Quantifying the Core Deficit in Classical Schizophrenia

Abstract

<jats:title>Abstract</jats:title> <jats:p>In the classical descriptions of schizophrenia, Kraepelin and Bleuler recognized disorganization and impoverishment of mental activity as fundamental symptoms. Their classical descriptions also included a tendency to persisting disability. The psychopathological processes underlying persisting disability in schizophrenia remain poorly understood. The delineation of a core deficit underlying persisting disability would be of value in predicting outcome and enhancing treatment. We tested the hypothesis that mental disorganization and impoverishment are associated with persisting impairments of cognition and role function, and together reflect a latent core deficit that is discernible in cases diagnosed by modern criteria. We used Confirmatory Factor Analysis to determine whether measures of disorganization, mental impoverishment, impaired cognition, and role functioning in 40 patients with schizophrenia represent a single latent variable. Disorganization scores were computed from the variance shared between disorganization measures from 3 commonly used symptom scales. Mental impoverishment scores were computed similarly. A single factor model exhibited a good fit, supporting the hypothesis that these measures reflect a core deficit. Persisting brain disorders are associated with a reduction in post-movement beta rebound (PMBR), the characteristic increase in electrophysiological beta amplitude that follows a motor response. Patients had significantly reduced PMBR compared with healthy controls. PMBR was negatively correlated with core deficit score. While the symptoms constituting impoverished and disorganized mental activity are dissociable in schizophrenia, nonetheless, the variance that these 2 symptom domains share with impaired cognition and role function, appears to reflect a pathophysiological process that might be described as the core deficit of classical schizophrenia.</jats:p>

Regional Brain Correlates of Beta Bursts in Health and Psychosis: A Concurrent Electroencephalography and Functional Magnetic Resonance Imaging Study

“…An alternative hypothesis is that abnormalities in the mechanisms by which beta bursts coordinate reactivation of contextually appropriate content can manifest as disorganization, working memory deficits ( 53 ), and inaccurate forward models ( 56 ). Under stress, these may lead to a surfeit of dopamine-mediated error signals that precipitate the dopamine dysregulation of acute psychosis as well as reflect the core deficit ( 5 , 11 ) associated with persisting impairment.…”

“…Typically, beta amplitude rebounds to above-baseline levels following a motor response, termed post-movement beta rebound (PMBR). Previously, we found that in patients with schizophrenia recruited in a stable state of their illness, PMBR was attenuated compared with control subjects, with greater attenuation in those with more severe disorganization symptoms and greater impairment of cognitive and role function ( 2 , 5 ). In healthy control participants, we found that PMBR attenuation was associated with higher schizotypal personality scores, most strongly with subscale scores on a factor reflecting subclinical disorganization traits ( 7 ), suggesting that this association is not an artifact of medication.…”

“…Emerging evidence indicates that beta oscillations are abnormal in a range of neuropsychiatric conditions, including schizophrenia ( 1 , 2 , 3 , 4 , 5 , 6 ). Typically, beta amplitude rebounds to above-baseline levels following a motor response, termed post-movement beta rebound (PMBR).…”

“…In psychosis, disorganization is predictive of persisting illness and impairments of cognition and role function ( 8 , 9 , 10 , 11 ) and has been proposed as a marker for a core deficit in psychosis ( 5 , 11 ). Understanding the nature of PMBR and of its attenuation in psychosis therefore may illuminate the mechanisms underlying persisting illness.…”

Imprecise Predictive Coding Is at the Core of Classical Schizophrenia

“… Rathnaiah et al (2020) demonstrated that the severity of classical schizophrenia can be estimated using symptom scores assessed using the Positive and Negative Symptom Scale (PANSS) ( Kay et al, 1987 ); the Comprehensive Assessment of Symptoms and History (CASH) ( Andreasen et al, 1992 ); or Symptoms and Signs of Psychotic Illness (SSPI) ( Liddle et al, 2002 ).…”