Researchers from University College London (UCL) have found a single dose of cannabidiol (CBD) can help increase blood flow to the hippocampus, an area of the brain associated with memory and emotion.

The findings could help with treatment options for conditions which affect memory such as Alzheimer’s disease and post-traumatic stress disorder (PTSD).

In the study, published in the Journal of Psychopharmacology, researchers investigated how CBD influences cerebral blood flow in different regions of the brain involved in memory processing.

During the randomised controlled study of 15 healthy young adults, with little or no history of cannabis use, each participant was given 600mg of oral CBD or a placebo on different occasions, seven days apart.

The doses came in identical capsules, so participants didn’t know which one they were taking on which occasion.

Researchers measured blood flow to the hippocampus using ‘arterial spin labelling’ – a MRI brain scan which measures changes in blood oxygen levels.

They found that CBD significantly increased blood flow in the hippocampus and the prefrontal cortex, the area of the brain used for planning and decision making.

Lead author Dr Michael Bloomfield from UCL Psychiatry said: “There is evidence that CBD may help reduce symptoms of psychosis and anxiety. There is some evidence to suggest it may improve memory function.

“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, UCL psychiatry

“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.”

Dr Bloomfield added: “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.

“This supports the view that CBD has region-specific blood flow effects in the human brain, which has previously been disputed.

“If replicated, these results could lead to further research across a range of conditions characterised by changes in how the brain processes memories, including Alzheimer’s disease, where there are defects in the control of blood control flow, along with schizophrenia and post-traumatic stress disorder.”

The researchers acknowledged the study used a single dose of CBD in healthy volunteers and the effect may not be replicated in repeated doses.

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