A new small study found that when patients diagnosed with psychosis took one dose of cannabidiol (CBD), their brain activity in certain regions started to resemble that of a non-psychosis brain.
CBD is one of more than 100 chemical compounds known as cannabinoids found in the cannabis plant. There has been recent interest in the use of CBD as an alternative to current antipsychotic medicines as it could prove to be more tolerable and more effective for a subset of people who do not respond to available antipsychotics.
Its use has been linked to a decrease in psychotic symptoms and changes in brain activity during verbal memory tasks in patients at high risk of psychosis.
The new study, published in the journal Psychological Medicine, used fMRI scans to examine the brain activity of 13 people with a diagnosis of psychosis under the influence of a single dose of CBD or placebo and 16 controls. All participants were engaging in a memory task during the scan.
The results reveal that, during the task, there was a different pattern of activity in the prefrontal and mediotemporal brain areas of people with psychosis taking placebo compared to the activity seen in those without psychosis.
But when the psychosis patients were given one dose of CBD, the activation in these brain areas became more like the activation seen in controls.
“Our study provides important insight into which areas of the brain CBD targets,” said senior author Professor Sagnik Bhattacharyya from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London.
“It is the first time research has scanned the brains of people with a diagnosis of psychosis who have taken CBD and, although the sample is small, the results are compelling in that they demonstrate that CBD influences those very areas of the brain that have been shown to have unusual activity in people with psychosis.”
The study also showed that activity in the striatum and in the hippocampus was more coordinated in people with psychosis, indicating there was a greater functional connectivity between these two areas in this group compared to controls.
After one dose of CBD this functional connectivity was reduced in people with psychosis and became more similar to that seen in the controls. The patients with psychosis continued on their existing antipsychotic treatment throughout the study.
The findings suggest that CBD has a moderating effect on the altered pattern of brain activity in the prefrontal, mediotemporal and striatal areas in people with psychosis.
The researchers also found that psychotic symptoms did show a decreasing trend after the dose of CBD but researchers highlighted that no definitive conclusions could be drawn about this effect as the study did not look at sustained use of CBD and the sample size was small.
“This study provides important insight into the brain mechanisms behind the antipsychotic effects of CBD,” said Bhattacharyya.
“It gives confidence in the antipsychotic potential of CBD by demonstrating that it targets the function of brain regions implicated in psychosis and indicating that even a single dose may ameliorate some of the brain function alterations that may underlie psychosis.”
Bhattacharyya added, “The finding that psychotic symptoms may show a trend towards improvement in this group even after one dose of CBD is encouraging, but requires a larger scale clinical trial to investigate if the effects would continue with longer term treatment.”
Source: King’s College London