I take a B-Complex with Folate about 1-3 times per week depending on how I'm feeling.
I'm not sure if I've taken B1 by itself directly, but I remember at the point where doctors were investigating what on earth was wrong with me, they started with the vitamin B injections (not sure which B vitamin this was, though)...ugh. Did that like for a month or so, once a week, but I didn't have a seizure for a year. At that point, I was having them happen many times per week at school, which were more focal aware type of things going on. At one point, it seemed there was a year that I only had one or two seizures.
I remember I started taking one vitamin B6 and one vitamin B12 before school every day at home and that reduced the seizures dramatically. That was when I was about 9 years old. It seemed like the problem had basically gone away by the time I was 11 years old.
I don't remember if I was still taking the vitamin B like I was supposed to, but the seizures only worsened. By the time I was 14, I had my first epilepsy problem at school (this stuff always happened at school...seriously). Then, medications were inevitable, but I was glad to not have to take them for those 5 years after being diagnosed.
So, I figure this is all hormone related and influenced because the worst times for me are that one week a month and it's awful at the start and at the end of the menstrual cycle.
I started getting bad nocturnal epilepsy these past few months. It's scary, and horrible. I remembered I wasn't taking my B-Complex again. I had laid off of it because for a time I thought maybe I was getting too much - I was having terrible, vivid nightmares that wouldn't stop and I had so many nightmares in a night that I couldn't rest. It was constantly falling asleep, having a nightmare, and waking up. I stopped the B-Complex and the nightmares became less and less. So, I suppose it was possible to get too much after a point.
I forgot about the B-Complex again for a while. With the nocturnal epilepsy, I started thinking what might help and I took a vitamin B-complex before bed. Now, I don't like doing this because vitamin B wakes the brain up, but I wasn't sleeping good anyway. I felt like for the first time in a while I actually got some sleep without a seizure in the night. I did that for a few nights, then gave it a break, then a few more times with the B-complex.
After a while, I had some scarier issues and my dosage was upped, which has helped me sleep much better, too. However, I still take the vitamin B-Complex at least one a week. Other times, I make sure to take the Folate on a better schedule, because Keppra is known for taking folate from you and I feel that helps. In conjunction, this helps quite a bit.