[Pseudodementia, what are we talking about? Part I: In search of Wernicke's pseudodementia]

The authors explore the history of pseudodementia in the elderly; an issue with growing momentum in a world where life duration expectancy has been constantly growing and the management and treatments of dementias has imposed an equally increasing burden. Although the issue is mainly therapeutic, some of the main tenets of the current approaches rest heavily on historical issues. The invention of the term pseudodementia (Pseudodemenz) is usually credited to Wernicke. However, the exact circumstances and the debates that have accompanied the emergence of the term have never been fully uncovered, and the references are not accurate. Most of the recent literature cites Kiloh as the key influence in structuring the current uses of the term, but the relationship between both sources is not clear.

A research of anteriority has been conducted on the basis of Medline via Pubmed, PsychINFO and google book, using the following keywords: pseudodementia, pseudodementia, depressive pseudodementia, pseudodémence, Pseudodemenz. We have researched the quotations to localize the origin of the concept. Complementarily, we have attempted to clarify the nature of the debates by exploring the relevant German psychiatric literature at the end of the XIXth century and the beginning of the XXth.

We have found that the very first occurrences of the notion appeared in a debate between the following authors: Ganser S.J.M. 1898, 1903; Wernicke C. 1898; Raecke J. 1901; Nissl F. 1902; Jung C.G. 1902, 1903; Stertz G. 1910; Bonhoeffer K. 1911; Schuppius S. 1914. We found that the term Pseudodemenz never appears in Wernicke's written works, although he was credited of its invention by his most direct students. It seems that the term was thought by the time it emerged to have originated in Wernicke's discussion of Ganser's syndrome.

Ganser's syndrome, often defined as carceral psychosis, is a specific hysterical twilight state characterized by "talking past the point" (Vorbeireden), amnesia and hysterical stigmas, in which some trauma was thought to be causative. Wernicke presented it as determined by a "restriction of the field of consciousness", echoing Janet's theory (École de la Salpêtrière). He rejected the twilight characteristic: this differential point seems to have initiated the introduction of the concept of pseudodementia. Raecke argued that such states should not be understood as forms of simulation thus contributing to a heated debate of the time. Referring to Janet's works and expanding the syndrome of "traumatic hysteria", he argued in favor of a specific inhibiting factor which disturbs the process of associations. Jung, refusing Nissl's article dismissing Ganser, Wernicke and Raecke's views, confirmed the hysterical hypothesis. In a new contribution to the debate, Ganser contested Wernicke's differential point, arguing that in Vorbeireden, there was a Benommenheit - some sort of giddiness - and a "superficiality of the contents of consciousness" rather than a limitation of consciousness. It has been rightly argued that Wernicke's view of the pseudodementia issues was mainly related to the debates on hysteria and trauma, and that no relationship with old age symptomatology was established by him. However, we have found that he alluded to at least one case in which such a relationship was hypothesized. Moreover, one should note that Wernicke's views on hysteria included the rather pervasive notion of "hysterical psychosis", exhibiting "allopsychosis", which could include what would nowadays be seen as schizophrenia or psychotic mood disorders.

First of all, the term Pseudodemenz, if it was ever used by Wernicke verbally, never appears in his published works. Besides, the debates concerning Ganser's syndrome, which served as a first paradigm to discuss pseudodementia, were highly influenced by the discussions on traumatic disorders, hysteria and simulation. Finally, although no direct connection is made between disorders of the senium and Pseudodemenz, the fact that Wernicke included both in what he termed "allopsychic disorders" seemed to indicate that some kind of relationship could not be absolutely excluded in Wernicke's mind.