There are 5 main types of anxiety disorders: Panic Disorder, Post-Traumatic Stress Disorder (PTSD), Obsessive-Compulsive Disorder (OCD), Social Phobia, aka Social Anxiety Disorder, Generalized Anxiety Disorder (GAD).

I've had panic attacks, and they're terrible: Sweating, fast heartbeat w/ chest pain, blurred vision, weak legs, and an overall thinking/feeling that you're going to die and wanting to flee the situation.

I'm just guessing, but panic attacks may be related to the fight-fright-flight syndrome.