Stress seizures?

My wife was diagnosed with epilepsy about 3 years ago. She was put on keppra which seemed to control it. I only saw her have 1 seizure while we were dating. After we moved in together, the seizures returned with much greater frequency. And, different types of seizures. At first, she would hyperventilate, and stare straight ahead. She would be completely unresponsive to painful stimuli, but would be aware of what was going on around her. These seizures lasted anywhere from 15 minutes to 7 hours. Her neurologist said they were just panic attacks, and discharged her. Then the seizures with convulsions started. She would be unresponsive for about 15-30 minutes with periodic convulsions during this time. It usually started with her passing out. I often mistook it for dozing off until the convulsions started. She had an EEG which showed no epileptic activity even during a seizure. Her neurologist said stress seizure, put her on prozac, and sent her home. The seizures kept getting worse. We tried another neurologist, who also said stress seizures. Then another who said the same thing. Then another. The 4th one put her on lamictal. It seemed to be helping. She went over a month with no seizures. Then they started back last month. These have been much less severe. Only one had convulsions. The rest are like drop seizures. She'll be fine one minute, then suddenly she's face down in the floor. And now she's usually awake in about 10 minutes. What I don't understand is, if these are caused by stress, why do they come when she's not under stress, and not when she is? For example, when she had her last one, we were watching tv. I looked over at her and she was out. However, last summer at our wedding, she was a nervous wreck the entire week. But, no seizures. We've been to 4 neurologists in 2 states. She's talked to psychiatrists. She's tried keppra, prozac, and lamictal. And, nothings changed. Has anyone had any experience with seizures like I've described? If so, what kind of treatment did you get, and how well did it work?