What Kurt Schneider Really Said and What the DSM Has Made of it in Its Different Editions: A Plea to Redefine Hallucinations in Schizophrenia

Kurt Schneider has played a leading role in shaping our current view of schizophrenia, placing certain manifestations of delusions and hallucinations at the center of the disorder, especially ideas of persecution and voice-hearing. The first part of this review summarizes Schneider's original ideas and then traces how the different editions of the DSM merged aspects of Kraepelin's, Bleuler's, and Schneider's historical concepts. Special attention is given to the transition from the DSM-IV to the DSM-5, which eliminated much of Schneider's original concept. In the second part of the article, we contrast the current definition of hallucination in the DSM-5 with that of Schneider. We present empirically derived arguments that favor a redefinition of hallucinations, much in accordance with Schneider's original ideas. We plea for a two-dimensional model of hallucinations that represents the degree of insight and perceptuality, ranging from thoughts with full "mineness" via perception-laden thoughts and intrusions (including "as if" experiences") to hallucinations. While we concur with the DSM-5 that cognitions that are indistinguishable from perceptions should be labeled as hallucinations, we suggest expanding the definition to internally generated sensory phenomena, including those with only partial resemblance to external perceptions, that the individual considers real and that may lie at the heart of a subsequent delusional superstructure.

Phenomenological and Cognitive Features Associated With Auditory Hallucinations in Clinical and Nonclinical Voice Hearers

BACKGROUND AND HYPOTHESES

Auditory verbal hallucinations (AVH) are central features of schizophrenia (SZ). However, AVH also occur in a small percentage of the general population who do not have a need for care, termed nonclinical voice hearers (NCVH). We sought to determine the degree to which the experience of AVH was similar in NCVH and in people with schizophrenia (PSZ) and evaluate the degree to which NCVH shared other features of SZ such as delusional beliefs, cognitive impairment, and negative symptoms.

STUDY DESIGN

We recruited 76 people with a DSM-V diagnosis of SZ/schizoaffective disorder (PSZ; 49 with current AVH, 27 without), 48 NCVH, and 51 healthy controls. Participants received a broad battery of clinician-administered and self-report symptom assessments and a focused cognitive assessment.

STUDY RESULTS

The AVH of NCVH and PSZ shared very similar sensory features. NCVH experienced less distress, had greater control over their AVH, and, unlike PSZ, rarely heard 2 voices speaking to each other. NCVH demonstrated a wide range of deeply held unusual beliefs, but reported less paranoia, and fewer first-rank symptoms such as passivity and alterations in self-experience. NCVH showed no evidence of cognitive deficits or negative symptoms.

CONCLUSIONS

The AVH in NCVH and PSZ demonstrate important similarities as well as clear differences. Specific features, rather than the presence, of AVH appear to determine the need for care. NCVH do not share the cognitive and motivational deficits seen in PSZ. These results suggest that AVH and unusual beliefs can be separated from the broader phenotype of SZ.

Schneider's first-rank symptoms have neither diagnostic value for schizophrenia nor higher clinical validity than other delusions and hallucinations in psychotic disorders

The validity of studies on the diagnostic significance of first-rank symptoms (FRS) for schizophrenia has been put in doubt because of a poor compliance with Schneider's criterion for their definition and the lack of use of the phenomenological method for their assessment. In this study, using a rigorously phenomenological approach to elicit FRS, we examined (a) the degree to which unequivocally present FRS differentiated schizophrenia (n=513) from other psychotic disorders (n=633), and (b) the comparative validity between FRS and other reality-distortion symptoms against 16 external validators in the whole sample of psychotic disorders (n=1146). Diagnostic performance indices (with 95% CIs) of FRS for diagnosing schizophrenia were as follows: sensitivity=0.58 (0.54-0.61), specificity=0.65 (0.62-0.67), positive predictive value=0.57 (0.54-0.60) and negative predictive value=0.65 (0.63-0.68). While the overall association pattern of FRS and non-FRS scores with the validators was rather similar, three validators (premorbid social adjustment, number of hospitalizations and global assessment of functioning) were significantly related to non-FRS scores (p < 0.006) but not to FRS scores (p > 0.05). Furthermore, no validator was significantly related to FRS scores and unrelated to non-FRS scores, all of which indicates an overall better predictive validity for non-FRS delusions and hallucinations. These findings suggest that FRS do not have diagnostic value for diagnosing schizophrenia and that they do not meaningfully add to the external validity showed by other delusions and hallucinations. We believe that much of the misunderstanding about the diagnostic and clinical validity of FRS for schizophrenia is rooted in Schneider's confusing concept of the disorder.

Attenuated first-rank symptoms and conversion to psychosis in a clinical high-risk cohort

AIM

We sought to examine attenuated first-rank symptoms (FRS) and subcomponents of the Unusual Thought Content (P.1.) section of the Structured Interview for Psychosis-Risk Syndromes (SIPS) to investigate the robust relationship between total P.1. and conversion. We hypothesized that attenuated FRS would drive the association and, additionally, be most predictive of a schizophrenia diagnosis.

METHOD

We assessed 189 clinical high-risk participants. Two independent raters separately scored attenuated FRS and each subcomponent of P.1. as if each were the only symptom reported. Total P.1. was also scored. Participants were evaluated for conversion up to 2 years.

