A panic disorder is characterized by sudden feelings of terror or panic attacks where physical symptoms suddenly occur without any real danger being present. Common symptoms include rapid heartbeat, chest pain, sweating, nausea and feeling like you may lose control. Panic disorders can be caused by stress, trauma, fear of additional attacks or have no identifiable cause. While medication or therapy can help control panic disorders, they are generally considered long-term conditions. Prevention techniques include controlling stress levels, breathing exercises and distraction during attacks. The document provides a personal example of someone with panic disorder experiences frequent panic attacks but is otherwise a normal teenager.