Effects of Cannabidiol (CBD) Versus Placebo as an Adjunct to Treatment in Early Psychosis

NCT ID: NCT04411225

Last Updated: 2026-01-08

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: PHASE3
• Total Enrollment: 120 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-06-01
• Study Completion Date: 2026-12-31

Brief Summary

This is an outpatient, single center, between-group, double blind, placebo controlled design. Approximately 120 adolescents and adult patients will be randomized to either have their treatment augmented with Cannabidiol Oral Solution (CBD) or with a matching CBD placebo for 8 weeks. The study will examine CBD as an augmentation strategy in early psychosis. It is hypothesized that CBD will improve symptoms, neurocognition, markers of inflammation and eating behaviors. Importantly, moderators and mediators of the CBD effects will be explored.

Detailed Description

Participants will be randomly assigned in a 1:1 ratio to receive CBD or matching Placebo as an add-on to antipsychotic medication in an 8 week double blind trial. In this study, Cannabidiol Oral Solution (CBD) product will be used. This product is manufactured and supplied by GW Pharmaceuticals. The formulation is a 100 mg/mL solution. The CBD compound will be dosed at 1000mg/day administered in two divided doses. The dose of CBD was selected based on previous controlled trials that demonstrate the efficacy of CBD in patients with schizophrenia.

The maximum duration of the study from screening to follow up of outcomes and adverse events will be approximately 8 weeks. Participants will receive either the CBD or placebo within this eight.weeks and will also complete pre-treatment, midpoint (week 4) and post-treatment testing (week 8).

Conditions

Early Psychosis

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: QUADRUPLE

Study Groups

Cannabidiol Augmentation

The cannabidiol will be administered as an oral solution to be mixed in any fluid. The formulation is 100 mg/ml. It will be administered at 500 mg at bedtime X 1 week then 500 mg BID.

Group Type: EXPERIMENTAL

Cannabidiol oral solution

Intervention Type: DRUG

Both the active drug (cannabidiol) and placebo will be in oral solution.

Placebo Augmentation

Placebo will appear identical to the cannabidiol solution

Group Type: PLACEBO_COMPARATOR

Cannabidiol oral solution

Intervention Type: DRUG

Both the active drug (cannabidiol) and placebo will be in oral solution.

Interventions

Cannabidiol oral solution

Both the active drug (cannabidiol) and placebo will be in oral solution.

Intervention Type: DRUG

Other Intervention Names

Placebo

Eligibility Criteria

Inclusion Criteria

• First episode psychosis (onset within the last 2 years) or attenuated psychosis syndrome (APS), stabilized with treatment for at least 8 weeks prior to initiating the trial consistent with the FDA-NIMH-MATRICS guidelines for clinical trial design for clinical enhancing drugs:
• Clinically stable and in a nonacute phase of their illness for at least 2 months, First episode psychosis participants will have been maintained on current antipsychotic for at least 6 weeks, with no change in antipsychotic dose for the previous 4 weeks while APS participants will be on the same treatment regimen (psychosocial or pharmacologic) for 4 weeks,
• Exhibit no more than moderate levels of positive symptoms (defined by ratings of ≤ 4) on PANSS items P1 (delusions), P2 (conceptual disorganization), P3 (hallucinatory behavior), P5 (grandiosity), P6 (suspiciousness), and G8 (unusual thought content),
• No more than a minimal level of depressive symptoms as assessed by the Calgary Depression Scale for Schizophrenia (CDSS)
• Acceptable diagnoses will include APS, Psychosis NOS, Schizophreniform, Schizophrenia, and Schizoaffective per the Structured Clinical Interview for DSM-V.

Exclusion Criteria

• Concomitant medical or neurological illness;
• Significant head injury;
• Impaired intellectual functioning IQ<80; however those with an IQ i the 75-79 range will be include if WRAT reading > 85 suggesting higher premorbid IQ.
• High suicidal risk assessed by the The Columbia-Suicide Severity Rating Scale (C-SSRS)42
• Pregnant women and those who do not agree to avoid becoming pregnant
• Patients requiring treatment with Azelastine, Azelastine; Fluticasone, Dronabinol, Valproic Acid, or Divalproex Sodium

• Minimum Eligible Age: 16 Years
• Maximum Eligible Age: 30 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Center for Medicinal Cannabis Research

OTHER

Sponsor Role: collaborator

University of California, San Diego

OTHER

Sponsor Role: lead

Responsible Party

Kristin Cadenhead, M.D.

Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Kristin Cadenhead, MD

Role: PRINCIPAL_INVESTIGATOR

University of California, San Diego

Locations

UC San Diego

La Jolla, California, United States

Site Status: RECRUITING

University of California, San Diego

San Diego, California, United States

Site Status: RECRUITING

Countries

United States

Central Contacts

Kristin Cadenhead

Role: CONTACT

KCADENHEAD@UCSD.EDU

619-543-6445

Facility Contacts

Kristin Cadenhead, MD

Role: primary

kcadenhead@health.ucsd.edu

619-543-6445

Heline Mirzakhanian, PhD

Role: backup

hmirzakhanian@health.ucsd.edu

619-543-7745

Tracy Alderman, PhD

Role: primary

talderman@ucsd.edu

619 543-7761

References

Dixon T, Cadenhead KS. Cannabidiol versus placebo as adjunctive treatment in early psychosis: study protocol for randomized controlled trial. Trials. 2023 Nov 30;24(1):775. doi: 10.1186/s13063-023-07789-w.

Reference Type: DERIVED

PMID: 38037108 (View on PubMed)

Other Identifiers

Cadenhead

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

649467 CMCR Grants Program

Identifier Type: -

Identifier Source: org_study_id