Non-Cognitive Symptoms and the Diagnosis of Dementia

The current characterisation of dementia as a state of global cognitive failure (DSM-III-R, 1987) cannot differentiate it reliably, in cross-sectional diagnosis, from other states of compromised cognition. This is likely to contribute to both the over- and under-diagnosis of dementia in clinical practice (Marsden & Harrison, 1972; Fleminger, 1975; Ron et al , 1979; Smith & Kiloh, 1981; Garcia et al , 1984; Klein et al , 1985). However, diagnostic discrimination between true dementia and its behavioural phenocopies (e.g. depressive pseudo-dementia, quiet delirium, etc.) can be improved in a number of ways. One such is the longitudinal assessment of symptom-clusters (e.g. those related to memory, personality, and cortical syndromes); another is the inclusion of new symptoms into the definition of dementia. The first of these strategies has been given more attention than the second.