CBD Oil Cognitive Function and Dementia
On this page we look at some of the research indicating the benefits of CBD oil for cognitive function, in particular looking at how it may be able to help patients with Alzheimer's, other forms of dementia and parkinson's disease
CBD and Alzheimer's
Laboratory studies have shown some potential for benefit from CBD/THC/Cannabis for the treatment
of Alzheimer’s disease (AD)
A key trait of Alzheimer’s disease is the build up of clumps of a protein, called amyloid, in the brain.
Some studies have shown that components of cannabis, including THC, appear to remove this protein from nerve cells grown in the lab.
THC is not present in over-the-counter CBD oil.
Another study that gave both THC and CBD oil to mice with symptoms of Alzheimer's
disease showed improvements in learning and had less evidence of amyloid clumps in their bodies.
Research continues to better understand
the effects of CBD oil on the brain. Some early evidence suggests that CBD oil may reduce inflammation in the brain, although this
has yet to be proven in people.
A useful review of the potential benefits of CBD oil for Alzheimer’s disease from in vivo studies
was published by Watt and Karl in 2017 in Frontiers of Pharmacology. It concluded: “the studies reviewed in this mini review provide
“proof of principle” for the therapeutic benefits CBD and possibly CBD-THC combinations pose for AD therapy”
Tackling the symptoms
Research does suggest that high concentrations of CBD oil could be useful for managing some of the symptoms of dementia
such as agitation and anxiety.
A few small clinical trials have assessed the effects of cannabinoids (including THC and synthetic
cannabinoids, such as nabilone) on behavioural symptoms of dementia. However, trials and studies so far have generally been small
or low quality so it is too early for definitive conclusions.
For example one 2019 Geneva based pilot study by Broers et al using high
concentrations of THC/CBD concluded: “an oral cannabis extract was well tolerated and greatly improved behaviour problems, rigidity,
and daily care in severely demented patients”.
It is also important to note that the researchers in these studies have used high concentrations
of CBD oil that may not be available to buy. These studies have also been short term so we still don’t know what the long term effects
of using CBD oil might be.
A study is currently underway at King’s College London that will look at whether a mouth spray containing
cannabinoids could be used to reduce symptoms of agitation and aggression in a small group of people with Alzheimer’s disease.
of the small studies available was undertaken by the Canadian Agency for Drugs and Technologies in Health in 2019 It concluded: “overall,
limited evidence from the studies3,10 included in this report suggested that medical cannabis may be effective for treating neuropsychiatric
symptoms associated with dementia (i.e., agitation, disinhibition, irritability, aberrant motor behaviour, nocturnal behaviour disorders,
and aberrant vocalization and resting care). There was also limited evidence of improvement in rigidity and cognitive scores as assessed
by MMSE”. The report then goes on to explain the limitations of the data and the need for further research
Treating and preventing
The jury is still out on whether cannabis THC or
CBD oil could be used to treat dementia. A lack of strong research studies
mean that anecdotal reports have in some cases taken the place of hard evidence.
No studies or trials have looked into the effects
of cannabis or its components on the underlying causes of Alzheimer's disease in people.
Whilst the studies in the laboratory show
some promise, it will be necessary to understand the wider effects that these components have before it is fully known whether they
have any effect - positive or negative - on the development of Alzheimer's in people.
It is worth noting that many of these studies
have involved a particular component of cannabis in isolation. Even if one component is found to influence dementia risk, it does
not necessarily mean that taking cannabis would have the same effect.
There is also a large amount of variation in the levels
of THC and CBD oil in different strains of the plant so the effects could depend on the type of cannabis used.
Impacts on Cognition
There is some evidence that heavy, long-term use of cannabis can have a negative effect on our memory and thinking.
Heavy use of cannabis is also associated with psychosis in some users. A 2018 study by Solowij et al found that CBD oil provided
improvements in attentional control and beneficial changes in psychological symptoms for those regularly taking Cannabis for recreational
purposes. However, more research needs to be done to tease apart any potential benefits and drawbacks.
There has been a lot of media coverage on the subject of the treatment of young people with epilepsy. That coverage has focused on medicines including THC. Here we look at CBD oil which does not include THC.
Several randomised control studies have demonstrated the efficacy
of CBD oil (with an acceptable safety profile) in patients with Lennox–Gastaut or Dravet syndrome causing epileptic seizures. A 2020
study by Royston et al looked at the processes by which CBD oil can provide “functional modulation of neuronal excitability”.
for Treating Parkinson’s Disease
A 2020 in vitro study by Gugliandolo et al presented results that indicated “that CBD may exert preventive
and protective actions in Parkinson’s Disease”. While an exploratory double blind human study indicated the results “point to a possible
effect of CBD in improving quality of life measures in PD patients with no psychiatric comorbidities; however, studies with larger
samples and specific objectives are required before definitive conclusions can be drawn.”
Our thanks to the UK Alzheimer’s Society for
help with content on this page