What type of diseases cause seizures under extreme stress?

I know someone who gets seizures every time he gets angry,
AVM maybe? He won't get tested.

Epilepsy can be affected by stress, among other things, and result in increased seizures. Also some psychiatric meds also lower the seizure threshhod, like Wellbutrin, and can lead to increased frequency of seizures. Additionally, withdrawal from benzodiazepines (anxiolytic withdrawal) can cause seizures if high doses are stopped abruptly.
Another purely psychiatric disorder, called Somatoform Disorder, may have psychogenic seizures as a component. These seizures are not epileptic and are purely psychological, but are not faked. They look just like epileptic seizures but there are no abnormal EEG's and they can only be distinguished from epileptic seizures via EEG's and testing by a neurologist. (Trust me here-I had a very large client fall on me during one once and we discovered they were psychogenic only after we sent her for a neuro eval at a specialized clinic for seizures) They are actually dissociative symptoms and represent a response to traumatic events initially, but become triggered by intense emotional experiences later. There is usually amnesia for the events prior to the seizure and during it and there is no aura.

I have juvenile mycholonic epilepsy (not sure of spelling), but his sounds more severe than that. He might really want to get tested. With medicine that could be controlled.

Epilepsy can cause seizures under stress, it is the only disease I can think of. Like most mental diseases there are varying degrees of severity. This case looks like a mild case of epilepsy. My brother has epilepsy and it seems to "come back" when he's stressed out. It's no big deal and can be treated with preventative medication that normally has very few if any side effects. You should see a neurologist who could tell you more.

http://www.aafp.org/afp/20050901/849.pdf
http://www.aafp.org/afp/20050901/849.htm...
http://www.epilepsyfoundation.org/answer...
http://www.emedicine.com/neuro/topic403....
http://www.epilepsy.com/articles/ar_1112...
http://www.emedicine.com/neuro/byname/ps...
http://www.emergemd.com/bniq2/article.as...
http://www.canine-epilepsy.com/underlyin...
http://www.nlm.nih.gov/medlineplus/seizu...
http://www.emedicine.com/neuro/topic403....

what he has is this is called nonepilepic seizures and if he gets angry and has a seizures it sound like panic attacks. I heard of this kind of seizure before it is not epilepsy but it does look like it. they treat it by having him go to shrink and maybe put him on depression medicion. This is why he won't get tested. if you want more information I will give you what I can I gave you some links that would help you let me know if I can help you further.

Tell him to count backwards from 10, whenever he starts feeling angry (it interrupts the process): say that you used to get angry before, but since adopting this method, you don't have any more problems with that. Little white lies are acceptable, to help others.