Cannabis 'could stop dementia in its tracks'



Cannabis may help keep Alzheimer's disease at bay.



In experiments, a marijuana-based medicine triggered the formation of new brain cells and cut inflammation linked to dementia.



The researchers say that using the information to create a pill suitable for people could help prevent or delay the onset of Alzheimer's.

A medicine based on cannabis (right) could help to delay the onset of Alzheimer's

The incurable disease affects 400,000 Britons, with around 500 new cases diagnosed every day as people live longer.



For some sufferers, drugs can delay the progress of devastating symptoms such as memory loss and the erosion of ability to do everyday things such as washing.

However, there they do not work for everyone and, with the number of patients forecast to double in a generation, there is a desperate need for new treatments.



The US researchers studied the properties of a man-made drug based on THC, the chemical behind the 'high' of cannabis.



When elderly rats were given the drug for three weeks, it improved their memory, making it easier for them to find their way round a water maze, the Society for Neuroscience's annual conference heard yesterday (WEDS).



Researcher Dr Yannick Marchalant said; 'Old rats are not very good at that task. When we gave them the drug, it made them a little better at that task.'



Other experiments showed that the drug acts on parts of the brain involved in memory, appetite, pain and mood.



The Ohio State University experiments also showed that the drug cut inflammation in the brain and may trigger the production of new neurons or brain cells.



Researcher Professor Gary Wenk said: 'When we're young, we produce neurons and our memory works fine.



'When we age, the process slows down, so we have a decrease in new cell formation through normal ageing.



'You need these cells to come back and help form new memories and we found that this THC-like agent can influence the creation of these cells.'



Although the drug used was not suitable for use in people, the results could aid the creation of new medicines for Alzheimer's.



It is likely such a drug would be taken to prevent the disease, rather than treat it.



Asked if those with a family history of Alzheimer's should smoke cannabis to prevent them developing the disease, Dr Wenk said: 'We're not saying that but it might actually work.



'What we are saying its that it appears that a safe, legal substance that mimics the important properties of marijuana can work on the brain to prevent memory impairments in ageing. So that's really hopeful.'



Dr Marchalant added: 'We hope a compound can be found that can target both inflammation and neurogenesis, which would be the most efficient way to produce the best effects.'



The medicinal properties of cannabis have already been harnessed to treat multiple sclerosis.



Sativex, a cannabis-based drug, has been shown to ease the symptoms of multiple sclerosis, including pain, spasms, shaking, depression and anxiety.



The Alzheimer's Society cautioned against using cannabis itself to stave off dementia.



Professor Clive Ballard, the charity's director of research, said: 'There are encouraging findings from studies with animals suggesting that some cannabis derivatives may help protect nerve cells in the brain.



'We therefore look forward to robust clinical trials into potential benefits of non-psychoactive components of cannabis.



'It is important for people to note that these treatments are not same as recreational cannabis use which can be potentially harmful.'