Yes. My first suggestion is to go and have her blood tested for allergies. Before you limit anything out of her diet. It will not show up if you have taken it out of her diet. Make sure she gets the blood test (the scratch test is basically useless).
Casein and Gluten are huge HUGE contributors to behavior. Have you watched her reaction after she has eaten anything with milk protein in it? Does she have more mood swings shortly after she has had anything with milk in it? Also watch Wheat. See what happens to her after she has had something with wheat.
My husband was just diagnosed with a wheat, cows milk, egg white allergy. We found out that all of his passing out, psoriasis and other body issues has all stemmed from this allergy. His parents had him in OT, the school wanted to put him into special classes because he was not able to focus, they had him on psoriasis medicine (which causes cancer if used for a long period of time), etc. etc.
My oldest son was diagnosed with a wheat allergy. He would get frustrated and not be able to handle anything. He could not sit still, and there were days last year where he would all of a sudden stand on his chair in class. We took wheat away and it was as if I had a completely different child.
There is a cookbook out there, I have not checked it out yet, but it is called Casein and Gluten Free cookbook for kids with Autism. Well we know our kids don't have autism, but to have a cookbook with those good recipes in it the name doesn't matter.
Before medicine try and see if they'll do a test for you. It is not that expensive and the switch is, after a few weeks at it, not that hard to do.