Delusional perception and delusional notion linked to a perception.

It is a neglected psychopathological fact that Schneider clearly differentiated the delusional notion linked to a perception ("wahrnehmungsgebundener Wahneinfall") from the delusional perception ("Wahnwahrnehmung"). When this distinction is not taken into account, it is very likely that the probability of a false positive rating for the delusional perception is increased. A possible practical aid to help operationalize the differential "diagnosis" between these two symptoms is offered. The section on "delusional" phenomena in Wing's present-state examination is then discussed in the light of these distinctions.