A Clinical Trial on the Antipsychotic Properties of Cannabidiol

Despite recent advances in the treatment of schizophrenia and schizophreniform disorders, there is still a need to develop efficient and better tolerated psychopharmacological approaches to this group of diseases. The endogenous cannabinoid system provides a promising target in the pharmacotherapy of these disorders. This approach is based upon recent findings indicating that the human endogenous cannabinoid system is significantly involved in the pathogenesis of schizophrenia and that cannabidiol is effective in treating acute psychotic symptoms of schizophrenic patients. We will investigate cannabidiol versus placebo in a randomized, double blind design with extensive safety measures.

The primary hypothesis to be tested is that Cannabidiol is expected to be superior to placebo in the treatment of acute schizophrenic and schizophreniform psychoses with regard to its antipsychotic efficacy.

Inclusion criteria

• DSM-IV Diagnosis of schizophrenic or schizophreniform psychosis
• Minimal initial score of 36 in the BPRS total score and a minimum of 12 in the BPRS Psychosis Cluster, including items 4 (conceptional disorganisation), 8 (exaggerated self-esteem), 12 (hallucinatory behaviour), and 15 (unusual thought content)
• Exclusion of pregnancy in female subjects through negative β-HCG test

Exclusion criteria

• Lack of accountability
• Pregnancy or risk of pregnancy or lactation.
• Other relevant interferences of axis 1 according to diagnostic evaluation through MINI including undifferentiated residual forms of schizophrenia.
• Treatment with depot-antipsychotics during the last three months.
• Severe internal or neurological illness, especially cardiovascular, renal, advanced respiratory, haematological or endocrinological failures. Positive Hepatitis-serology.
• QTc-elongation.
• Acute suicidal tendency of or hazard to others by the patient