Pseudohallucinations versus true hallucinations in prodromal psychosis: does it really matter?

摘要

Sir: According to the traditional accounts of European psychiatry, true hallucinations are apparent perceptions of an external object in the absence of adequate sensory stimuli. Conversely, Sims states that Kandinsky and Jaspers described pseudohalluci-nations as a separate form of perception from true hallucination. Pseudohallucination is a perceptual experience that is figurative, not concrete or "real," is located in inner subjective space, and is perceived with the "inner" ear (or eye) (Table 1). In other characteristics, pseudohallucinations are more like true hallucinations than fantasy. Thus, pseudohallucination may have definite outline and vivid detail, it may be retained for some time, and it is not deliberately evoked. Jaspers stressed that there is a gradation from the more fully formed pseudohallucination to vivid imagery but that there is an absolute distinction between hallucination and pseudohallucination because of the inner location of the latter. As a consequence of these original speculations, it is a common belief that pseudohallucinations do not have the same psychiatric significance as true hallucinations, and thus clinicians expend some clinical effort to distinguish the two. True hallucinations are thought to be always indicative of a morbid mental state such as psychosis, while pseudohallucinations are thought to be of less diagnostic significance and not necessarily psychopathological. However, pseudohallucinations may be an attenuated and subtle expression of an evolving psychosis. There have been no previous studies of the degree to which pseudohallucinations are predictive of the subsequent development of psychosis.