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Evaluation of the Antipsychotic Efficacy of Cannabidiol in Acute Schizophrenic Psychosis (CBD-CT1)

This study has been completed.
Information provided by:
University of Cologne Identifier:
First received: February 26, 2008
Last updated: March 17, 2008
Last verified: January 2008

A controlled, randomized study on the treatment of schizophrenic psychosis with cannabidiol, a phytocannabinoid is performed. This approach is based upon recent findings indicating that the human endogenous cannabinoid system is significantly involved in the pathogenesis of schizophrenia. Our group has shown, for example, that Δ9-tetrahydrocannabinol (Δ9-THC) is able to provoke schizophrenia-like psychotic symptoms in healthy volunteers. This, as well as the capability of Δ9-THC to exacerbate productive psychotic symptoms in schizophrenic patients, has recently been confirmed by others. Furthermore, we found that the en-dogenous brain constituent anandamide, an endogenous Δ9-THC agonist, is significantly elevated in the CSF of schizophrenic patients. Cannabinergic substances such as anandamide may enhance dopaminergic neurotrans-mission by increasing dopamine turnover. They may also influence the onset or course of schizophrenia by as yet unidentified mechanisms We seek to investigate the efficacy of cannabidiol in the treatment of schizophrenic and schizophreniform psy-choses, because there is evidence that CB1 antagonists such as SR141716 and cannabidiol have antipsychotic effects comparable to those of classic neuroleptic drugs. Furthermore, cannabidiol is well tolerated showing few side effects in humans. Cannabidiol may serve as an antipsychotic medication that is not primarily based upon an antidopaminergic but upon different mechanisms, especially anticannabinergic ones. It may therefore be an effec-tive medication in at least a subgroup of schizophrenic and schizophreniform patients and may be expected to show additional anxiolytic effects and only minor side effects.

The control condition in this parallel design will be an established neuroleptic treatment with amisulpride that is primarely an antidopaminergic drug. Thus, we will study not only the antipsychotic efficacy of cannabidiol, but we will also compare the effects of both treatment strategies on side effects and neuropsychological functioning.

Condition Intervention Phase
Drug: Cannabidiol
Drug: Amisulpride
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Evaluation of the Antipsychotic Efficacy of the Phytocannabinoid Cannabidiol in Treating Acute Schizophrenic Psychosis. A Double-Blind, Controlled Clinical Trial

Resource links provided by NLM:

Further study details as provided by University of Cologne:

Primary Outcome Measures:
  • Change in BPRS total value. [ Time Frame: 4 weeks ]

Secondary Outcome Measures:
  • Change in PANSS scores. [ Time Frame: 4 weeks ]
  • EPS [ Time Frame: 4 weeks ]
  • Weight gain [ Time Frame: 4 weeks ]
  • Prolactin levels in serum [ Time Frame: 4 weeks ]

Estimated Enrollment: 42
Study Start Date: October 2002
Study Completion Date: March 2008
Primary Completion Date: November 2004 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: 1 Drug: Cannabidiol
Capsules, 3 times daily, 200 mg, 4 weeks
Active Comparator: 2 Drug: Amisulpride
Capsules, 3 times daily, 200 mg, 4 weeks


Ages Eligible for Study:   18 Years to 65 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Clinical diagnosis of schizophrenia or schizophreniform psychosis according to DSM-IV.
  • BPRS score >36 and BPRS psychosis cluster > 12.
  • Ability to provide written informed consent.
  • Participants are required an adequate contraception.

Exclusion Criteria:

  • Any severe neurological or somatic disorder.
  • Other psychiatric disorders including addictive disorders.
  • Positive urine drug screening for any compound except benzodiazepines.
  • No pregnancy or breast feeding.
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Please refer to this study by its identifier: NCT00628290

University of Cologne, Dept. of Psychiatry and Psychotherapy
Cologne, NRW, Germany, 50924
Sponsors and Collaborators
University of Cologne
Principal Investigator: Franz-Markus Leweke, MD University of Cologne, Dept. of Psychiatry and Psychotherapy
  More Information

Additional Information:
Responsible Party: Dr. F. Markus Leweke, University of Cologne Identifier: NCT00628290     History of Changes
Other Study ID Numbers: CBD-CT1
SMRI Grant ID: 00-093
Study First Received: February 26, 2008
Last Updated: March 17, 2008

Additional relevant MeSH terms:
Schizophrenia Spectrum and Other Psychotic Disorders
Mental Disorders
Antipsychotic Agents
Tranquilizing Agents
Central Nervous System Depressants
Physiological Effects of Drugs
Psychotropic Drugs
Dopamine Antagonists
Dopamine Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action processed this record on April 27, 2017