The Jamais Vu

ja·mais vu:
Jamais vu is a term in psychology (from the French, meaning "never seen") which is used to describe any familiar situation which is not recognized by the observer.
Often described as the opposite of déjà vu, jamais vu involves a sense of eeriness and the observer's impression of seeing the situation for the first time, despite rationally knowing that he or she has been in the situation before.
Jamais vu is more commonly explained as when a person momentarily does not recognize a word, person, or place that they already know.
Jamais vu is sometimes associated with certain types of amnesia and epilepsy.
Theoretically, as seen below, a jamais vu feeling in a sufferer of a delirious disorder or intoxication could result in a delirious explanation of it, such as in the Capgras delusion, in which the patient takes a person known by him/her for a false double or impostor. If the impostor is himself, the clinical setting would be the same as the one described as depersonalisation, hence jamais vus of oneself or of the very "reality of reality", are termed depersonalisation (or irreality) feelings.
Times Online reports:
“ Chris Moulin, of the University of Leeds, asked 92 volunteers to write out "door" 30 times in 60 seconds. At the International Conference on Memory in Sydney last week he reported that 68 per cent of the volunteers showed symptoms of jamais vu, such as beginning to doubt that "door" was a real word. Dr Moulin believes that a similar brain fatigue underlies a phenomenon observed in some schizophrenia patients: that a familiar person has been replaced by an impostor. Dr Moulin suggests they could be suffering from chronic jamais vu. [1]