RESULTS

While total P.1. score significantly predicted conversion in the 54 converters, attenuated FRS, which were relatively uncommon in this sample, nor any subcomponent of P.1., was independently predictive. FRS did not predict conversion to schizophrenia among 35 subjects.

CONCLUSION

Although attenuated FRS, and subcomponents of P.1. of the SIPS, did not significantly predict transition to psychosis, our results support previous research affirming the value of total P.1. score as a tool for predicting conversion to psychosis.

Clinical, socio-demographic and psychological characteristics in individuals with persistent psychotic experiences with and without a "need for care"

Individuals reporting persistent psychotic experiences (PEs) in the general population, but without a "need for care", are a unique group of particular importance in identifying risk and protective factors for psychosis. We compared people with persistent PEs and no "need for care" (non-clinical, N=92) with patients diagnosed with a psychotic disorder (clinical, N=84) and controls without PEs (N=83), in terms of their phenomenological, socio-demographic and psychological features. The 259 participants were recruited from one urban and one rural area in the UK, as part of the UNIQUE (Unusual Experiences Enquiry) study. Results showed that the non-clinical group experienced hallucinations in all modalities as well as first-rank symptoms, with an earlier age of onset than in the clinical group. Somatic/tactile hallucinations were more frequent than in the clinical group, while commenting and conversing voices were rare. Participants in the non-clinical group were differentiated from their clinical counterparts by being less paranoid and deluded, apart from ideas of reference, and having fewer cognitive difficulties and negative symptoms. Unlike the clinical group, they were characterized neither by low psychosocial functioning nor by social adversity. However, childhood trauma featured in both groups. They were similar to the controls in psychological characteristics: they did not report current emotional problems, had intact self-esteem, displayed healthy schemas about the self and others, showed high life satisfaction and well-being, and high mindfulness. These findings support biopsychosocial models postulating that environmental and psychological factors interact with biological processes in the aetiology of psychosis. While some PEs may be more malign than others, lower levels of social and environmental adversity, combined with protective factors such as intact IQ, spirituality, and psychological and emotional well-being, may reduce the likelihood of persistent PEs leading to pathological outcomes. Future research should focus on protective factors and determinants of well-being in the context of PEs, rather than exclusively on risk factors and biomarkers of disease states.

Deficits in agency in schizophrenia, and additional deficits in body image, body schema, and internal timing, in passivity symptoms

Individuals with schizophrenia, particularly those with passivity symptoms, may not feel in control of their actions, believing them to be controlled by external agents. Cognitive operations that contribute to these symptoms may include abnormal processing in agency as well as body representations that deal with body schema and body image. However, these operations in schizophrenia are not fully understood, and the questions of general versus specific deficits in individuals with different symptom profiles remain unanswered. Using the projected-hand illusion (a digital video version of the rubber-hand illusion) with synchronous and asynchronous stroking (500 ms delay), and a hand laterality judgment task, we assessed sense of agency, body image, and body schema in 53 people with clinically stable schizophrenia (with a current, past, and no history of passivity symptoms) and 48 healthy controls. The results revealed a stable trait in schizophrenia with no difference between clinical subgroups (sense of agency) and some quantitative (specific) differences depending on the passivity symptom profile (body image and body schema). Specifically, a reduced sense of self-agency was a common feature of all clinical subgroups. However, subgroup comparisons showed that individuals with passivity symptoms (both current and past) had significantly greater deficits on tasks assessing body image and body schema, relative to the other groups. In addition, patients with current passivity symptoms failed to demonstrate the normal reduction in body illusion typically seen with a 500 ms delay in visual feedback (asynchronous condition), suggesting internal timing problems. Altogether, the results underscore self-abnormalities in schizophrenia, provide evidence for both trait abnormalities and state changes specific to passivity symptoms, and point to a role for internal timing deficits as a mechanistic explanation for external cues becoming a possible source of self-body input.

The special treatment of first rank auditory hallucinations and bizarre delusions in the diagnosis of schizophrenia

The presence of a single first-rank auditory hallucination (FRAH) or bizarre delusion (BD) is sufficient to satisfy the symptom criterion for a DSM-IV-TR diagnosis of schizophrenia. We queried two independent databases to investigate how prevalent FRAH and BD are in schizophrenia spectrum disorders and whether the diagnosis depends on them. FRAH was common in both datasets (42.2% and 55.2%) and BD was present in the majority of patients (62.5% and 69.7%). However, FRAH and BD rarely determined the diagnosis. In the first database, we found only seven cases among 325 patients (2.1%) and in the second database we found only one case among 201 patients (0.5%) who were diagnosed based on FRAH or BD alone. Among patients with FRAH, 96% had delusions, 14-42% had negative symptoms, 15-21% had disorganized or catatonic behavior, and 20-23% had disorganized speech. Among patients with BD, 88-99% had hallucinations, 17-49% had negative symptoms, 20-27% had disorganized or catatonic behavior, and 21-25% had disorganized speech. We conclude that FRAH and BD are common features of schizophrenia spectrum disorders, typically occur in the context of other psychotic symptoms, and very rarely constitute the sole symptom criterion for a DSM-IV-TR diagnosis of schizophrenia.