Phobia
With phobias, a person fears something which is not really dangerous, or which is not anywhere near as dangerous as the person believes it is.  For example, many humans fear spiders.  However, a person with a phobia of spiders might panic when even thinking about a spider, refuse to leave home because they are too afraid of seeing a spider, or spend hours of each day making sure there are no spiders in their home.  People with phobias realize that their anxiety is much more severe than normal fear would be.