I think that different people react differently to medications. If there is a close relative who has been on a mood stablizer then I would take their reaction into account. We had a similiar reaction with Lamictal, difficult child developed hives, we stopped all medications untill the rash was completely gone, restarted Lamictal and no more rash. FWIW, difficult child did horribly on depakote and lithium. He also did not tolerate stims well alone, but seems to do well on Daytana 10mg as long as he is stable on his Lamictal.
husband is on Lamictal also (he was diagnosed after difficult child). husband was on geodon and developed tardive dyskensia, and now is on Trileptal and Lamictal. husband's psychiatrist asked for a list of medications that difficult child has tried and how he reacted.
