it's my understanding that yes they do damage the brain
I recall from somewhere that any brain damage is technically a "seizure" because the brain works like a long long long chemical "zipper" from A (birth) to Z (death) and that a seizure is sort of like causing another "zipper" to form off of the original zipper. Such that, in a psychotic seizure (which I think I've had) the zipper offshoot remains open for as long as it remains active, which can impair the person for a long time, in having a thought-duality, of sorts, that ideally resolves.
And that usually the zipper offshoot resolves rather quickly, and takes the person's consciousness with it (tonic-clonic unconscious, or lapses of consciousness as in a partial seizure), but that the zipper causes more and more zippers.
But instead of a jacket-zipper type, the zipper is a chemical zipper, which in being in a contrary state to the normal brain function, damages the routing of the brain chemistry. And if anything can be considered damaging to the brain it is by a chemical method. Absolutely seizures cause brain damage. A seizure is the same as a concussion to the brain.
Since the brain is consciousness, it IS life, it IS cognition, they definitely cause impairments. Which areas of the brain are affected and how deep the seizure goes can cause dramatic differences in the damage's effect to "normal day activities", but they all cause impairments.