MadDoc is correct about the pathways. I had terrible anxiety off and on for most of my adult life, but ever since I made a concentrated and holistic effort to address it I've basically seen those pathways fall by the wayside.
Like HPPD there's no cure for anxiety, but there are many different treatments that work and if you combine them all you can really begin to make a difference.
For me, I'd say the most important has been diet. I eat a loosely-based paleo diet, no gluten (increases anxiety), potatoes (increases anxiety), excess sugar (increases anxiety) and junk food (increases anxiety). This has worked wonders for me and on days when I don't eat well I can tell. Eating changes your gut and hence your neurotransmitters so there's really no better way to alter your brain chemistry than through eating.
Yoga is also great. It trains your brain and body to handle stress, therefore when stressful situations occur you're more ready to tackle them without worry.
Meditation is also 1A behind food. It's worked wonders for me over the last few years. I really think it's transformed my brain after practicing nearly ever day before bed. I think half the battle of anxiety is not understanding what's happening inside your mind, not being able to take a step back and really examine your thought process. Meditation totally changes this and has entirely rewired my brain for as far as I can tell. I literally don't even think the same way I used to after meditating for two years. I'm much more at peace with myself and my thoughts and am finally an expert at watching things from afar, which I never could do before.
As far as supplements go, I think a B-complex vitamin, magnesium, passion flower, fish oil, and lavender tea have really helped me out. I also hear taurine is good for anxiety as it promotes GABA. The combination of all these has really helped me transform my brain. I haven't had anxiety in about a year now and I think it's largely due to a combination of all this stuff.