The Use of Medical Marijuana For The Treatment of Epilepsy
In countries where medical use of marijuana is legal, a number of people with epilepsy report beneficial effects from using marijuana, including a decrease in seizure activity. Those who promote the medical use of marijuana often include treatment of epilepsy in the long list of disorders for which marijuana is supposed to be helpful. In fact, multiple states now have laws allowing the prescription of marijuana for the treatment of epilepsy.
There is, however, very little scientific literature to back up these claims. There is a single, small, randomized controlled clinical trial that demonstrates the effectiveness of marijuana use for the treatment for epilepsy in humans (Cunha, et al., 1980). (Randomized controlled clinical trials are the comparison tests where some people take the active medication and some people take an inactive placebo without knowing which pill they are taking. This type of experiment is required for all new FDA- approved medications.) There is some scientific evidence from animal studies regarding the effectiveness of marijuana (or the active ingredient in marijuana, most notably Δ 9-THC or tetrahydrocannabinol) for the management of epilepsy. Some animal studies suggest that THC can control seizures not responsive to other treatments. It is important to know that not all animal studies reflect what actually occurs in humans. Other studies show that THC can actually trigger seizures in addition to other adverse psychoactive effects (including depression and psychosis that can also occur with the use of marijuana.) Also, the withdrawal effects of marijuana on seizure activity have not been well studied. A person could be at a higher risk for seizures as marijuana is metabolized or if someone stops using marijuana all together. In addition, the effect that marijuana has on antiepileptic medication blood levels is largely unknown. Many legal and illegal ingested substances can alter levels of antiepileptic medications leading to increases seizures or toxic side effects. Use of marijuana can negatively affect memory (which is also a wellknown side effect of many antiepileptic drugs), that in turn can lead to missed medication doses and result in an increased risk of seizures. Finally, there is the potential for pulmonary (lung) complications from the inhalation of marijuana.
There is currently limited scientific data to support the use of marijuana in the treatment of epilepsy in humans. That said, there is a large volume of anecdotal evidence of its benefit and likely widespread use for treating epilepsy, as the laws of many states would imply. Studying the effects of marijuana on seizures in an appropriate and scientific environment is the optimal way to determine whether this currently illegal drug has any appropriate use in the treatment of epilepsy. The Epilepsy Foundation calls for further study of the role of THC in animal models and for randomized placebo controlled studies of this potential treatment of seizures.