I was completely seizure free on 300mg and then I had a GM out of the blue and was put up to 400mgs. Have been seizure free ever since, then the depression hit and was put up to 500mgs 'just in case' and anti depressants. The description of the depression is bang on - up and down like a roller coaster. The SSRI worked for a while then stopped, so changed to an SNRI which also worked for a while and that has stopped. No one's ever bothered to check my pheytoin levels for a while and the psych also never bothered to check up on phenytoin although it's there in my notes. I want to remain seizure free but I hate the depression.