Delusional Perception Revisited

Delusional perception designates a sudden, idiosyncratic, and often self-referential delusion triggered by a neutral perceptual content. In classical psychopathology, delusional perception was considered almost pathognomonic for schizophrenia. Since delusional perception has been erased from ICD-11 and always been absent in DSM, it risks slipping out of clinical awareness. In this article, we explore the clinical roots of delusional perception, elucidate the psychopathological phenomenon, and discuss its two predominant conceptualizations, i.e., Schneider's well-known two-link model and Matussek's lesser known one-link model. The two-link model posits that delusional perception amounts to an abnormal interpretation of an intact perception, whereas the one-link model posits that the delusional meaning is contained within a changed perception. Despite their differences, both models stress that delusional perception is a primary delusion that takes place within an altered experiential framework that is characteristic of the psychopathological Gestalt of schizophrenia. We discuss the role of delusional perception in future psychopathological and diagnostic assessment and argue that such assessments must be conducted in comprehensive manner, eliciting the psychopathological context within which symptoms and signs are embedded. Finally, we discuss the compatibility of the two models of delusional perception with contemporary cognitive models on delusion and cognitive psychotherapeutic approaches.

Behind the opaque curtain: A 20-year longitudinal study of dissociative and first-rank symptoms in schizophrenia-spectrum psychoses, other psychoses and non-psychotic disorders

BACKGROUND

Depersonalization and derealization are currently considered diagnostically distinct from first-rank symptoms (FRS) seen in schizophrenia-spectrum psychoses. Nevertheless, the lived experiences of these symptoms can be very similar phenomenologically.

AIMS

To investigate the interrelationships between depersonalization, derealization and FRS in individuals with different types of psychotic and non-psychotic diagnoses.

METHODS

The Chicago Follow-up Study was a prospective longitudinal research program designed to study psychopathology and recovery in psychiatric disorders consisting of 555 participants, who were recruited at index hospitalization and studied over six follow-up timepoints at approximately 2, 4.5, 7.5, 10, 15, and 20 years later. The primary clinical indices were depersonalization, derealization and Schneiderian FRS that were measured at index hospitalization and at each subsequent follow-up.

RESULTS

62.8% of participants had at least four follow-ups. There were significant differences in the course and chronicity of depersonalization, derealization and first-rank symptoms across the three diagnostic groups. For the whole sample, derealization was significantly associated with FRS at 2-, 4.5- and 7.5-year follow-up timepoints whereas depersonalization was related to FRS from 10-year follow-up to 20-year follow-up. In participants with schizophrenia, overall depersonalization was more often associated with passivity phenomena whereas derealization was more often associated with overall delusions. There was also a significant effect of time on the associations between depersonalization, derealization and FRS across follow-ups.

CONCLUSIONS

Depersonalization and derealization should be viewed as transdiagnostic phenomena that are associated with FRS psychopathology along a continuum, although they are more closely associated with schizophrenia-spectrum psychoses.

A major flaw in the diagnosis of schizophrenia: what happened to the Schneider's first rank symptoms

Kurt Schneider introduced in the definition of the first-rank symptoms (FRS) the criterion that, where unequivocally present, the FRS are always psychological primaries and irreducible. This criterion, grounded on 'phenomenology' (description of subjective experiences), cannot be applied, according to Schneider, to delusions, either two-stage FRS delusional perception, or second-rank delusional notions. The Schneider's key criterion was neglected since the initial adoption of the 'Schneider's FRS' in the subsequent international literature (e.g. PSE, RDC, DSM, and ICD). The 'Schneider's FRS' (e.g. thought insertion, thought withdrawal, passivity, and influence) were persistently equivocated as 'delusions', in spite of the Schneider's FRS exclusion criterion. The internationally equivocated 'Schneider's FRS' (only homonymous of the original 'Schneider's FRS'), were eliminated in the DSM-5 and de-emphasized in ICD-11. However, the diagnostic value of the original 'Schneider's FRS', assessed on the basis of the strict compliance with the Schneider's criterion for their definition, was never determined. The 'damnatio memoriae' of the original Schneider's FRS may be premature. The definition and assessment of the 'experienced' symptoms of schizophrenia, only directly observed and reported by the patients, represent a specific, crucial, irreplaceable domain of psychopathology, to be carefully distinguished from the domain of the 'behavioral' symptoms observed by the clinician. Contemporary psychopathology research is aware of the absolute need for psychiatry to enhance precision and exactness in the definition of the experienced symptoms of schizophrenia, through the formulation of unequivocal inclusion and exclusion criteria (descriptive micro-psychopathology), in order to determine their value in research and care.

