Epilepsy is a neurological condition affecting roughly one in one hundred people. Depending on the area of focus within the brain, there are a range of seizures that epileptic patients suffer, from brief - almost unnoticeable - lapses in consciousness known as "absence" seizures to full body convulsions known as "grand mal" seizures, with many stages in between. Most seizures are heralded by an "aura" of altered behavior and sensitivity to light and sound, and seizures can occur without obvious cause, or be triggered by stress, sleep deficiency, low blood sugar, certain kinds of strobe lights, or even boredom. Some of the common causes of epilepsy include birth injury, viral attacks, head traumas and hormonal imbalances, but it can also be idiopathic - which means there is no known cause.
Some kinds of epilepsy can be controlled with the use of anticonvulsant drugs, but there are also variants which don't respond well to drug therapy. When anticonvulsants are used, there are potentially dangerous side effects including emotional disorders, swollen gums, a decreased production of red blood cells, and softening of the bones. In addition, rarer side effects include loss of motor control, coma, and even death. In addition to side effects, anticonvulsants only completely stop seizures in about 60% of patients.
Cannabis has been known to have anticonvulsant properties for over a century, and studies were done on the use of marijuana to alleviate seizures as early as the 19th century. While most data available today is anecdotal, those personal stories do point to cannabis as an asset in the fight to control seizures. Cannabis analogues have shown to prevent seizures when prescribed in combination with more traditional medications, and patients who have been through the combined drug therapy have stated they are able to wean themselves off the conventional medication and still not have seizures as long as they have a regular supply of cannabis.
More recently, there has been some scientific interest in the use of cannabidiol, a cannabinoid drug, in epilepsy treatment. There is only a very little bit of data about this, but it shows that cannabidiol has almost none of the psychoactive side effects that whole cannabis (or its component element THC) tend to induce.
Nevertheless, there is no formal push to study the benefits of cannabis in epilepsy treatment, though the British Medical Association has stated that it could prove useful as an adjunctive therapy for patients who cannot be kept seizure free using only conventional drug therapy. The National Institutes of Health have echoed this sentiment, calling it an "area of potential value," though that decision is based largely on animal research.