Read the following passage and answer the questions that follows:

Panic disorder is defined and characterized by the occurrence of unexpected panic attacks. The person having panic disorder experiences recurrent unexpected attacks and must have been persistently concerned about having another attack. Most of the symptoms of panic attack are physical, although there are some cognitive symptoms also. Panic attacks are brief and intense with symptoms developing abruptly and usually reaching peak intensity within a short period. Panic attacks are often unexpected or uncued. They sometimes occur in situations in which they might be least expected such as during relaxation or during sleep. People suffer from panic disorder with or without Agoraphobia. In many studies gender difference has been found on prevalence of panic disorder. Once panic disorder develops it tends to have a chronic and disabling course. People with panic disorder have one or more additional diagnosis. It is estimated that 30 to 50 percent of people with panic disorder develops some serious other disorders.