INTERVENTIONALCOMPLETEDNCT04605393

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

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.

Locally preserved from ClinicalTrials.govOpen ClinicalTrials.govlast source update 2023-08-18

What this record can show

Protocol only - no registry results posted

This locally preserved record separates the registered protocol from source-reported registry results. Neither is a treatment recommendation.

Registry facts

Study at a glance

Phase: NA
Enrollment: 36 (ACTUAL)
Start date: 2021-01-01
Sponsor: King's College London
Design: RANDOMIZED · CROSSOVER · BASIC SCIENCE
Locations: 1
Results record: Not present in registry snapshot

Linked local records

Related local records

Local links use governed condition terms or exact source-reported intervention names. They are navigation candidates, not efficacy claims.

Conditions

No published condition report matched.

Cannabinoids and active compounds

cannabidiol Delta(9)-tetrahydrocannabinol

Medicines

No exact medicine-name link was found.

Research network

Researchers and organizations

Alex Dickens Amir Englund A. V. S. Sarma Ayşe Doğa Lamper Dominic Oliver Edward Chesney Ikram Slimani Irma Gasparini-Andre John Strang Matej Oresic

Population and criteria

Sex

ALL

Minimum age

18 Years

Maximum age

65 Years

Healthy volunteers

Not accepted

Inclusion criteria

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

Exclusion criteria

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

secondary measures

State-Trait Anxiety Inventory

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

State Scale

Digit span

Time frame: Baseline; 25 mins post-THC

Forward \& Reverse

Hopkins Verbal Learning Test

Time frame: Baseline; 20 mins post-THC

Immediate verbal recall

Positive and Negative Syndrome Scale

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

Negative Subscale

Visual analogue scales

Time frame: 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)

* Feel drug effect * Like drug effect * Want more drug * Thinking clearly * Tired * Excited * Want to talk * Anxious * Relaxed * Happy * Irritable * Suspicious * Hearing voices * Dry mouth * Hungry

Psychotomimetic states inventory

Time frame: pre-CBD/placebo administration, and at the end of study visit (i.e. 2-3 hours post-THC)

State Social Paranoia Scale

Time frame: pre-CBD/placebo administration, and at the end of study visit (i.e. 2-3 hours post-THC)

Study drug preference

Time frame: End of Experiment 2

At the end of the final experimental visit (i.e. 2-3 hours post-THC), participants will be asked to order the two experimental visits according to which drug combination they found most pleasurable.

Advice Taking Task

Time frame: Baseline visit; 30 mins post-THC