The endogenous cannabinoid system has recently been shown of particular importance in the pathophysiology of acute schizophrenia. It interacts with various neurotransmitter systems in the central nervous system including the dopaminergic, glutamatergic and GABAergic system. While the psychedelic properties of the natural cannabis compound delta-9-tetrahydrocannabinol are widely known, there is some experimental and clinical evidence that other herbal cannabinoid compounds may have antipsychotic properties.
Based on these confounders we designed a four week, double-blind, controlled clinical trial on the effects of purified cannabidiol, a major compound of herbal cannabis, in acute schizophrenia and schizophreniform psychosis compared to the antipsychotic amisulpride. The antipsychotic properties of both drugs were the primary target of the study. Furthermore, side-effects and anxiolytic capabilities of both treatment strategies were investigated.
Cannabidiol significantly reduced psychopathological symptoms of acute psychosis after both, week two and four, when compared to the initial status. There was no statistical difference of this effect to the control condition. In contrast, Cannabidiol revealed significantly less side effects when compared to amisulpride.
This phase II clinical trial on the effects of Cannabidiol in acute schizophrenia and schizophreniform psychosis raises evidence for its antipsychotic properties that exceeds by far the evidence from open observations available up to now. Furthermore, it raises evidence that the endogenous cannabinoid system may provide a valid target in the search for new treatments for schizophrenia.
Acknowledgements: Funded by the Stanley Medical Research Institute (00-093 to FML) and the Koeln Fortune Program (107/2000 + 101/2001 to FML).
