Reducing the Harmful Effects of Cannabis Use: Finding the Optimal CBD:THC Ratio
- Registration Number
- NCT05170217
- Lead Sponsor
- King's College London
- Brief Summary
This study will recruit healthy volunteers who use cannabis infrequently. Each participant will attend the laboratory on five occasions: an initial visit to check that they are safe to join the study and four days of testing.
Participants will be administered, in a randomized order, vaporized cannabis containing one of four different ratios of CBD:THC (0:1, 1:1, 2:1, 3:1). The cannabis administration will follow a standardised inhalation procedure using a medical-grade vaporizer device.
Participants will complete a series of tasks measuring cognition, psychosis, anxiety and other subjective experiences.
The study will be carried out at the NIHR-Wellcome Trust Clinical Research Facility at King's College Hospital.
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 46
- Female and male volunteers aged 21-50
- Have used cannabis at least once
- Willing to provide written informed consent
- Willing to provide blood samples
- Fluent English speaker
- Past or present major mental illness
- Past or present major physical illness
- Past or present substance use disorder
- Past or present use of anti-psychotic or anti-depressant medications
- First degree relative with psychotic disorder
- Currently taking psychotropic medication
- Positive urine drug screen at screening or experimental visits
- Use of alcohol 24h prior to experimental visit or tobacco on the day of experiment
- Pregnancy (current or planned) or lactation in women
- Significant abnormality detected during physical examination at screening visit
- Cannabis use (defined as days in which cannabis is used recreationally) more than once per week on average over the last 12 months
- Any past use of synthetic cannabinoids
- Score of 5 and above on the Fagerstrom Nicotine dependence questionnaire
- BMI classified as obese or underweight
- Taken part in any drug study within the last 30 days or taking part in another study over the course of the trial
- Known drug sensitivity/allergy towards cannabis or Lorazepam
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- CROSSOVER
- Arm && Interventions
Group Intervention Description CBD:THC 2:1 THC Inhalation of cannabis containing THC and CBD CBD:THC 2:1 Cannabidiol Inhalation of cannabis containing THC and CBD CBD:THC 0:1 THC Inhalation of cannabis containing only THC CBD:THC 1:1 Cannabidiol Inhalation of cannabis containing THC and CBD CBD:THC 1:1 THC Inhalation of cannabis containing THC and CBD CBD:THC 3:1 THC Inhalation of cannabis containing THC and CBD CBD:THC 3:1 Cannabidiol Inhalation of cannabis containing THC and CBD
- Primary Outcome Measures
Name Time Method Hopkins Verbal Learning Task 40-45 minutes post cannabis inhalation Delayed verbal recall
- Secondary Outcome Measures
Name Time Method Hopkins Verbal Learning Task 20-40 minutes post cannabis inhalation Immediate verbal recall
Spatial N-back task 20-40 minutes post cannabis inhalation Spatial working memory
Pleasurable responses - Visual analogue scale (-50 to 50 millimetres) 1 hour post-cannabis Increased or decreased pleasure from chocolate and music during intoxication
Plasma THC concentration Pre-cannabis, 0 minutes post-cannabis, 5 minutes post-cannabis, 15 minutes post-cannabis, 90 minutes post-cannabis Forward and Reverse Digit span 20-40 minutes post cannabis inhalation Working memory
Community assessment of Psychic Experiences - state 3-4 hours post cannabis inhalation Plasma 11-OH-THC concentration Pre-cannabis, 0 minutes post-cannabis, 5 minutes post-cannabis, 15 minutes post-cannabis, 90 minutes post-cannabis Plasma 11-COOH-THC concentration Pre-cannabis, 0 minutes post-cannabis, 5 minutes post-cannabis, 15 minutes post-cannabis, 90 minutes post-cannabis Plasma 7-OH-CBD concentration Pre-cannabis, 0 minutes post-cannabis, 5 minutes post-cannabis, 15 minutes post-cannabis, 90 minutes post-cannabis Positive and Negative Syndrome Scale Baseline; 3-4 hours post cannabis inhalation Positive subscale
State Social Paranoia Scale 3-4 hours post cannabis inhalation Psychotomimetic states inventory 3-4 hours post cannabis inhalation Visual analogue scales (0 to 100 millimetres) Baseline; Pre-cannabis, 10 minutes post-cannabis, 50 minutes post-cannabis, 1 hour 10 minutes post-cannabis, discharge * Feel drug effect
* Like drug effect
* Want more drug
* Mentally impaired
* Dry Mouth
* Enhanced colour perception
* Enhanced sound perception
* Want food
* Want alcohol
* Feel high
* Feel anxious
* Feel paranoid
* Feel tired
* Feel calm and relaxed
* Feel stoned
* The drug effects are pleasurablePlasma CBD concentration Pre-cannabis, 0 minutes post-cannabis, 5 minutes post-cannabis, 15 minutes post-cannabis, 90 minutes post-cannabis
Trial Locations
- Locations (1)
Institute of Psychiatry, Psychology and Neuroscience, King's College London
🇬🇧London, United Kingdom