Does Cannabidiol Attenuate the Acute Effects of ∆9-tetrahydrocannabinol Intoxication in Individuals Diagnosed With Schizophrenia? A Double-blind, Randomised, Placebo-controlled Experimental Study

NCT04605393 | Completed

• 1 other identifier: IRAS: 278595
• Study Type: interventional
• Target: 36
• Locations: 1 country
• Sites: 1

Brief Summary

This study will recruit schizophrenia patients who use cannabis recreationally. Each participant will attend the laboratory on three occasions: an initial visit to check that they are safe to join the study and two days of testing. Participants will be administered, in a randomized order, a pre-treatment with either CBD (1000mg) orally or a matching placebo. On both experiments, participants will then inhale cannabis containing THC. The THC 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.

Conditions

Schizophrenia; Cannabis Use

Outcome Measures

Primary Outcomes (2)

• Hopkins Verbal Learning Test

  Delayed verbal recall

  Baseline visit; 20 mins post-THC

• Positive and Negative Syndrome Scale

  Positive Subscale

  pre-CBD/placebo administration, and from immediately after THC inhalation until the end of study visit (i.e. 2-3 hours post-THC)

Secondary Outcomes (18)

• State-Trait Anxiety Inventory

  pre-CBD/placebo administration, pre-THC and 20mins post-THC

• Digit span

  Baseline; 25 mins post-THC

• Hopkins Verbal Learning Test

  Baseline; 20 mins post-THC

• Positive and Negative Syndrome Scale

  pre-CBD/placebo administration, and from immediately after THC inhalation until the end of study visit (i.e. 2-3 hours post-THC)

• Visual analogue scales

  pre-CBD/placebo, 90mins post CBD, pre-THC, and +10mins, +45mins, +90mins post-THC inhalation, and at the end of study visit (i.e. 2-3 hours post-THC)

Study Arms (2)

Placebo/THC

EXPERIMENTAL

Oral placebo followed by inhalation of cannabis containing THC.

Drug: Placebo; Drug: Delta-9-THC

CBD/THC

EXPERIMENTAL

Oral CBD 1000mg followed by inhalation of cannabis containing THC.

Drug: Cannabidiol; Drug: Delta-9-THC

Interventions

Cannabidiol DRUG

CBD

CBD/THC

Placebo DRUG

Placebo

Placebo/THC

Delta-9-THC DRUG

THC

CBD/THC; Placebo/THC

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age 18-65 years.
• Clinical diagnosis of schizophrenia (i.e. documented as such in the patient's clinical records and satisfying ICD-10 criteria for F20)
• Clinically stable for at least three months (since discharge from hospital, home treatment team, or prior clinical deterioration, and with agreement from the patient's responsible clinician)
• Regular (at least weekly) cannabis use for the past 3 months or more
• Evidence from either clinicians or from the patient that cannabis use exacerbates their symptoms or increases their risk of relapse
• Treatment with regular doses of antipsychotic medication for at least 1 month, confirmed by a blood test at the baseline visit, and with the participant agreeing to be maintained at a stable dose over the course of the experiment
• The participant agrees to abstain from cannabis use for at least 24hours prior to study visits
• The participant is willing to have an intravenous cannula inserted to collect blood samples on experimental visits
• Sufficiently fluent English
• Providing written informed consent

You may not qualify if:

• Extreme cannabis use: participant is estimate to be using over 1gram of cannabis/day
• Dependence on alcohol or illicit substances other than cannabis as defined by ICD-10
• Pregnancy (current or planned) or breastfeeding
• Physical health disorder or another mental health disorder that the study psychiatrist judges may influence the patient's ability to tolerate the procedure, or that may alter the results of the study.
• Taken part in any drug study within the last 3 months or taking part in another study over the course of the trial
• Drug sensitivity/allergy to cannabis or Lorazepam
• Unlikely to be able to complete the study sessions for any reason, as judged by the study psychiatrist
• Additional criteria which must be met on experimental visits:
• Negative alcohol breath test
• Negative urine drug screen (apart from cannabis and prescribed medication)
• Negative urine pregnancy test
• Stable mental state as judged by the study psychiatrist

Sponsors & Collaborators

• King's College London: lead

Study Sites (1)

South London and Maudsley NHS Foundation Trust

London, SE58AZ, United Kingdom

Location

Related Publications (1)

• Chesney E, Oliver D, Sarma A, Lamper AD, Slimani I, Lloyd M, Dickens AM, Welds M, Krakstrom M, Gasparini-Andre I, Oresic M, Lawn W, Babayeva N, Freeman TP, Englund A, Strang J, McGuire P. Does cannabidiol reduce the adverse effects of cannabis in schizophrenia? A randomised, double-blind, cross-over trial. Neuropsychopharmacology. 2025 Nov;50(12):1759-1767. doi: 10.1038/s41386-025-02175-3. Epub 2025 Jul 24.

  PMID: 40702165 DERIVED

MeSH Terms

Conditions

Schizophrenia

Interventions

Cannabidiol; Dronabinol

Condition Hierarchy (Ancestors)

Schizophrenia Spectrum and Other Psychotic Disorders; Mental Disorders

Intervention Hierarchy (Ancestors)

Cannabinoids; Terpenes; Hydrocarbons; Organic Chemicals

Study Officials

• Gill Dale

  slam-ioppn.research@kcl.ac.uk

  STUDY CHAIR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Psychiatrist/Clinical Research Fellow/Study Co-ordinator

Study Record Dates

• First Submitted: October 5, 2020
• First Posted: October 28, 2020
• Study Start: January 1, 2021
• Primary Completion: July 7, 2023
• Study Completion: July 7, 2023
• Last Updated: August 18, 2023

Record last verified: 2023-08

Data Sharing

• IPD Sharing: Will not share

Locations

GB (1)