Zuardi AW, Crippa JA, Hallak JE, Moreira FA, Guimarães FS.
A high dose of delta9-tetrahydrocannabinol, the main Cannabis sativa (cannabis) component, induces anxiety and psychotic-like symptoms in
healthy volunteers. These effects of delta9-tetrahydrocannabinol are
significantly reduced by cannabidiol (CBD), a cannabis constituent which
is devoid of the typical effects of the plant. This observation led us
to suspect that CBD could have anxiolytic and/or antipsychotic actions.
Studies in animal models and in healthy volunteers clearly suggest an
anxiolytic-like effect of CBD. The antipsychotic-like properties of CBD
have been investigated in animal models using behavioral and
neurochemical techniques which suggested that CBD has a pharmacological
profile similar to that of atypical antipsychotic drugs. The results of
two studies on healthy volunteers using perception of binocular depth
inversion and ketamine-induced psychotic symptoms supported the proposal
of the antipsychotic-like properties of CBD. In addition, open case
reports of schizophrenic patients treated with CBD and a preliminary
report of a controlled clinical trial comparing CBD with an atypical
antipsychotic drug have confirmed that this cannabinoid can be a safe
and well-tolerated alternative treatment for schizophrenia. Future
studies of CBD in other psychotic conditions such as bipolar disorder
and comparative studies of its antipsychotic effects with those produced
by clozapine in schizophrenic patients are clearly indicated.