No one who has ever been tormented by prolonged bouts of anxiety doubts its power to paralyze action, promote flight, eviscerate pleasure, and skew thinking toward the catastrophic. None would deny how terribly painful the experience of anxiety can be. The experience of chronic or intense anxiety is above all else a profound and perplexing confrontation with pain.

— Barry E. Wolfe, Understanding and Treating Anxiety Disorders: An Integrated Approach to Healing the Wounded Self (Washington, DC: American Psychological Association, 2005).