First of all, panic disorder shows itself in panic attacks that come at unexpected times and recur fairly frequently. Also, people that have these attacks are usually so traumatized by them that they develop a fear of having another. A panic attack is typically characterized when a person is having and overwhelming sense of panic that is also combined with shortness of breath and an unusually rapidly beating heart. Another part of this disorder includes the constant worry of having a medical condition that medical professionals cannot find, and this worrying usually continues for months.It's possible to have panic disorder without agoraphobia, but the two are commonly connected.
Agoraphobia is usually combined with panic disorder and it is the fear of having another attack along with extreme avoidance of any situation where one could have another panic attack. There would be an extreme anxiety and fear of any place where the person has had a panic attack or believes strongly that they can have another panic attack. This fear is extreme and no amount of convincing is enough for them to overcome this fear. Eventually the fear becomes generalized to include nearly everything outside of home, especially crowded locations, as these are especially prone to panic attacks.