“This study is essentially showing how CBD might work, and which effects might underlie symptoms of psychosis,” he says. “But we seldom treat psychosis giving single doses; we have to give doses for various weeks before seeing clinical, meaningful results.”
The study was published Wednesday in Psychological Medicine.
Scientists compared brain scan results of people with a diagnosis of psychosis and people without the disorder as they were doing a memory exercise. In the people with psychosis, the researchers found clear differences in the activity patterns in their prefrontal, mediotemporal, and striatal areas of the brain — those that regulate decision making, learning and memory. But when these participants were given a single dose of CBD, their brain activity patterns were more similar to those of people without the disorder.
The results build on a 2018 study from the same team suggesting that CBD can normalize brain activity in people with symptoms of psychosis. This new study takes the work forward by including people with a clear diagnosis.
CBD and brain activity
The study included a group of 13 people with a diagnosis of psychosis and 16 people without the disorder. The participants were asked to perform three different verbal-association memory tasks (such as deciding whether words were paired in a logical way, and recalling which words they’d previously seen paired, or what font they were in) while in an fMRI machine.
“Now not only do we know that CBD works as an antipsychotic, we know it targets the areas of the brain that need to be targeted. This really gives us confidence, and it gives us scientific justification for large scale clinical trials," lead researcher on the study Sagnik Bhattacharyya tells Inverse.
Ultimately, the study sample is too small to draw definite conclusions on CBD as a treatment for psychosis patients as a group. The study also doesn’t look at how brain activity changes matched up to behavior in the participants with psychosis — which means we can’t know if CBD improved their performance on the memory tasks.
Can CBD treat psychosis?
The results provide insight into which part of the brain is affected by CBD and suggest CBD may curb symptoms of psychosis in the human brain.
The single dose of CBD appeared to diminish the differences in activity in the brains with psychosis and those without. For example, during memory exercises like recalling something verbally, a brain affected by psychosis has abnormal activity such as greater connectivity in the front of the brain (prefrontal, mediotemporal and striatal areas), which makes it harder to recall things logically. But after taking even just a single dose of CBD activation in these areas tended to look similar to that of a person without the condition.
There is no scientific consensus concerning the best CBD oil for psychosis, as the research is still underway. However, there is some evidence that CBD might aid in the treatment of neurological conditions such as schizophrenia and Parkinson's disease.
Is CBD an antipsychotic?
However, there is insufficient evidence to prove that CBD could affect brain function in people with schizophrenia. Research does not suggest or support use of medical cannabis as a treatment for such people.
Can CBD oil replace antipsychotics?
If such treatment is approved, though, it is also worth noting that CBD could have an antipsychotic effect, since it mimics the impact of these medications. In an animal trial, it was seen that CBD reduced hyperlocomotion, which stems in some cases from the stimulation of ketamine and amphetamine in people with schizophrenia.
According to the literature there is no need to titrate the dose of CBD. For risperidone, dose will start at 2 mg and after four days be increased to 2 mg BID. In clinical practice, risperidone is usually titrated within 2–7 days to 4 mg which is a dose that most subjects can tolerate with few adverse effects. To make the groups comparable, the dose of CBD will start at 300 mg once daily and after four days be increased to 300 mg BID. Participants can ingest the total dose once daily if they so prefer. If participants experience intolerable side effects after increasing the dose to two times daily after the first four days, it will be possible to reduce the dose to once daily after discussion and agreement with the investigator.
Personal and Social Performance Scale (rating scale – level of psychosocial functioning)
Participants will be compensated for their travel expenses to participate in the present trial. No other economic compensation for study participation will be offered.
Treatment resistance as defined by treatment (ever) with clozapine