Source: Daily Mail
by Fiona Macrae
13 Jun 2010
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
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
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
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
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
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
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
‘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.’