A<unk>  is a medical symptom which can have a psychological or a physiological cause. Psychological causes can include an anxiety disorder, depression, panic disorder, or bipolar disorder. Physiological cause could include a pheochromocytoma, heart attack, blood transfusion, or anaphylaxis.
Sense of impending doom
Fear of trains
Death from laughter
Callous and unemotional traits
Mindfulness
Fear of flying
Emotional detachment
Emotional lability