Biologically, why does hyperthyroidism cause irritability or anxiety?

What biologically happens (preferably step by step) that explains why one results in the other?

I am fighting a particular form of melanoma cancer right now and I’m in the middle of an immunotherapy regimen which is working great. A side effect however is that my immune system got so “jacked up” that besides the cancer cells, it also attacked my thyroid.

In the process, my thyroid reacted by dumping large amounts of thyroxine into my system as it slowly died. The results were severe hyperthyroidism. I lost about 20 lbs, had significant heart palpitations and high blood pressure instantly. I also became super anxious and irritable.

My Endocrinologist told me that the excess thyroxine gives ones metabolism a huge boost which in turn activates the sympathetic nervous system. This is your “fight or flight” response system. For me, I was constantly on edge due to this and as such anxious and irritable. My wife tells me I was a total a-hole FYI.

There are pretty good sites out there for more information. What finally slowed my down was 100mg of prednisone daily for about 6 weeks as my thyroid finally died. Now I am fighting hyPOthyroidism, but I’m almost cancer free so its all good!