Background: Although delusion is one of the common symptoms of Alzheimer's disease (AD), the association between cognitive deficits and delusions remains unclear. Considering the heterogeneity of delusion, the correlation may depend upon the type of the delusion. Methods: 142 consecutive first-visit AD outpatients of the Tajiri Clinic (Osaki, Miyagi, Japan) were enrolled in the study. Psychological data included the Mini-Mental State Examination (MMSE), the Cognitive Abilities Screening Instrument (CASI) and the Frequency-Weighted Behavioral Pathology in Alzheimer's Disease Rating Scale (BEHAVE-AD-FW). Correlations to cognitive deficits for each category of delusional content were evaluated. Results: More severe delusion of 'residence is not home' was significantly correlated with a lower total MMSE score and poorer orientation as assessed with the CASI. This type of delusion also correlated to activity disturbances and was weakly associated with affective disturbances. Conclusion: Our findings suggest that the 'residence is not home' delusion is a particular symptom that has a cognitive background, particularly disorientation, and should be discriminated from other delusional phenomena. We should cope with delusions specifying what types of delusions are present since the content of delusions may critically mark the symptomatology of AD. For this purpose, the BEHAVE-AD-FW may be suitable.
- Alzheimer's disease