Depression and dementia, among the most common conditions in clinical practice, sometimes coexist, sometimes succeed each other, and often confuse clinicians. In the present paper, the clinical concept of 'depression-dementia medius' (which includes pseudodementia and depression in Alzheimer's disease as exemplars) is proposed, in reference to Janet's concept of psychological tension. Because psychosomatically complex human lives are always in a state of dynamic equilibrium, it seems sensible to propose that pseudodementia and depression in Alzheimer's disease are located within a spectrum extending from depression without dementia symptoms to dementia without depression. From the Janetian viewpoint, pseudodementia is regarded as uncovered latent dementia as a result of reduced psychological tension. Dementia is more than a fixed progressive condition under this view, and is a manifestation of dynamic mental activities. Characterizing these entities through perspectives such as psychological tension may yield deep insights in clinical practice.
© 2011 The Authors. Psychogeriatrics © 2011 Japanese Psychogeriatric Society.