Norepinephrine connection with anxiety?

Hello. I have panic disorder which slowly developed to agoraphobia. It all started when I entered puberty (14 years). I am now 24, with not psychological abnormalities what-so-ever, not even depression (certified by three different psychiatrists). My anxiety manifests itself without outside stimuli or emotional trouble. People with panic disorder and agoraphobia feel calm at home. From the moment I wake up in the morning, it feels as if I've been attached to an adrenaline IV. The moment my eyes open, my body feels as if it's been dipped into adrenaline - there are absolutely no outside stimuli (I just wake up!). It is so debilitating that I cannot stand noise or even function - again, from the second that I wake up. For 5 years I was on Lexapro and Klonopin, which really helped with anxiety, but never completely cured me.
I just recently had blood tests for thyroid which came back good. My question is - could I have a catecholamine problem?
I was put on Ixel, an SNRI, which absolutely unexpectedly removed my anxiety from scratch. My psychiatrist was amazed, since starting an SNRI usually gives extra anxiety. Sadly, it also made me more aggressive and my heart rate was 110bpm.
From what I've read so far, serotonin acts as a norepinephrine inhibitor, so that may be one of the reasons why it helped.

First off, do you think that a catecholamine imbalance can cause severe anxiety?
What blood tests would you suggest that I have done ? Are norepinephrine blood and urine tests accurate enough?
What are the possible treatments for excess norepinephrine?

[Paxiled]

Whatever the answer to your question, snris work on both serotonin and norepinephrine receptors, so if the snri relieved your anxiety it's very unlikely norepinephrine is causing your anxiety -- by taking the snri you just increased the functioning of it and you reduced your anxiety.  This would suggest that depression is a problem, but who knows?  

[Stan2233]

Hello. Well, neither SSRI "increase" the levels of serotonin and SNRI do not "increase" the levels of norepinephrine. They just don't allow them to break down and keep them in the synaptic cleft.

[Paxiled]

That's why I said increased "the functioning of it," not increased the levels of it.  But it does give you a stronger serotonin and norepinephrine usage than what your body would do normally with it, which is why it works but also why there are side effects.  At any rate, good luck to you.  Over and out.