In 2011 an Australian group of researcher’s studied the effects of CBD for the treatment of Alzheimer’s in mice. The researchers — Tim Karl and Carl Group — explain that they were prompted to conduct the review because CBD has shown to possess neuroprotective, anti-inflammatory, and antioxidant properties in vitro.
Karl and Group discovered that CBD shows promise for therapeutic application for Alzheimer’s. Findings also indicate that CBD promotes neurogenesis, or the growth and development of neurons, to in turn reduce the deterioration of cognitive functions. In the preclinical animal studies, CBD has shown to reverse and prevent the development of cognitive deficits.
In one, three weeks of daily CBD treatments was effective at reversing the cognitive deficits of mice with injection-induced Alzheimer’s disease. Another found that eight months of CBD treatments helped prevent the development of social recognition memory deficits. Some studies also suggest that CBD’s therapeutic effects for Alzheimer’s disease are even greater when combined with tetrahydrocannabinol (THC), the well-known psychoactive compound.
An estimated 5.5 million Americans are living with Alzheimer’s, and as of now there is no cure. The disease takes more lives than breast cancer and prostate cancer combined. Karl and Group believe their review’s findings are encouraging and urge for clinical trials so that CBD’s potential benefits for Alzheimer’s disease can be tested for efficacy and safety on human subjects.
Presence of senile plaques in the brain is a hallmark of AD. These plaques are composed of extracellular deposits of beta-amyloid proteins derived from aberrant metabolism of transmembrane amyloid precursor protein. Aβ fragments are present across the brain regions and play a vital role in the pathogenesis of Alzheimer’s, memory loss, behavioral changes and neuronal cell death.
Senile plaques are usually covered by microglia (the brain’s immune cells) in an attempt to phagocytose the plaques and to clear the Aβ burden. When the plaque deposition exceeds the clearing ability of microglia, inflammatory cascades are activated by the immune cells. This inflammatory response actually promotes an increased respond of the progression of Alzheimer’s.
Autopsy studies have reported increased expression of CB1 and CB2 receptors on microglia in the senile plaques. The presence of CBD has the potential to activate cannabinoid receptors and mitigate these pathological events caused by Alzheimer’s. This evidence has pointed to the role of the endocannabinoid system in the mitigation of the neurodegenerative process, which can offer more effective options to treat AD.