Hyperthyroidism can cause behavior changes. It can also be dangerous.
My 15-year-old, spayed female, Siamese mix cat walks around the house yowling constantly. She sounds just like a cat in heat. She does it day and night. She is otherwise completely normal, eating, drinks the same amount of water, using cat box, the way her fur looks, etc. It is getting on our nerves so badly that my husband is threatening to have her put to sleep. Any ideas on what might be causing this?
I can appreciate why you need help. Without a solution to this yowling you may want yourself put to sleep. There are a few plausible explanations for this behavior but by far the most likely is hyperthyroidism. It’s caused by benign tumors on the thyroid glands, which produce too much thyroid hormone. Aside from their bizarre behavior these poor old cats often lose weight in the face of excessive appetites. Severe heart damage is also a common result of this disease.
The good news is that hyperthyroidism is quick and easy to diagnose with a blood test. Treatment is usually quite safe and effective. Now put down the gun and call your veterinarian.