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1.
Schizophr Bull ; 2024 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-39241740

RESUMEN

BACKGROUND: Since the late 1990s, there has been a worldwide surge of scientific interest in the pre-psychotic phase, resulting in the introduction of several clinical tools for early detection. The predictive accuracy of these tools has been limited, motivating the need for methodological and perspectival improvements. The EASE manual supports systematic assessment of anomalous self-experience, and proposes an overall model of understanding how most psychotic experiences may be initially generated on the basis of a unifying, fundamental, pre-reflective distortion of subjectivity. STUDY DESIGN: The EASE is time-consuming, so in order to spread the use of this essential perspective of psychosis risk we selected prototypical and frequent phenomena from the EASE, combining them into SQuEASE-11. To investigate this instrument for clinical relevance, basic psychometric properties, factor structure, and relationships with gold standard instruments and the full EASE, it was administered as an interview in the STEP intervention trial (Melbourne, Australia), with 328 clinical high-risk for psychosis (CHR-P) patients. STUDY RESULTS: The SQuEASE-11 had moderate internal consistency and revealed two correlated factors. Significant relationships were observed between the SQuEASE-11 and the widely used and validated instruments CAARMS, BPRS, SANS, MADRS, DACOBS, and SOFAS. The correlation with the full EASE was very strong. CONCLUSIONS: These 11 items do not necessarily relate specifically to ipseity disturbance, but the SQuEASE-11 seems to be a clinically relevant and brief supplementary first-line interview in CHR-P subjects. It may give a qualified indication of the need for a complete EASE interview, and it may also, importantly, inform treatment planning.

2.
Artículo en Inglés | MEDLINE | ID: mdl-39212170

RESUMEN

BACKGROUND: Self-disturbance has been considered as a core symptomatology of schizophrenia and its emergence from the prodromal phase makes it a crucial target for early detection and intervention in schizophrenia. Currently, the clinical assessment of self-disturbance relies on the self-report of patients, and clinicians have no diagnostic tools in clinical practice. Identifying the neural substrate of self-disturbance would be of great clinical value by shedding light on the core dimension of schizophrenia. CASE PRESENTATION: We first introduce an adolescent patient who initially presented self-disturbance, and clinically detectable hypoperfusion in angular gyrus (AG) was observed when early psychosis was suspected. Interestingly, the hypoperfusion in AG may correspond to improvement and exacerbation of self-disturbance. This clinical observation led us to pursue the relationship between the decreased blood flow in the AG and self-disturbance. Among 15 cases with suspected early psychosis in which single photon emission computed tomography was performed to exclude organic factors, we found additional 5 cases, including one prodromal patient, showing hypoperfusion in the AG and self-disturbance with significant correlation (r = 0.79, p = 0.00025). DISCUSSION: The self-disturbance has been interpreted as a reflection of disturbance of the "Sense of Agency", the ability to attribute their action and/or thoughts to themselves. AG has been shown to play a pivotal role in the sense of agency. These cases suggest that the hypoperfusion in AG associated with the disruption in the sense of agency would be an early clinical sign of schizophrenia. Further longitudinal studies are needed to test this hypothesis.

3.
Schizophr Res ; 269: 163-173, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38820980

RESUMEN

There is a general consensus that schizophrenia (SZ) is characterized by major changes in the sense of self. Phenomenological studies suggest that these changes in the sense of self stem from a basic disturbance, hence the term 'basic self-disturbance'. While imaging studies demonstrate changes in various regions during self-focused tasks, the exact neural correlates of such basic self-disturbances remain unclear. If the self-disturbance is indeed basic and thereby underlies all other symptoms, one would expect it to be related to more global rather than local changes in the brain. Testing this hypothesis, we conducted a systematic review of fMRI studies on self in SZ. Our main findings are 1. Abnormal activity related to the self can be observed in a variety of different regions ranging from higher-order transmodal to lower-order unimodal regions, 2. These findings hold true across different tasks including self-reflection, self-referentiality, and self-agency, and 3. The global neural abnormalities related to the self in SZ correspond to all layers of the self, predominantly the mental and exteroceptive self. Such global neural disturbance of self converges well with the basic self-disturbance as described in phenomenology.


Asunto(s)
Encéfalo , Imagen por Resonancia Magnética , Esquizofrenia , Autoimagen , Humanos , Esquizofrenia/fisiopatología , Esquizofrenia/diagnóstico por imagen , Encéfalo/diagnóstico por imagen , Encéfalo/fisiopatología , Ego , Psicología del Esquizofrénico
4.
Schizophr Bull ; 50(2): 472-483, 2024 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-38069907

RESUMEN

A growing body of research supports the role of self-disorders as core phenotypic features of schizophrenia-spectrum conditions. Self-disorders comprise various alterations of conscious experience whose theoretical understanding continues to present a challenge. This is the second of two articles that aim to clarify the nature of self-disorders in schizophrenia by considering the currently most influential, phenomenological model of schizophrenia: the basic-self-disturbance or ipseity-disorder model (IDM). The previous paper (article 1) presented a state-of-the-art overview of this model and critically assessed its descriptive adequacy with respect to the clinical heterogeneity and variability of the alterations in self- and world-awareness characteristic of schizophrenia. This paper (article 2) proposes a theoretical revision by considering how hyperreflexivity might form the crucial common thread or generating factor that unifies the heterogeneous, and sometimes even contradictory features of schizophrenic self-disorders. We outline implications of our revised model (IDMrevised) for explanatory research, therapeutic practice, and our general understanding of the abnormalities in question.


