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Completed

NCT Number: NCT05170217

Reducing the Harmful Effects of Cannabis Use: Finding the Optimal CBD:THC Ratio

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.

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Key information

Conditions

Cannabis Use

Age range

21 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Institute of Psychiatry, Psychology and Neuroscience, King's College London

London, SE5 8AF, United Kingdom

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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

Exclusion criteria

  • 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

Treatment and study plan

THC

Drug

Inhaled cannabis containing 10mg THC

Cannabidiol

Drug

Inhaled cannabis containing 10mg CBD

Primary outcomes

  1. Hopkins Verbal Learning Task

    Time frame: 40-45 minutes post cannabis inhalation

    Delayed verbal recall

Secondary outcomes

  1. Hopkins Verbal Learning Task

    Time frame: 20-40 minutes post cannabis inhalation

    Immediate verbal recall

  2. Forward and Reverse Digit span

    Time frame: 20-40 minutes post cannabis inhalation

    Working memory

  3. Spatial N-back task

    Time frame: 20-40 minutes post cannabis inhalation

    Spatial working memory

  4. Positive and Negative Syndrome Scale

    Time frame: Baseline; 3-4 hours post cannabis inhalation

    Positive subscale

  5. State Social Paranoia Scale

    Time frame: 3-4 hours post cannabis inhalation

  6. Community assessment of Psychic Experiences - state

    Time frame: 3-4 hours post cannabis inhalation

  7. Psychotomimetic states inventory

    Time frame: 3-4 hours post cannabis inhalation

  8. Visual analogue scales (0 to 100 millimetres)

    Time frame: 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 pleasurable

  9. Pleasurable responses - Visual analogue scale (-50 to 50 millimetres)

    Time frame: 1 hour post-cannabis

    Increased or decreased pleasure from chocolate and music during intoxication

  10. Plasma THC concentration

    Time frame: Pre-cannabis, 0 minutes post-cannabis, 5 minutes post-cannabis, 15 minutes post-cannabis, 90 minutes post-cannabis

  11. Plasma CBD concentration

    Time frame: Pre-cannabis, 0 minutes post-cannabis, 5 minutes post-cannabis, 15 minutes post-cannabis, 90 minutes post-cannabis

  12. Plasma 11-OH-THC concentration

    Time frame: Pre-cannabis, 0 minutes post-cannabis, 5 minutes post-cannabis, 15 minutes post-cannabis, 90 minutes post-cannabis

  13. Plasma 11-COOH-THC concentration

    Time frame: Pre-cannabis, 0 minutes post-cannabis, 5 minutes post-cannabis, 15 minutes post-cannabis, 90 minutes post-cannabis

  14. Plasma 7-OH-CBD concentration

    Time frame: Pre-cannabis, 0 minutes post-cannabis, 5 minutes post-cannabis, 15 minutes post-cannabis, 90 minutes post-cannabis

Sponsors and collaborators

Lead sponsor

King's College London

Other

Registry information

Acronym: eCBD

Important dates

Study start
2017
Primary completion
2019
Study completion
2019
First posted
Dec 27, 2021
Registry last updated
Dec 27, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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