The purpose of this study is:
* To investigate whether the response to antipsychotic treatment can be enhanced by adding cannabidiol (CBD) to the existing treatment, compared to placebo, in participants with a first episode of psychosis, who have had a suboptimal or no response to their first antipsychotic treatment.
* To confirm the safety of CBD in people with psychosis.
The study is a randomized, double-blind, placebo-controlled, multi-centre, clinical trial. Individuals with a diagnosis of first-episode psychosis, who have had a suboptimal or no response to their first antipsychotic treatment will be recruited. These participants are randomised to treatment with CBD oral solution 500mg twice daily, or a matching placebo for 6 weeks, as an adjunct to their existing antipsychotic treatment. By using a battery of clinical outcome assessments, the trial will also assess several biomarkers to determine if they can be used to predict clinical outcomes and response to treatment with CBD. Biomarkers are being assessed as an exploratory outcome measure. Participants will be invited to provide blood and stool samples, and may be asked to complete neuroimaging assessments at certain eligible sites.
Who can participate
Age range
16 Years – 40 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
. The participant is 16 to 40 years of age, willing and able to provide written informed consent/assent.
. The participant is currently being treated with an antipsychotic for at least 3 weeks but no longer than 16 weeks.
. The participant should be receiving at least the minimum dose of this antipsychotic for FEP according to modified Maudsley guidelines, as listed in Appendix B. The clinician should judge the participant to be a non-responder to this treatment and that increasing the dose further is unacceptable to the clinician and/or participant.
. The compliance score associated with this antipsychotic medication is 4 or more on the Clinician Rating Scale (CRS).
. The participant meets DSM-5 criteria for schizophrenia, schizoaffective disorder or schizophreniform disorder, as confirmed through the SCID-5-RV.
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Change in Positive and Negative Syndrome Scale (PANSS) total score
. The participant does not meet modified Andreasen criteria for symptomatic remission (time requirement does not apply).
. Participants of childbearing potential (\*) must be willing to ensure that they use highly effective contraception during the trial and as per the requirements in the protocol\*\*.
. In the Investigator's opinion, is able and willing to comply with all trial requirements.
Exclusion criteria
. Having been previously treated with a different antipsychotic (to the current one) at an adequate dose\* for 4 weeks or longer.
. Current or previous treatment with clozapine and/or current treatment with sodium valproate, valproate semisodium, or clobazam. In cases of current use of these medicines, participation is only permitted if they can and will be discontinued or switched to a suitable alternative medication prior to randomisation.
. Hypersensitivity to the active substance, sesame oil, sesame seed or any of the excipients of the intervention.
. Known hepatic insufficiency and/or transaminase elevations levels exceeding the upper limit of normal 2 times or more and bilirubin greater than 1.5 times the upper limit of normal.
. Previous neurosurgery or neurological disorder, including epilepsy, which may affect the study procedures\*\*.
. IQ \<70.
. Pregnancy or breastfeeding.
. The patient has a current diagnosis of 'Substance or medication induced psychotic disorder' or 'Psychotic disorder due to another medical condition' as determined through the SCID-5-RV.