Could a loss of 'natural cannabis' in the brain be the reason we get Alzheimer's disease?

Molecules called en docannabinoids are natural versions of psychoactive chemicals in cannabis

Disease symptoms are linked to losing beneficial effects of these molecules

When they are blocked, the signalling in the brain becomes inhibited

Causes the problems with memory and learning associated with dementia

But scientists warn simply smoking marijuana is not a solution



Alzheimer’s disease might partly develop because of the suppression of ‘natural cannabis’ molecules in the brain, scientists believe.



U.S. researchers linked early symptoms of the disease to losing the beneficial effects of these molecules, which are called endocannabinoids.

These signalling molecules are natural versions of psychoactive chemicals in cannabis.

Alzheimer's disease might develop because of the suppression of 'natural cannabis' molecules in the brain. Image shows a CT scan of a brain with the disease

A rogue protein called amyloid-beta, suspected of playing a key role in Alzheimer’s, is believed to block endocannabinoids in the brain in the earliest stages of the disease.



Endocannabinoids are part of the process that allows important signals in the brain to shine through while unwanted signals are shut out.

Blocking them results in the brain becoming too inhibited, leading to impaired learning and memory loss.



The scientists from Stanford University in California, who reported their findings in the journal Neuron, warned that simply smoking marijuana was not a solution to Alzheimer’s.



Senior author Dr Daniel Madison said: ‘Endocannabinoids in the brain are very transient and act only when important inputs come in.



Early symptoms of the disease are linked to losing the beneficial effects of these 'cannabis' molecules, which are called endocannabinoids

‘Exposure to marijuana over minutes or hours is different - more like enhancing everything indiscriminately, so you lose the filtering effect.



‘It’s like listening to five radio stations at once.’



Flooding the brain with external cannabinoids also ran the risk of inducing tolerance and impeding the ability of natural endocannabinoids to do their job, he said.