14. Capgras Delusion
The Capgras Delusion is completely insane and was coined by French psychiatrist Joseph Capgras. It defines someone who holds a delusion that a friend, spouse, parent, or a close family member such as a pet has been replaced by an identical imposter. While it might seem strange, this is a completely real psychological problem people have faced. Officially, it belongs to various similar issues under the spectrum of the “delusional misidentification syndrome.”

This is an issue where a person misidentifies people, places, and even objects. Some believe that time has been warped or substituted too. It can be pretty mild for some and quite chronic in others. How could this influence a real zombie apocalypse, you ask? Simple. What if this delusion was possibly weaponized, causing people to believe everyone they know to be an imposter? They could go on a killing spree, appearing to victims as mentally out of it the entire time.