Karl Jaspers and the Genesis of delusions in Schizophrenia

In his General Psychopathology, Karl Jaspers identifies two stages in the genesis of delusions in schizophrenia. The first is a set of primary subjective experiences, which he encompasses under the rubric of “delusional atmosphere,”1 building upon F.W. Hagen’s construct of “delusional mood.”2 The second is the patient’s “working through” those experiences, sometimes “calling for the full strength of an intelligent personality,”1 which leads to delusional ideas. The content of delusions— Jaspers adds—“strikes one as a symbol for something quite different,”1 “is certainly not meant literally and is quite differently experienced from similar content in the case of a person we can fully understand.”1 “It is certainly possible to wonder whether the patients have found any content adequate for their actual experience.”1 In this issue of the journal, Mishara and Fusar-Poli3 propose that Kapur’s model of “aberrant salience”4 may represent a “bridge” between a revised version of the dopamine hypothesis of schizophrenia5 and Jaspers’ construct of delusional atmosphere. Abnormal striatal dopamine firing would lead to an aberrant assignment of salience to neutral stimuli and consequently to the emergence of delusional mood.1 One could argue, though, that the overlap between the experiences reported by Kapur in his seminal paper4 and those described by Jaspers under the heading of delusional atmosphere1 is only partial. Common elements are the patients’ experience that “something in the world around them is changing, leaving them somewhat confused and looking for an explanation”4 and their feeling that “there is some overwhelming significance in this”4 or that certain objects or persons “signify something,” although initially “nothing definite.”1 However, absent in Jaspers’ description of delusional atmosphere is Kapur’s emphasis on the increased intensity of perceptions (“my senses were sharpened,” “sights and sounds possessed a keenness that I never experienced before,” “my senses seemed alive ... things seemed clearcut,” “my capacities for aesthetic appreciation and heightened sensory receptiveness ... were very keen at this time”).4 Experiences of this kind are included by Jaspers in another section of General Psychopathology (“changes in intensity of perception”).1 In delusional atmosphere, the intensity of perception is not modified (“perception is unaltered in itself,” “perception itself remains normal and unchanged,” “sensory richness is not essentially changed”)1 and the change in the environment is experienced as quite subtle (“there is some change which envelops everything with a subtle, pervasive, and strangely uncertain light”).1 Furthermore, not prominent in Kapur’s account of aberrant salience, but emphasized by Jaspers in his description of delusional atmosphere, is the “affective” component of the experiences: objects, persons, and events appear “eerie, horrifying”; patients feel that “there is something suspicious afoot”; “a distrustful, uncomfortable, uncanny tension invades them”; they “suffer terribly,” because—Jaspers argues quoting Hagen—“no dread is worse than that of danger unknown.”1 Not surprisingly, the final outcome of delusional atmosphere is often represented by convictions of being persecuted, attacked, or conspired against, which might be more difficult to explain if the primary experience were just of an exaggerated salience of percepts. So, there is some overlap between Kapur’s description of aberrant salience and Jaspers’ account of delusional atmosphere, and the common elements may indeed point to an abnormal striatal dopamine firing. But there are also other elements in Jaspers’ description—the “strangely uncertain light” enveloping everything, the feeling that there is “something suspicious afoot,” the “distrustful, uncanny tension”—that seem to point to an abnormal dopamine firing at the level of limbic areas such as the amygdala and the hippocampus,6,7 whose involvement in ultra high-risk states and in first-episode schizophrenia has been actually reported by several neuroimaging studies.8–10 Obviously, Jaspers’ construct of delusional atmosphere remains of great relevance to psychopathological enquiry and neuroscientific research. However, several assumptions he makes concerning that set of experiences, or patients’ “working through” them, have been recently questioned. Schizophrenia Bulletin Advance Access published January 11, 2013