parameters such as the standard deviation of the lateral lane position or the distance travelled into the opposite lane. The z-score is defined as a measure of how many standard deviations an individual value is below or above the group mean. The average Z-score of the individual driving variables is called the ODPS.
Change in contrast sensitivity after cannabidiol vaporization Participants are assessed 20 minutes after vaporization Contrast thresholds are obtained for different spatial frequencies
Change in fixations after cannabidiol vaporization Participants are assessed 20 minutes after vaporization The number of fixations made on different stimuli of interest in a task environment is counted using an eye tracker system.
Change in visual acuity after cannabidiol vaporization Participants are assessed 20 minutes after vaporization Visual acuity is assessed with a commercial test for distance vision.
- Secondary Outcome Measures
Name Time Method Driving simulator: standard deviation of the lateral lane position (SDLP) Participants are assessed 20 minutes after vaporization Angular velocity of the steering wheel Participants are assessed 20 minutes after vaporization The angular velocity of the steering wheel is a metric that indicates the subject's ability to maintain the vehicle's position.
Distance travelled outside the lane Participants are assessed 20 minutes after vaporization The SDLP assesses the lane weaving that the subject performs in the lane and indicates whether the vehicle's position is consistent.
Mean speed Participants are assessed 20 minutes after vaporization Average speed is obtained and analyzed in relation to the speed limits for different sections.
Trial Locations
- Locations (1)
University of Granada
🇪🇸Granada, Spain