I had really devastating, almost deadly, panic/anxiety issues for almost 2 years. It's hard to describe credibly to anyone who hasnt experienced it, but they were incapacitating, and relentless to the point of making me suicidal.
Seeking help from the medical community was useless, and deepened both the devastation and the sense of hopelessness.
To make a long story short, what helped me was researching the CNS and the brain, and then GABA and glutamate.
This led to more research, and finally stumbling on some info re magnesium's ability to block NMDA receptors and inhibit calcium ion channels.