Speaking-Induced Suppression of the Auditory Cortex in Humans and Its Relevance to Schizophrenia

Speaking-induced suppression (SIS) is the phenomenon that the sounds one generates by overt speech elicit a smaller neurophysiological response in the auditory cortex than comparable sounds that are externally generated. SIS is a specific example of the more general phenomenon of self-suppression. SIS has been well established in nonhuman animals and is believed to involve the action of corollary discharges. This review summarizes, first, the evidence for SIS in heathy human participants, where it has been most commonly assessed with electroencephalography and/or magnetoencephalography using an experimental paradigm known as "Talk-Listen"; and second, the growing number of Talk-Listen studies that have reported subnormal levels of SIS in patients with schizophrenia. This result is theoretically significant, as it provides a plausible explanation for some of the most distinctive and characteristic symptoms of schizophrenia, namely the first-rank symptoms. In particular, while the failure to suppress the neural consequences of self-generated movements (such as those associated with overt speech) provides a prima facie explanation for delusions of control, the failure to suppress the neural consequences of self-generated inner speech provides a plausible explanation for certain classes of auditory-verbal hallucinations, such as audible thoughts. While the empirical evidence for a relationship between SIS and the first-rank symptoms is currently limited, I predict that future studies with more sensitive experimental designs will confirm its existence. Establishing the existence of a causal, mechanistic relationship would represent a major step forward in our understanding of schizophrenia, which is a necessary precursor to the development of novel treatments.

The Two Faces of First-Rank Symptoms

Recently, there has been renewed interest in Schneider's first-rank symptoms (FRS) of schizophrenia, thanks in part to a meta-analysis of their diagnostic accuracy, which deserves much credit for its methodological rigor. Conceptualising FRS as a diagnostic test whose performance can be measured in terms of sensitivity and specificity involves some issues that require reflection. First, the full adequacy of sensitivity as a measure of diagnostic accuracy for FRS might be questioned. However, it is conceptually acceptable, though FRS are at a disadvantage as compared with many other psychiatric "diagnostic tests" that should have perfect sensitivity under ideal conditions. Also, from a psychopathological perspective it may well be argued that FRS cannot be conceptualised as a simple, inexpensive diagnostic test suitable for screening purposes; however, the history of the concept reveals some reasons why it may be legitimate to view them this way. While no other relevant study has appeared after the publication of the meta-analysis, data on a further 166 patients from a study that could not be included due to incompletely reported data were located. This brought the total to 4,236 patients from 17 studies on the ability of FRS to differentiate schizophrenia from other psychoses. The resulting summary estimates of sensitivity, specificity and positive and negative likelihood ratios are 60.2%, 75.9%, 2.50, and 0.52, respectively. FRS have a kind of double nature, as they can be legitimately considered as belonging to both a sophisticated framework grounded in phenomenological psychopathology and an eminently pragmatic framework grounded in clinical epidemiology. When FRS are conceptualised as simple clinical indicators that require low levels of inference, the available estimates of their diagnostic accuracy are a fairly valid appraisal of their performance and usefulness, and suggest that FRS have some value in differential diagnosis. However, when FRS are conceptualised as profoundly anomalous experiences that can be properly identified and evaluated only by using a phenomenological approach, these estimates can hardly be seen as a valid evaluation of their diagnostic significance. Phenomenologically informed studies are needed to address this research gap.