It has been known for some time that THC may make psychosis worse in persons who are at risk for schizophrenia and other psychotic disorders. There have also been studies finding that CBD decreases the risk of psychosis in these people. The mechanism of this antipsychotic property has been elusive. A team of researchers from King’s College in London Performed an interesting double-blinded placebo study that was published last year in JAMA Psychiatry.
The authors studied 33 persons deemed “at clinical high risk” (CHR) for psychosis and compared them to 19 health control participants. 16 of the CHR subjects received a single 600mg dose of CBD and the remaining 17 received a placebo. Control participants did not receive anything. According to the researchers “All subjects were then studied using functional magnetic resonance imaging (fMRI) while performing a verbal learning task.”
This design allowed the researchers to see what is happening in the brain in real time while participants are using their brains to perform a standard task. They found that “Cannabidiol [CBD] may partially normalize alterations in parahippocampal, striatal, and midbrain functions associated with the CHR state.” They believe that these brain regions are involved in psychosis and that the CBD acted as a therapeutic agent to normalize brain function in these areas.
All subjects had been asked to avoid alcohol, cannabis, and other recreational drugs prior to the study and a urine test was performed to confirm that they complied with these instructions. They performed some fairly complex statistical analyses comparing the different groups – control participants, placebo participants, and CBD participants. In general the participants at high risk for psychosis showed brain patterns intermediate between the placebo participants and the controls. CBD apparently partially corrected the problems that were developing in their brains.
Will CBD ever be used as a treatment for psychosis? That’s not as far-fetched as it sounds. High dose CBD (in the form of Epidiolex) is already FDA approved to treat certain seizure disorders. It could certainly be studied as a treatment for psychosis as well.