Recently published international dementia consensus statements suggest that each patient fulfilling the criteria of the dementia syndrome should be investigated in an effort to establish a probable or possible single-disease diagnosis.1 In general, these consensus statements claim a disease model for dementia based on monocausality. Alzheimer disease is assumed to result primarily from neurodegenerative cell loss mediated by senile plaques and neurofibrillary tangles. Similarly, other types of dementia (eg, vascular dementia, Lewy body dementia, and frontal lobe dementia) are modeled on the hypothesis of monocausality. Herein, we introduce a new model of “multicausality” of dementia and suggest a 2-step diagnostic process for dementia based on multicausality that may be more useful in both clinical practice and in research than the use of clinical disease labels.