Panic Disorder (PD)

In PD the person suffers from brief attacks of intense terror and apprehension, often with trembling, shaking, confusion, dizziness, nausea and difficulty breathing. PD can be triggered by stress, fear or exercise, and the cause is often not apparent. The person may feel like he is dying, going crazy or having a heart attack. 

Panic Disorder with agoraphobia (PDA) 
PDA happens when an individual experiences an unexpected panic attack. The person then has substantial anxiety over having another panic attack; and then might rarely or never leave their home in fear of  having another attack.