Physical symptoms include rapid and pounding heartbeat, pulsing arteries especially in the head and neck, shortness of breath, hyperventilation, trembling, sweating, generalized bodily weakness, and light-headedness. Panic attacks represent the maximum possible state of anxiety and often, especially before their true nature is understood, result in visits to the hospital emergency room and even 911 calls for medical assistance by people who believe that they are about to die or go crazy. There is a considerable degree of variation among normal individuals in their proneness to anxiety, with some people seemingly always calm, unruffled and laid back no matter what happens to them, and others hyperactive, jumpy, apprehensive and fearful even when things are going well for them. Inborn and sometimes genetic factors probably play a significant role in such differences. Almost all psychiatric or psychological problems, conditions and illnesses are accompanied by some degree of anxiety as a nonspecific accompanying feature.
People suffering from depression, for example, are very commonly anxious as well.
Panic disorder consists of sudden and usually unprovoked attacks of overwhelming anxiety as described above. Agoraphobia is a condition often associated with panic attacks in which the individual is uncomfortable or anxious in public places or out of their own home. Flashbacks, nightmares, emotional numbing and other symptoms may be present. Social phobia may take the form of intense performance anxiety or stage fright well beyond the range of normal and sufficiently severe to interfere with the individual's life and activities. Another form of social phobia causes the person afflicted to be markedly uncomfortable around other people and resembles an unusually severe and at times disabling form of shyness.