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expert reaction to cannabinoid may improve learning and memory in old mice

Publishing in Nature Medicine researchers report low-dose administration of  the cannabinoid delta-9 tetrahydrocannabinol (THC) can improve age-related learning and memory deficits in mice.


Dr Michael Bloomfield, Clinical Lecturer in Psychiatry at University College London, said:

“This new, well-conducted study published in the respected journal Nature Medicine investigated the effects of low doses of one of the major active ingredient in cannabis, delta-9 tetrahydrocannabinol (THC), on memory function and brain cells in mice.

“It’s been known for some time that regular high doses of THC during adolescence, a period when our brains are still developing, is potentially harmful for memory function. This new study investigates this in old mice showing signs of age-related worsening of memory function. The researchers found that low doses of THC appeared to improve both memory function and markers of brain cell function in old mice. What is particularly exciting about this research is that it opens up a whole new chemical system, called the endocannabinoid system, as a potential target for new avenues of research which could include illnesses like dementia. However, we are still in very early days and further research is needed. This is because THC produces very complicated and sometimes seemingly opposite effects depending on, for example, its dose, age of the person or animal, how often the drug is administered and species differences in all of the above. This means that the possibility of doctors potentially prescribing, cannabis THC or similar compounds for memory problems in older people is still a long way off.”


Prof. David Nutt, The Edmond J Safra Chair and Head of the Centre for Neuropsychopharmacology, Imperial College London, said:

“This is a robust study of aging in mice that uses well-established techniques to explore memory function and the underpinning neurochemical mechanisms. The results do not surprise me as there are many pre-clinical studies showing neuroprotective effects of cannabinoids.  The key question is now does the same apply to humans?  Clearly this needs to be tested but this will not be possible in the UK due to the ridiculous restrictions on cannabis research occasioned by its being a Schedule 1 drug.  However I think cannabis might be neuroprotective in humans as our own research has shown that alcoholics who use cannabis have less alcohol-induced brain damage than those that don’t.”


* ‘A chronic low dose of ∆9-tetrahydrocannabinol (THC) restores cognitive function in old mice’ by Bilkei-Gorzo et al. will be published in Nature Medicine on Monday 8th May.


Declared interests

Dr Bloomfield: “I am a member of the Royal College of Psychiatrists, a member of the British Association of Psychopharmacology, a young member of the European College of Neuropsychopharmacology, a young fellow of the Royal Society of Medicine and an international member of the American Psychiatric Association. I conduct research funded by the Medical Research Council, the National Institute of Health Research and the British Medical Association. I work in medical research at the Medical Research Council and University College London. I work clinically in the National Health Service. I have no other interests to declare.”

Others: None declared

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