ME (chronic fatigue syndrome) Myalgic encephalopathy (ME) is a complex and controversial disorder characterized by chronic symptoms of fatigue that have no apparent cause and are not relived by rest. Although there is very little empirical research into the potential for cannabis to treat ME, countless sufferers report feeling subjective relief.
What is myalgic encephalopathy?
Myalgic encepalopathy (ME) has been known by various names in the decades since it was first described, including myalgic encephalomyelitis, chronic fatigue syndrome (CFS), chronic Epstein-Barr virus (due to the belief that the condition was caused by the Epstein-Barr virus), post-viral fatigue syndrome, and systemic exertion intolerance disease.
As well as feelings of intense, unrelenting physical and mental fatigue and postextertional (post-exercise) malaise, ME may also cause those affected to experience headaches, muscle and joint pain, sore throat, digestive disturbances, swollen lymph nodes, impaired memory and concentration, and depression. Symptoms vary in severity according to the individual, and in some cases can seriously detract from the patient’s quality of life.
Physiologically, ME is strongly associated with inflammation of the brain and spinal cord; this is reflected in the term “encephalomyelitis”, although this term is gradually being replaced by “encephalopathy” to reflect generalized dysfunction of the central nervous system. A 2014 study found that patients with ME/CFS exhibited markers of inflammation in certain brain regions that were 45-199% higher than in healthy controls.
What causes myalgic encephalopathy?
The underlying cause of ME is still unknown, and it is generally thought that a combination of genetic, environmental, infectious and psychological factors may be involved.
The possibility that viral infections play a role has not been discounted, although it appears that the previous belief that the Epstein-Barr virus (which is known to cause mononucleosis or glandular fever) was the underlying cause was in fact erroneous, as it is not present in all sufferers of the condition (now, the chronic fatigue experienced due to the virus is specifically termed Epstein-Barr chronic fatigue) . As well as this, chronic stress (lasting for six months or more) is believed to play a significant role.
Women make up the majority of ME cases, and there appears to be a slightly higher prevalence among Native Americans and African Americans than among white Americans; as well as this, family studies have demonstrated that blood relatives of sufferers are at increased risk of acquiring the disease, indicating that there is indeed a genetic element to its development.
Does cannabis use improve symptoms of ME?
Although there are apparently no empirical studies or clinical trials specifically investigating the ability of cannabis to ameliorate symptoms of ME, there are numerous existing patients in U.S. medical states who report experiencing subjective relief from symptoms.
Typically, patients report experiencing relief from disturbed or unrefreshing sleep, joint and muscle pain, depression, and emotional imbalance. Some patients also report that cannabis use actually improves the primary symptom of fatigue, with many of these reports stating that sativa-dominant strains are more effective than indica-dominant.
Again, while no specific studies into cannabis’ ability to improve the symptoms of ME, there are abundant studies investigating symptoms common in but not limited to the condition, such as disturbed sleep, chronic pain, energy regulation, immune function, and cognitive and emotional disturbances.
Which ME symptoms are most improved by cannabis?
The potential of cannabis to improve poor sleep is relatively well-established; various studies have demonstrated that while REM sleep is reduced, deep sleep is increased on cannabis, which may lead to overall greater levels of refreshment in the subject.
Chronic pain is also well-known to be improved with cannabis use, and it has been demonstrated that this is the case both for neuropathic (caused by an injury or dysfunction of the nerve itself) and nociceptive (caused by a factor other than injury to the nerve itself, such as a wound or inflammation in neighbouring tissue) pain.
The potential role of cannabinoids in the treatment of depression and cognitive impairment is controversial, but there are studies that imply that a positive effect could be gained by some patients, and that this positive effect is likely to depend on dose, regularity and history of use, and genetic and environmental factors.
Depression is thought to respond well to low doses and poorly to high doses of cannabinoid-receptor agonists such as THC, while memory has been shown to be improved with administration of rimonabant, a synthetic CB1-receptor antagonist that last year lost market approval as a weight-loss drug due to serious safety concerns.
Relationship between ME and fibromyalgia
There is such a high degree of comorbidity and so many shared symptoms between ME and fibromyalgia syndrome (FMS) that many believe it to be the same disease manifesting in slightly different ways between patients. 50-70% of patients diagnosed with FMS also fit the criteria for ME, and it is thought that the difference in diagnosis stems from physicians classing their patients’ symptoms either as disorders of the muscles and joints (FMS), or of the immune system and due to either external (e.g. viral) or autoimmune causes (ME/CFS).
FMS is a condition characterized by chronic pain in specific areas of the body, and heightened sensitivity to touch and pressure; sufferers also commonly experience chronic fatigue, muscle and joint pain, cognitive dysfunction, sleep disturbances, and depression. If the two conditions are one and the same, it could be said that FMS is the subtype in which pain is the primary symptom, and that fatigue is the primary symptom in the subtype currently known as ME or CFS.
While there has been a relative paucity of research specifically on ME and cannabis, there are a far greater number of studies into FMS and cannabis, many of which have found that cannabis can provide significant subjective relief of various symptoms, including muscle and joint pain, digestive dysfunction, and sleep disturbances.
The endocannabinoid system and ME
There have been a small number of studies investigating the role of the endocannabinoid system (ECS) in the development and progression of ME, and several studies investigating its role in stress and generalized fatigue, and post-viral fatigue conditions. As well as this, there are relatively abundant studies on the ECS and related conditions such as FMS, chronic stress, and multiple sclerosis (which also numbers chronic fatigue among its primary symptoms, and is in many ways similar to ME itself).
Essentially, it seems that the common thread underlying ME and chronic stress is inflammation within the brain and the tissues of the central and peripheral nervous system; furthermore, although inflammation is not generally thought to be a symptom of FMS, there is a growing body of evidence suggesting that the reverse may in fact be true, and that inflammation of the fasciae (the sheet of connective tissue that surrounds and encloses muscles and organs within the body) may have a central role to play. In multiple sclerosis, inflammation and destruction of the myelin sheaths surrounding the neurons of the brain and central nervous system is the underlying cause.
It has been firmly established that the ECS has a fundamental role to play in the occurrence and management of inflammation, and its involvement in FMS is also well-known. Furthermore, the fact that chronic stress is a major cause of inflammation in the central and peripheral nervous system is also now becoming well understood.
Research into inflammation, the immune system, and ME
An important 2012 study investigated the effect of exercise on gene expression in MS patients and ME patients compared with healthy controls. The study found that genes involved in the expression of metabolite-detecting and adrenergic receptors were increased in ME sufferers, while only certain adrenergic receptors were found to be increased in MS patients.
One adrenergic receptor found to be increased in ME patients was the TRPV1-receptor, which is not strictly part of the endocannabinoid system, although it has been demonstrated on various occasions that its biological mechanisms may be affected by ECS-related activity, and it is known that the endogenous cannabinoid anandamide is capable of activating it.
The relationship between anandamide, the TRPV-1 receptor and muscle fatigue deserves further investigation. Interestingly, a study conducted in 2010 investigated the potential benefits of regular consumption of high-cocoa, polyphenol-rich chocolate for individuals suffering from CFS, and found that symptoms were improved across the board for the high-cocoa group compared to controls. Cocoa-rich chocolate is known to contain compounds that are almost identical to anandamide, and it is thought that their mechanism of action (in supplying subjective feelings of well-being and relaxation) is effected via the TRPV-1 receptor.
Clearly, there is a great deal of work still to be done before our understanding of the relationship between the endocannabinoid system and conditions such as ME is complete. However, it is certain that the role of the ECS is fundamental to such conditions.