#8 – Fregoli Delusion
Referred to as the delusion of doubles, an individual with Fregoli syndrome thinks that different people are actually only just one person. Sufferers of this condition usually believe that they are being persecuted by one single person who keeps on changing his or her disguise and appearing as a different person each time.
So, a person may believe that he is being followed by a single person, who keeps on taking the form of someone he knows personally. It is believed that Fregoli delusion occurs due to a brain lesion. Just like Capgras Delusion, this one is also believed to be a breakdown of normal face perception.