Epilepsy and Marijuana

Epilepsy is a severe disorder of the Central Nervous System in which normal activity of the neurons are disrupted leading towards seizures or convulsions, bizarre sensations, muscle spasms and loss of consciousness. Symptoms of seizures vary from person to person. In some cases, convulsions present with a blank stare lasting only a few seconds to a number of minutes but in other cases patients twitch their legs or arm repeatedly. Seizures require immediate treatment because they can be life threatening or disabling. Surgery or immediate treatment even in case of mild seizures can control seizures in approximately 80% of individuals with epilepsy (Although this is normally only considered in very serious situations) [1, 2].

Prevalence of Epilepsy and Marijuana Use

The prevalence of epilepsy vary, but according to research the prevalence of seizure disorder is approximately 1 in 26 people in the U.S. It is present in approximately 1% of children and in 1.8% of adults having an age more than 18 and about 10 percent of these people have had a single unprovoked seizure. In 2013 the prevalence of epilepsy was 5.1 million in the U.S. [1, 3, 4]. 21% of patients that used cannabis in a trial are reporting beneficial effects [5].

Mechanism of Cannabis Action

Epilepsy is the disorder of central nervous system. The Endocannabinoid system regulates the stimulatory effect of neurons. Endocannabinoid CB1 receptors present in the brain and central nervous systems and to a lesser extent in other tissues that regulate the stimulation of neurons (Figure 1). Activation of the CB1 receptor stimulates the neurons that worsen the condition of epilepsy due to the stimulation of electrical conduction by the activation of excitatory synapses. Cannabinoids present in cannabis prevent the effect of the endocannabinoid system to decrease the psychoactive or stimulatory effects [6, 7].

epilepsy
Figure 1: Distribution of CB1 receptors (In central nerve system) and CB2 receptors (In peripheral tissues) and action of tetrahydrocannabinol (THC), Cannabidiol (CBD) and Cannabinol (CBN).

Cannabinoids Useful in Epilepsy

Tetrahydrocannabinol has psychoactive effects, but on the other hand cannabidiol (CBD) has antipsychotic effects. CBD is a non psychotropic compound of Cannabis sativa not only decreases the stimulatory effect of neurons, but has a neuroprotective role as well. The anticonvulsant effect of CBD related with G-protein-coupled receptor GPR55 and 5-HT1a receptor. CBD also affect the α3 and α1 glycine receptors that are neuroprotective in nature [8, 9].

Uses of Cannabis in Various Form of Epilepsy

CBD is useful in various forms of Epilepsy such [10]:

  1. Primary generalized epilepsy
  2. Treatment resistant epilepsy
  3. Acute epilepsy
  4. Recurrent seizures
  5. Tonic colonic seizures

References

  1. Clinic, M. Epilepsy. 2014 14 October 2015]; Available from: http://www.mayoclinic.org/diseases-conditions/epilepsy/home/ovc-20117206
  2. National Institute of Neurological Disorders & Stroke. Epilepsy. 2015 14 October 2015]; Available from: http://www.ninds.nih.gov/disorders/epilepsy/epilepsy.htm.
  3. Kobau, R., et al., Epilepsy in adults and access to care — United States. Morbidity and Mortality Weekly Report 2012. 61(45): p. 909-913.
  4. Russ, S.A., K. Larson, and N. Halfon, A national profile of childhood epilepsy and seizure disorder. Pediatrics, 2012. 129: p. 256-264.
  5. Gross, D.W., et al., Marijuana use and epilepsy: prevalence in patients of a tertiary care epilepsy center. Neurology, 2004. 62(11): p. 2095-2097.
  6. Cannabinoids And Epilepsy. Cannabis Resource And Research Network Available from: http://-article-26282273.cannabisresource.net/.
  7. Weeding Out Bad Waves: Towards Selective Cannabinoid Circuit Control In Epilepsy. Cannabis Resource And Research Network. Available from: http://-article-25891509.cannabisresource.net/index.php?cannabis=g.
  8. Devinsky, O., et al., Cannabidiol: Pharmacology And Potential Therapeutic Role In Epilepsy And Other Neuropsychiatric Disorders. Cannabis Resource And Research Network. Epilepsia, 2014. 55(6): p. 791-802.
  9. Cilio, M.R., E.A. Thiele, and O. Devinsky, The case for assessing cannabidiol in epilepsy. Epilepsia, 2014. **(*): p. 1-4.
  10. Urban Farmacy. Seizures & Cannabis. 2014 14 October 2015]; Available from: http://www.urbanfarmacyprc.com/seizures-cannabis/.