As the name suggests, panic disorder is expressed in panic attacks which occur without warning, accompanied by sudden feelings of terror. Physically, an attack may cause chest pain, heart palpitations, shortness of breath, dizziness, abdominal discomfort, feelings of unreality and fear of dying. When a person avoids situations that he or she fears may cause a panic attack, his or her condition is described as panic disorder with agoraphobia (fear of open or public places).

Excerpts from CMHA National web site – Panic Disorder