In a group of young people at high risk of psychosis, a single dose of the cannabis extract cannabidiol (CBD) reduced brain function abnormalities in regions implicated in psychosis, according to a study published online in JAMA Psychiatry.
The double-blind trial included 33 people who were experiencing psychotic symptoms but were not yet diagnosed with psychosis, along with 19 healthy control individuals. Among the participants at high risk of psychosis, 16 were randomized to receive a single dose of oral CBD and 17 to placebo. Participants who served as control subjects did not receive any drug.
All participants then performed a memory task that engaged 3 brain regions with known involvement in psychosis while undergoing magnetic resonance imaging (MRI) scans.
Compared with healthy participants, participants at high risk of psychosis demonstrated abnormal brain activity in the striatum, medial temporal cortex, and midbrain. However, among those who had received CBD, those abnormalities were less severe compared with their peers who received placebo. This suggests, researchers said, that CBD helps readjust brain activity to normal levels.
“The mainstay of current treatment for people with psychosis are drugs that were first discovered in the 1950s and unfortunately do not work for everyone,” said researcher Sagnik Bhattacharyya, MD, PhD, from the Institute of Psychiatry, Psychology & Neuroscience at King’s College London in England. “Our results have started unravelling the brain mechanisms of a new drug that works in a completely different way to traditional antipsychotics.”
CBD is a nonintoxicating compound found in cannabis that appears to work in opposition to tetrahydrocannabinol (THC), the ingredient responsible for inducing a high in users and which has been linked with psychosis development. Dr. Bhattacharyya and colleagues are currently launching a larger, multicenter trial investigating CBD treatment in people at high risk of psychosis.
“One of the main advantages of cannabidiol is that it is safe and seems to be very well tolerated, making it in some ways an ideal treatment,” said Dr. Bhattacharyya. “If successful, this trial will provide definitive proof of cannabidiol’s role as an antipsychotic treatment and pave the way for use in the clinic.”
Bhattacharyya S, Wilson R, Appiah-Kusi E, et al. Effect of cannabidiol on medial temporal, midbrain, and striatal dysfunction in people at clinical high risk of psychosis: a randomized clinical trial. JAMA Psychiatry. 2018 August 29;[Epub ahead of print].