Many people and vets are not aware that low thyroid (even borderline low) can cause fear, moodiness and aggression in dogs. I have had 4-5 dogs with these problems (I rescue "troubled" animals) which tested low thyroid and responded to thyroxine almost immediately. I always send blood to Dr. Jean Dodds, canine endocrinologist and thyroid researcher. Hemopet.org. How many are put down for behavioral problems when it is merely a hormone problem? Cathy Ritlaw, jeranimalsanctuary.org. Please visit my page/animals/petition. Thanks!

I will take note of this as I had not heard of it causing such symptoms in dogs. I have had cats with high thyroid problems so thank you for letting us know.