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AzTrials

SchizophreniaINTEGRATENCT04605393

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

A study testing Cannabidiol and Delta-9-THC in people with Schizophrenia and Cannabis Use, run by King's College London at 1 site in United Kingdom.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial 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. Read more about this study

Who is it for?
Ages 18 to 65 years
Conditions the study is for
Schizophrenia, Cannabis Use
What is being tested?
Cannabidiol and Delta-9-THC
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
36 participants
Where
1 siteUnited Kingdom
Study dates
1 Jan 2021to 7 Jul 2023
Phase
Interventional
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 65 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • 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
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  • 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

Who cannot join

  • 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
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  • 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

Trial locations and contacts

1 site in 1 country.

United Kingdom1 site

  • South London and Maudsley NHS Foundation Trust

    London, SE58AZ

Other trials in United Kingdom

About this 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.

Read more

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.

Being tested
Cannabidiol, Placebo, Delta-9-THC
Medical subject headings
Schizophrenia

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • CannabidiolDrug

    CBD

  • PlaceboDrug

    Placebo

  • Delta-9-THCDrug

    THC

Study groups in NCT04605393
Study groupRoleWhat they receive
Placebo/THCExperimentalOral placebo followed by inhalation of cannabis containing THC.
Receives: Drug: Placebo; Drug: Delta-9-THC
CBD/THCExperimentalOral CBD 1000mg followed by inhalation of cannabis containing THC.
Receives: Drug: Cannabidiol; Drug: Delta-9-THC

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Hopkins Verbal Learning Test

    Delayed verbal recall

    Measured: Baseline visit; 20 mins post-THC

  2. Positive and Negative Syndrome Scale

    Positive Subscale

    Measured: 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)

  1. State-Trait Anxiety Inventory

    State Scale

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

  2. Digit span

    Forward \& Reverse

    Measured: Baseline; 25 mins post-THC

  3. Hopkins Verbal Learning Test

    Immediate verbal recall

    Measured: Baseline; 20 mins post-THC

  4. Positive and Negative Syndrome Scale

    Negative Subscale

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

  5. Visual analogue scales

    • 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

    Measured: 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)

  6. Psychotomimetic states inventory

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

  7. State Social Paranoia Scale

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

  8. Study drug preference

    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.

    Measured: End of Experiment 2

  9. Advice Taking Task

    Measured: Baseline visit; 30 mins post-THC

  10. White Noise Task

    Measured: Baseline visit; 50 mins post-THC

  11. Plasma delta-9-tetrahydrocannabinol (THC) concentration

    Measured: pre-CBD/placebo, 90mins post CBD, and 0mins, 5mins, 15mins, +90mins post-THC

  12. Plasma cannabidiol (CBD) concentration

    Measured: pre-CBD/placebo, 90mins post CBD, and 0mins, 5mins, 15mins, +90mins post-THC

  13. Plasma THC-COOH concentraion

    Measured: pre-CBD/placebo, 90mins post CBD, and 0mins, 5mins, 15mins, +90mins post-THC

  14. Plasma 11-COOH-THC concentration

    Measured: pre-CBD/placebo, 90mins post CBD, and 0mins, 5mins, 15mins, +90mins post-THC

  15. Plasma 11-OH-THC concentration

    Measured: pre-CBD/placebo, 90mins post CBD, and 0mins, 5mins, 15mins, +90mins post-THC

  16. Plasma 6-OH-CBD concentration

    Measured: pre-CBD/placebo, 90mins post CBD, and 0mins, 5mins, 15mins, +90mins post-THC

  17. Plasma anandamide concentration

    Measured: pre-CBD/placebo, 90mins post CBD, and 0mins, 5mins, 15mins, +90mins post-THC

  18. Plasma 2-arachidonoylglycerol concentration.

    Measured: pre-CBD/placebo, 90mins post CBD, and 0mins, 5mins, 15mins, +90mins post-THC

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted28 Oct 2020
  2. Study start1 Jan 2021
  3. Primary completion7 Jul 2023
  4. Study completion7 Jul 2023

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Basic science
Allocation
Randomised
Intervention model
Crossover
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
36 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04605393
Sponsor's protocol ID
IRAS: 278595
Acronym
INTEGRATE
Status last verified
Aug 2023
First submitted
5 Oct 2020
Last updated
18 Aug 2023
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Publications

  • 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.

    PubMed 40702165

Questions about this trial

What is this clinical trial studying?

A study testing Cannabidiol and Delta-9-THC in people with Schizophrenia and Cannabis Use, run by King's College London at 1 site in United Kingdom.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 10 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 18 Aug 2023. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Hopkins Verbal Learning Test (time frame: Baseline visit; 20 mins post-THC). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04605393, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Aug 2023.

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