Just a single dose of cannabidiol (CBD), the non-psychoactive compound of cannabis, temporarily increases blood flow to certain regions of the brain. This observation, the researchers say, could help to explain some of the much-hyped therapeutic effects of CBD for people with PTSD, anxiety, and other mental health problems.

Reported in the Journal of Psychopharmacology, scientists at University College London (UCL) gave 15 healthy young people 600mg of oral CBD or a placebo on different occasions. The researchers then used magnetic resonance imaging (MRI) scans to see how the drugs changed blood oxygen levels in their brains.

They found that a single dose of CBD significantly increased blood flow to the hippocampus, a brain structure that plays a role in emotions, learning, and memory. They also noted increased blood flow to the prefrontal cortex, an area in the orbitofrontal cortex that’s used to process social behavior and decision-making. 

“To our knowledge, this is the first study to find that CBD increases blood flow to key regions involved in memory processing, particularly the hippocampus,” Dr Michael Bloomfield, lead study author from UCL Psychiatry, said in a statement.

The past few years have seen CBD become the subject of a lot of hype among evangelists of health and wellbeing. It can be found in everything from food supplements and dog food to face creams and coffee. However, much of the evidence is anecdotal and not all of the lofty claims surrounding CBD have been put through the wringer of scientific study. 

With that said, a number of studies have shown that CBD may hold promising pharmaceutical properties. CBD is commonly used to address anxiety, and some studies have shown it can ease symptoms of epilepsy, depression, or chronic pain. There is also evidence to suggest CBD can improve memory, which is perhaps surprising when you consider the well-known effects of cannabis use on memory.  

According to the researchers, their findings appear to affirm some of these much-touted benefits of CBD. 

“Cannabidiol is one of the main constituents of cannabis and is gaining interest for its therapeutic potential. There is evidence that CBD may help reduce symptoms of psychosis and anxiety. There is some evidence to suggest that CBD may improve memory function,” explained Dr Bloomfield.

“Additionally, CBD changes how the brain processes emotional memories, which could help to explain its reputed therapeutic effects in PTSD and other psychiatric disorders. However, the precise mechanisms underlying the effects of CBD on memory are unclear.”