I also say cortisol, which would be related to stress, and I would add depression. Both affect memory in my opinion. I think memory failures can be protective actually. Vague memory of events can save us from PTSD later, or something retriggering us.
@RayaHope Have you asked your doctor about it? I don’t think periodic seizures usually cause brain damage. I think of brain damage from seizures in children who seize multiple times daily and it’s very severe. I really don’t have any medical knowledge about it though. The parents of those children know the risk, the doctors tell them the risk and suggest treatments that are sometimes very radical.