Stratification and Treatment in Early Psychosis Study -ASSIST

Summary

The purpose of this trial is:

* To investigate whether the response to clozapine treatment can be enhanced by adding cannabidiol (CBD), compared to placebo, in treatment resistant psychosis patients.
* To confirm the safety of CBD in people with psychosis.

The trial is a randomised, double-blind, placebo-controlled, multi-centre, international, clinical trial. Individuals with a diagnosis of treatment resistant psychosis in their illness who have had a suboptimal or no response to clozapine treatment will be recruited. These patients are randomised to treatment with oral CBD 500mg twice daily, or a matching placebo for 12 weeks, in addition to clozapine, which is standard care treatment for this population. By using a battery of clinical outcome assessments, the trial will assess several optional biomarkers 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 additional blood samples, stool samples, and complete neuroimaging assessments.

Conditions

• Treatment Resistant Psychosis
• Psychosis

Interventions

DRUG

CBD 100 mg/mL Oral Solution

Daily dose 1000mg, taken as 500mg (5ml) b.i.d for 6 weeks. For participants with a weight lower than 50 kg, the dose is to be adjusted to 20 mg/kg/day divided over 2 intakes of 10 mg/kg/day, for a period of 12 weeks

DRUG

Placeb

5ml b.i.d for 6 weeks; For participants with a weight lower than 50 kg, the dose is to be adjusted to 20 mg/kg/day divided over 2 intakes of 10 mg/kg/day, for a period of 12 weeks

Sponsors & Collaborators

• Wellcome Trust

  collaborator OTHER

• Cambridge Cognition Ltd

  collaborator INDUSTRY

• Cambridgeshire and Peterborough NHS Foundation Trust

  collaborator OTHER

• Oxford Health NHS Foundation Trust

  collaborator OTHER_GOV

• West London NHS Trust

  collaborator OTHER

• Charite University, Berlin, Germany

  collaborator OTHER

• University of Cologne

  collaborator OTHER

• Ludwig Maximilian university of Munich

  collaborator UNKNOWN

• University Hospital Frankfurt, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy

  collaborator UNKNOWN

• The Sheba Fund for Health Services and Research

  collaborator UNKNOWN

• Shalvata Mental Health Center

  collaborator OTHER

• Geha Mental Health Center

  collaborator OTHER

• Amsterdam University Medical Center

  collaborator OTHER

• National and Kapodistrian University of Athens

  collaborator OTHER

• Hospital General Universitario Gregorio Marañon

  collaborator OTHER

• Hospitales Universitarios Virgen del Rocío

  collaborator OTHER

• University of Campania Luigi Vanvitelli

  collaborator OTHER

• Psychiatric University Hospital, Zurich

  collaborator OTHER

• Douglas Hospital Research Centre

  collaborator UNKNOWN

• University of Oxford

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

QUADRUPLE

Model

PARALLEL

Eligibility

Min Age

16 Years

Max Age

50 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-06-30

Primary Completion

2028-09-30

Completion

2029-09-30

Countries

• Germany
• Greece
• Israel
• Italy
• Netherlands
• Spain
• Switzerland
• United Kingdom

Study Locations