Every year, on Sept. 21, we celebrate World Alzheimer's Day, a day dedicated to the achievements of medical research that could one day better the lives of millions of people affected by the disease.
Every 68 seconds, someone is diagnosed with Alzheimer's disease. Over 4.5 million Americans are estimated to be currently afflicted with the disease. Experts warn that at such rates, the number of Americans living with Alzheimer's will quadruple to as many as sixteen million patients by 2050.
Alzheimer's disease (AD) is a neurological disorder characterized by a progressive loss of memory and behavioral problems. It is the cause of up to 70 percent of dementia. The most common variety of the condition begins after the age of 65. Among risk factors, there are genes, a history of head injuries, hypertension, and depression.
At first, symptoms include only mild confusion and difficulty remembering. Patients often have difficulty making and storing new memories. As the condition advances, people may experience problems with language, depression, appetite loss, agitation, and behavioral issues. They are not able to do simple math and become delusional. Later, the brain loses the ability to handle basic bodily functions such as walking, speaking, and swallowing. Eventually, the patient dies.
So far, scientists do not know how to prevent Alzheimer’s. Furthermore, there is no approved treatment or medication available for this progressive, ultimately fatal condition, although a few pharmaceuticals have been approved by the FDA to temporarily alleviate or ease some of the symptoms. However, most of them are insufficient and have side effects.
In the recent years, medical marijuana studies have shed some light on a new solution in medicine: researchers found that cannabis compounds demonstrated outstanding results in the lab. Looking forward, scientists are pretty optimistic on the matter of the role of the endocannabinoid system in dealing with neurodegenerative diseases like Alzheimer's.
Currently, there are four drugs for the management of mild to moderate symptoms of the disease including donepezil, galantamine, tacrine, and rivastigmine. In fact, none of them can be considered a perfect fit. First of all, they do not work well for most people. Secondly, they also do not stop the progression of the disease but only delay it or temporarily help with symptoms control, particularly in the earlier stages. Thirdly, Alzheimer's medication can cause side effects, from relatively minor (dizziness, vomiting, and nausea) to debilitating (slower heartbeat, gastrointestinal bleeding, convulsions, and seizures). And, finally, they are extremely expensive: an average monthly prescription may range from $170 to $400.
Alzheimer’s is one of the diseases treated with medical cannabis.
Spanish researchers at the Cajal Institute and the Complutense University of Madrid took up a study on the localization, expression, and function of cannabinoid receptors in Alzheimer's disease and the possible protective role of cannabinoids after treatment. By 2005, the scientists found that activated cannabinoid receptors could block certain negative actions of microglia cells. Put simply, in a healthy brain, these cells play the role of removing cell debris and toxic substances and calm inflammation; but in people with Alzheimer's, they cease to function properly. The study showed that with activating cannabinoid receptors in a rat's brain, microglia cells could be restored to their regular function, and the destructive effect of the disease can be prevented. Follow up studies at the Hebrew University of Jerusalem also demonstrated that CBD might mitigate memory loss in mice, the first and primary symptom of Alzheimer's.
In 2006, The Scripps Research Institute in California reported that THC preserved brain levels of the key neurotransmitter acetylcholine. The experiment also showed that the THC molecule might impact the disease pathology by preventing the formation of the amyloid plaques that are a hallmark of Alzheimer's and its damage to the brain. According to the researchers, such compounds “may provide an improved therapeutic for Alzheimer's disease, augmenting acetylcholine levels by preventing neurotransmitter degradation and reeducating amyloid beta aggregation, thereby simultaneously treating both the symptoms and progression of Alzheimer's disease.” Preliminary lab studies at the Salk Institute showed similar results in 2016.
American scientists at Ohio State University, Department of Psychology and Neuroscience, tried to treat rats with synthetic cannabinoid receptor agonists in order to study the role of the endocannabinoid system in Alzheimer's. In a 2006 report published in Neuroscience, the researchers stated that the animals experienced a 50 percent improvement in memory and reduction in inflammation compared to controls. Certain following studies reiterated the importance of CB1 receptors in the antiinflammatory effect. Particularly, in 2009, Spanish researchers found that mice bred without CB1 receptors experienced faster cognitive degeneration.
Although the connection between the endocannabinoid system and neurodegenerative illnesses has not been studied in human trials, the results of preliminary trials are pretty promising.
Not only the psychoactive THC but also cannabidiol, known as CBD, has something to offer to Alzheimer's studies.
In 1998, Prof. A. J. Hampson and his colleagues reported that cannabinoids could prevent cell death by antioxidation. CBD was found to prevent glutamate neurotoxicity and ROS-induced cell death, and THC—to also block glutamate neurotoxicity with a similar potency to CBD. Other tested cannabinoids—cannabinol, levonantradol, and nabilone—also exhibited oxidation profiles similar to CBD and THC.
A 2004 report by Italian scientists noted CBD's antioxidative, antiapoptotic, and neuroprotective properties: cannabidiol significantly elevated cell survival while decreasing the production of reactive oxygen species (ROS), DNA fragmentation, and lipid peroxidation.
The synergistic potential of CBD and THC is truly impressive. It is a rare, if not unique, combo that can afford neuroprotection by utilizing its various properties that cover almost all spectra of neurotoxic mechanisms that operate in neurodegenerative disorders.
Persons with Alzheimer's are at high risk for weight loss, especially as the illness progresses. However, weight loss may occur in the pre-symptomatic phase of the disease and often leads to infections, anorexia, muscle atrophy, and accelerated loss of functional independence of patients.
Certain clinical trials indicate that cannabis therapy may stimulate weight gain and reduce agitation. A 2006 study by German researchers showed that the patients who used 2.5 mg of synthetic THC on a daily basis for two weeks experienced a reduction in nocturnal motor activity and agitation. Moreover, the drug did not show any side effects. Thus, the researchers might conclude that THC is a new safe treatment option for behavioral and circadian rhythm disturbances in Alzheimer's disease.