Epilepsy is a chronic noncommunicable disease of the brain that affects around 50 million people worldwide. It is characterized by recurrent seizures, which are brief episodes of involuntary movement that may involve a part of the body (partial) or the entire body (generalized) and are sometimes accompanied by loss of consciousness and control of bowel or bladder function. Seizure episodes are a result of excessive electrical discharges in a group of brain cells. Different parts of the brain can be the site of such discharges. Seizures can vary from the briefest lapses of attention or muscle jerks to severe and prolonged convulsions. Seizures can also vary in frequency, from less than 1 per year to several per day."

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Although many underlying disease mechanisms can lead to epilepsy, the cause of the disease is still unknown in about 50% of cases globally."

Source : World Health Organization

Note: Many of the drugs which are currently used to treat epilepsy have unknown 'mechanisms of action'. e.g. Levetiracetamplugin-autotooltip__plain plugin-autotooltip_bigLevetiracetam

Levetiracetam, sold under brand names of Keppra, Elepsia, Epictal, Lenerve, Levepsy, Torleva (and many others) is a prescription-only anticonvulsant medication forepilepsy. It is used for partial onset, myoclonic, or tonic-clonic seizures. It is taken by mouth as an immediate or extended release formulation. There are currently more than 6 million prescriptions per year in the US alone., Valproateplugin-autotooltip__plain plugin-autotooltip_bigValproate

"Valproate (VPA) and its valproic acid, sodium valproate, and valproate semisodium forms are medications primarily used to treat epilepsy and bipolar disorder and prevent migraine headaches. They are useful for the prevention of seizures in those with absence seizures, partial seizures, and generalized seizures. They can be given intravenously or by mouth, and the tablet forms exist in both long- and short-acting formulations., Lamotrigineplugin-autotooltip__plain plugin-autotooltip_bigLamotrigine

Lamotrigine is used as an anticonvulsant and mood stabilizer. Currently prescribed in cases of epilepsy, Lennox–Gastaut syndrome and bipolar disorder. Its active biochemical pathways are not known. more info at Wikipedia

"The action mechanisms underlying the mood-stabilizing effects of lamotrigine are unknown at present but recent studies have produced interesting leads. Lamotrigine modulates various ion channels, altering neuronal excitability. The use-dependent inhibition of neu…, Gabapentinplugin-autotooltip__plain plugin-autotooltip_bigGabapentin

Gabapentin, a medicinal drug sold under the brandnames Gralise, Gabarone, Fanatrex, Neurontin (and many others) was discovered in the 1970s, and was first used as a muscle relaxant and painkiller.

In the US alone, it currently has more than 40 million prescriptions per year., Cannabidiol (CBD)plugin-autotooltip__plain plugin-autotooltip_bigCannabidiol (CBD)

Cannabidiol is an extract of the Cannabis plant which was licenced in the US in 2018 for use as a treatment for various types of Epilepsy

It's also used to treat Restless leg syndrome and some other movement disorders.

Despite intensive research efforts (it was first isolated in 1940) its 'mechanism of action' in successfully treating a range of neurological disorders is currently unknown. etc.

Also see : Psychogenic Non-Epileptic seizure (PNES)plugin-autotooltip__plain plugin-autotooltip_bigPsychogenic Non-Epileptic seizure (PNES)

Psychogenic non-epileptic seizures are seizure events which appear similar to those of Epilepsy, but without the associated (easily identifiable) electrical brainwave patterns.

The seizures can be severe, and last up to two minutes.