13 yr old son with epilepsy and OCD

About 6 weeks ago I found my 13 yr old son unconscious in the middle of a major seizure (grand mal). Until that day I didn't know he was epileptic. He had only seized once before when he was 7 yrs old during a very high fever. We thought it was a freak thing and would never happen again. Now after three EEGs we have discovered that he has frequent seizure activity in his brain. His neurologist thinks the OCD could be linked to this extra electrical activity. My son is now on 1500 mg of Depakote. He has always been anxious and sensitive, but he has been struggling with OCD for about 2 years now. The OCD began getting much worse about 3 months before his seizure. He fears he will develop diabetes (he is very thin and active) so he obsessively monitors his food intake. Eggs are the magic food to him. If he eats 2 eggs a day, he thinks he will not get diabetes. He also fears that if he consumes anything with high fructose corn syrup he will get diabetes, so he reads has to read and re-read the ingredients on every package of food. He eats sweets occasionally but only if he thinks he has eaten enough protein and vegetables beforehand. Usually he has to ask for reassurance over and over before he will eat even 1 or 2 cookies. He also fears germs, so he washes and rewashes his hands while reading the soap container. He reads things forwards and backwards several times to be sure he is using the right soap. He carries a small bottle of hand sanitizer gel with him at all times. My son also is obsessive about his bedroom. It is always in a certain "perfect" order and he checks and rechecks his floor and walls for spiders and dust specks several times before going to bed. This may take hours. Now, here's what I notice about the anti-seizure med (depakote) and the OCD: Every time we increase the depakote his OCD subsides for awhile (we started at 500 mg per day for a week and increased to 750 mg for a week, to 1000mg for a week and then to 1500 mg over a period of 4-5 weeks). After he adjusts to the new level, the OCD returns, but is not as intense as before. I find this very interesting. The last increase to 1500 mg seemed to take away nearly all his OCD for about a week. He wasn't obsessing hardly at all and was having fun. Now the OCD is coming back, but it's not as bad. He still worries about the same things, but is more able to address his fears. However, when he's tired he can't seem to say "no" to the obsessions. Last night he was doing his nighttime bedroom checking rituals until after 2 AM. We have been in therapy for the OCD with little result other than an increased awareness and language when discussing it. If the depakote doesn't help with the OCD, our neurologist will prescribe an SSRI of some kind. My concern: the best anti-anxiety meds (Luvox, Zoloft) lower the seizure threshhold. Is this anything to worry about?