What would be the symptoms portrayed by a 3 1/2 year old if he has hyperthyroidism? My daughter has been diagnosed with hyperthyroidism. Her son has been having huge mood swings,itching, clearing his throat loudly, is loving, sweet, seems smart and more mature than his age but has continuously been becoming more and more mean, hitting, kicking, pinching, biting, throwing things at family, walls, saying he does not have to listen to us, he does not love us, etc., etc.! He is in constant motion, running around, getting into everything, totally wild. Then, all of a sudden he can become loving , wanting his cuddling, telling us how much he loves his family. Should he be checked to make sure that he has not developed hyperthyroidism? Sincerely, Grandma Kathy ( Retired RN and Concerned Grandma)