Agoraphobia is also defined as "a fear, sometimes terrifying, by those who have experienced one or more panic attacks". In these cases, the sufferer is fearful of a particular place because they have experienced a panic attack at the same location at a previous time. Fearing the onset of another panic attack, the sufferer is fearful or even avoids a location. Some refuse to leave their homes even in medical emergencies because the fear of being outside of their comfort areas is too great.