Anxiety
The philosopher Søren Kierkegaard, in "The Concept of Anxiety" (1844), described anxiety or dread associated with the "dizziness of freedom" and suggested the possibility for positive resolution of anxiety through the self-conscious exercise of responsibility and choosing. In "Art and Artist" (1932), the psychologist Otto Rank wrote that the psychological trauma of birth was the pre-eminent human symbol of existential anxiety and encompasses the creative person's simultaneous fear of – and desire for – separation, individuation, and differentiation.
Anxiety sensitivity
Harvard's Richard McNally, Florida State's Norman Schmidt, and University of Houston psychologist Michael Zvolensky published research that established the validity of anxiety sensitivity. George Washington University psychologist Rolf Peterson, and Yale's Wendy Silverman, extended the anxiety sensitivity concept to children.