My son has be diagnosed with Migraines and is taking Amitriptyline. His personality has changed where he is angry most of the time. Could this be a side affect of the Amitriptyline, or is this most likey because of the Migraines? His Migranes started about 9 months ago and he is 14 years old. He has been taking Amitriptyline for about 3 months and it seemed to help but he has recently had a number of Migraines since school has started back up.