Back in 2011, I went to the doctor because I was having frequent bouts of vertigo, which often went hand-in-hand with the panic attacks that had become a several-times-a-day occurrence. It was quite embarrassing when it would happen while I was talking to someone. I would freeze up, unable to process anything they were saying. Fear of having these episodes exacerbated my social anxiety, and my anxiety in general. I felt awful, day in, day out. The first thing my doctor did was run the gamut of tests, including my thyroid. A few days later, I got a phone call from my doctor's office, telling me that everything was fine except for my thyroid stimulating hormone, which was through the roof. They told me to come back for a retest to verify that the number really was that high, since it was so far off the chart. During that visit, my doctor told me that it's no wonder that I'm feeling awful if my TSH really is that high because it means that my thyroid is probably sleeping on the job. He also told me that hypothyroidism absolutely can cause anxiety, panic attacks, heart palpitations, and insomnia (which was something else that I'd brought up during the first visit), even though most tend to associate it more with hyperthyroidism, just as you can hyperthyroid can cause fatigue and depression (which are more commonly associated with hypothyroidism). As soon as the second test came back, I got another call telling me that my TSH was actually higher than it was the first time, and that my doctor had written me a prescription for Synthroid (thyroid replacement hormone pills).
I've been on Synthroid for nearly 5 years, and it seems like my anxiety has eased significantly (for the most part), though he did also put me on clonazepam (the generic of Klonopin) to help with the panic attacks and general anxiety, as well as the insomnia; I've been taking a low dose of that for the same length of time. I've had my ups and downs as my levels still fluctuate somewhat (though my TSH has been much more reasonable since after the first year of starting treatment). I have to go in for re-tests every few months, and have my dosage readjusted accordingly. I think I'm fortunate that my doctor included thyroid function in the testing, since I've heard of several doctors who won't even consider testing the thyroid in someone so young (I was 23 at the time).
As far as physical and other mental symptoms go, I've found some improvement there as well. Though I still do struggle with chronic fatigue due to another underlying condition, I definitely have seen some improvement; I can exercise much longer and more intensely. I used to be cold all the time, but not anymore. My depression is not nearly as bad as it used to be. I seem to have far more confidence, perhaps because I'm no longer worried about an "embarrassing episode". I used to have frequent heart palpitations, but those have become a rarity. I'm sure there are several more symptoms that aren't immediately coming to mind, but hopefully this gives you an idea how the treatment has been working.
Well, it looks like I just wrote a novel about my thyroid! I realize that your concern is hyperthyroidism (whereas I'm talking about hypothyroidism), but I hope my story can help you in some way. I hope that you can find an answer soon. Best of luck!