Few studies have examined the relationship between behavioral and psychological symptoms of dementia (BPSD) and neuropathology. Bondareff (1996), who summarized recent work on the subject, concluded that there is no known persecutory, erotomanic, or other specific delusional, illusionary, or hallucinatory center in the brain. Thus, cliniconeuropathologic correlations to BPSD cannot be assumed, because this would require linking complex symptoms to a single, circumscribed alteration of one neuroanatomic area, or one neurotransmitter system, or even one type of histopathologic alteration, regardless of its location. Traditionally, BPSD have been investigated as if they were psychopathologically and neuropsychologically independent of the patient's cognitive disturbances. This may have led to the modest results of some studies. Interestingly, several early studies postulated innovative hypotheses on the neuropathology of BPSD, and sought to verify those hypotheses.