No, but a SAD diet probably will.

Honestly, I think that switching to any diet focused on whole foods, including paleo, would be a positive step in reducing the symptoms of both seizures and bipolar disorder. I was on lamictal for both mood swings as well as to control my epilepsy when I started cutting out processed foods, which eventually led to me being more paleo-minded. What I found and experienced was that the side effects of the Lamictal (mainly the constant headaches) were diminished, and my moods became more stable as well. As long as you take care of your nutrient needs through your diet, and make sure to get enough fats, I feel that you'll have a positive reaction to the changes. Diets high in sugars and caffeine exacerbate both mental disorders as well as seizure disorders. Good luck!