A Short Note on Pseudo-Hallucinations

¹ Bethlem Royal and the Maudsley Hospitals, Denmark Hill, London, S.E.5

The difficulty in delimiting the term pseudo-hallucination springs partly from the clinical difficulty in eliciting shades of subjective experience in a mentally disturbed person, and partly from the different ways in which the term `hallucination' is used. American textbooks use hallucination in its broad, lay sense, to cover dreams, hypnagogic experiences and other forms of 'imagery'. If hallucination is used in this broad sense, pseudo-hallucination can have no meaning except as a particular variety of hallucination. That would involve a confusing use of the prefix, not in accordance with its use in such terms as pseudo-dementia and pseudo-hypertrophy. If hallucination is used in the restricted sense, as defined above, then there is a proper place for pseudo-hallucination. In that event however no term is left to cover other subjective sensory experiences (tinnitus etc.) which are also interpreted normally. This absence of a term has been noted by Curran and Partridge, who say (page 65) that sensations due to a disturbance of the apparatus of sense (e.g. from a detached retina) should be distinguished from hallucinations and illusions. It is the absence of such a term that makes necessary the use of hallucination in its broad sense.

Some clinical value can be assigned to pseudo-hallucinations as defined above, principally in that they may help in the differential diagnosis from schizophrenia of depressive psychosis, obsessional states or histrionic behaviour. Against this, however, must be set the view that hallucinations are not of themselves a very important diagnostic sign of schizophrenia and become so only by virtue of their association with more fundamental symptoms (Slater and Roth, page 239). Morever, because of the fluctuating and partial nature of insight, it is often not possible to say with conviction that insight is fully present or absent. It might therefore be considered more profitable to think in terms of the degree of insight, as proposed by Freedman and Caplan (page 567). If that procedure is adopted, then the concept of pseudo-hallucination becomes largely superfluous.