Epilepsy is a neurological disorder characterized by abnormal electrochemical signaling usually accompanied by convulsions or seizures. There are many causes of epilepsy, varying based on the nature of the seizures as well as the age of onset. In 50% of cases, the cause is not known. Presently we know that structural abnormalities in the developing brain, infections like meningitis or encephalitis, or minimal to no oxygen to the brain during birth or after a stroke, can cause epilepsy. Brain injuries, particularly those that result in scar tissue, are also known to make one more susceptible to developing epilepsy. Oftentimes there is a considerable lapse in time between the brain injury and the onset of seizures. Epilepsy can also occur as a result of a tumour. People over 65 may develop epilepsy from degenerative conditions. In many cases involving very young children, genetics have been implicated. Genetics, however, can be a factor in developing epilepsy at any age. Some people are simply more prone to developing seizures than others. When there is a history of seizures in the family, there is a greater risk for an individual to develop epilepsy.
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Medical Cannabis Treatment of Epilepsy
There is a wealth of anecdotal evidence to suggest cannabinoids, particularly cannabidiol, may be able to reduce the severity and frequency of some forms of epilepsy. Recent studies have been conducted to assess the safety and efficacy of cannabidiol (CBD) in the treatment of refractory conditions such as Dravet and Lennox-Gastaut syndrome with very promising results.
While the exact mechanism by which cannabinoids exert their anticonvulsive effect is still not fully understood, researchers have identified synaptic control, the anti-inflammatory properties and the mediation of cell death as possible pharmacological targets.
The brain controls approximately 100 billion neurons that communicate with each other using electrical signals (known as action potentials) firing in the order of 70 times per second. During an epileptic event, such as a seizure, there is a ‘short-circuit’ in the electrical network of the brain causing rapid and unordered firing with up to 700 signals per second. Cannabidiol is thought to mediate over excitement through modulation of intracellular calcium, an ion heavily involved in neural signalling.
Increasing evidence is emerging to suggest inflammation is involved in both the development and long-term consequences of epilepsy. Research suggests brain tissues from individuals with refractory focal epilepsy resemble a chronic inflammatory state with elevated levels of inflammatory mediators. Cannabidiol is known to reduce the release of inflammatory compounds such as TNFα, a property that is thought to ameliorate neural inflammation.
Costa, B., Trovato, A. E., Comelli, F., Giagnoni, G., & Colleoni, M. (2007). The non-psychoactive cannabis constituent cannabidiol is an orally effective therapeutic agent in rat chronic inflammatory and neuropathic pain. European journal of pharmacology, 556(1), 75-83.
Cunha, J. M., Carlini, E. A., Pereira, A. E., Ramos, O. L., Pimentel, C., Gagliardi, R., … & Mechoulam, R. (1980). Chronic administration of cannabidiol to healthy volunteers and epileptic patients. Pharmacology, 21(3), 175-185.
Devinsky, O., Cilio, M. R., Cross, H., Fernandez‐Ruiz, J., French, J., Hill, C., … & Friedman, D. (2014). Cannabidiol: Pharmacology and potential therapeutic role in epilepsy and other neuropsychiatric disorders. Epilepsia, 55(6), 791-802.
Szaflarski, J. P., & Bebin, E. M. (2014). Cannabis, cannabidiol, and epilepsy—From receptors to clinical response. Epilepsy & Behavior, 41, 277-282.
Walker, L., & Sills, G. J. (2012). Inflammation and Epilepsy: The Foundations for a New Therapeutic Approach in Epilepsy? Epilepsy Currents, 12(1), 8–12. doi:10.5698/1535-7511-12.1.8