Asunto(s)
Esquizofrenia , Humanos , Psicología del Esquizofrénico , Autoimagen
5.
Schizophr Bull ; 50(2): 460-471, 2024 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-38069912

RESUMEN

A growing body of research supports the role of self-disorders as core phenotypic features of schizophrenia-spectrum disorders. Self-disorders comprise various alterations of conscious experience whose theoretical understanding continues to present a challenge. The following 2 articles aim to provide further clarification of the nature of self-disorders in schizophrenia by offering a comprehensive review (article 1) and theoretical revision (article 2) of the currently most influential model of altered selfhood in schizophrenia: the basic-self-disturbance or ipseity-disorder model (IDM). This article presents a state-of-the-art overview of the current self-disturbance model and critically assesses its descriptive adequacy with respect to the clinical variability and heterogeneity of the alterations in self- and world-awareness characteristic of schizophrenia. Special attention is paid to experiences of exaggerated basic self, increased "grip" or "hold" on the world, and paradoxical combinations. The next article proposes a theoretical revision of the self-disturbance model by considering how hyperreflexivity might form the crucial common thread or generating factor that unifies the phenomenologically heterogeneous, and sometimes even contradictory features of schizophrenic self-disorders. We outline the implications of our revised model for explanatory research, therapeutic practice, and our general understanding of the abnormalities in question.


Asunto(s)
Esquizofrenia , Humanos , Psicología del Esquizofrénico , Autoimagen
6.
Early Interv Psychiatry ; 18(2): 153-164, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37394278

RESUMEN

AIM: Basic self disturbance is a putative core vulnerability marker of schizophrenia spectrum disorders. The primary aims of the Self, Neuroscience and Psychosis (SNAP) study are to: (1) empirically test a previously described neurophenomenological self-disturbance model of psychosis by examining the relationship between specific clinical, neurocognitive, and neurophysiological variables in UHR patients, and (2) develop a prediction model using these neurophenomenological disturbances for persistence or deterioration of UHR symptoms at 12-month follow-up. METHODS: SNAP is a longitudinal observational study. Participants include 400 UHR individuals, 100 clinical controls with no attenuated psychotic symptoms, and 50 healthy controls. All participants complete baseline clinical and neurocognitive assessments and electroencephalography. The UHR sample are followed up for a total of 24 months, with clinical assessment completed every 6 months. RESULTS: This paper presents the protocol of the SNAP study, including background rationale, aims and hypotheses, design, and assessment procedures. CONCLUSIONS: The SNAP study will test whether neurophenomenological disturbances associated with basic self-disturbance predict persistence or intensification of UHR symptomatology over a 2-year follow up period, and how specific these disturbances are to a clinical population with attenuated psychotic symptoms. This may ultimately inform clinical care and pathoaetiological models of psychosis.


Asunto(s)
Trastornos Psicóticos , Esquizofrenia , Humanos , Factores de Riesgo , Trastornos Psicóticos/psicología , Esquizofrenia/diagnóstico , Estudios Longitudinales , Atención , Escalas de Valoración Psiquiátrica
7.
Artículo en Inglés | MEDLINE | ID: mdl-37414359

RESUMEN

BACKGROUND: Basic self-disturbance, or anomalous self-experiences (ASEs), is a core feature of the schizophrenia spectrum. We propose a novel method of natural language processing to quantify ASEs in spoken language by direct comparison to an inventory of self-disturbance, the Inventory of Psychotic-Like Anomalous Self-Experiences (IPASE). We hypothesized that there would be increased similarity in open-ended speech to the IPASE items in individuals with early-course psychosis (PSY) compared with healthy individuals, with clinical high-risk (CHR) individuals intermediate in similarity. METHODS: Open-ended interviews were obtained from 170 healthy control participants, 167 CHR participants, and 89 PSY participants. We calculated the semantic similarity between IPASE items and "I" sentences from transcribed speech samples using S-BERT (Sentence Bidirectional Encoder Representation from Text). Kolmogorov-Smirnov tests were used to compare distributions across groups. A nonnegative matrix factorization of cosine similarity was performed to rank IPASE items. RESULTS: Spoken language of CHR individuals had the greatest semantic similarity to IPASE items when compared to both healthy control (s = 0.44, p < 10-14) and PSY (s = 0.36, p < 10-6) individuals, while IPASE scores were higher among PSY than CHR group participants. In addition, the nonnegative matrix factorization approach produced a data-driven domain that differentiated the CHR group from the others. CONCLUSIONS: We found that open-ended interviews elicited language with increased semantic similarity to the IPASE by participants in the CHR group compared with patients with psychosis. This demonstrates the utility of these methods for differentiating patients from healthy control participants. This complementary approach has the capacity to scale to large studies investigating phenomenological features of schizophrenia and potentially other clinical populations.


Asunto(s)
Trastornos Psicóticos , Esquizofrenia , Humanos , Habla , Procesamiento de Lenguaje Natural
8.
Front Psychol ; 14: 1124859, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36923145

RESUMEN

Introduction: Basic self-disorders (SDs) and neurocognitive impairments are fundamental trait-like aspects of schizophrenia spectrum disorders. There has been little research on the association between SDs and neurocognitive impairments in schizophrenia, and no longitudinal studies have investigated if they are related. The aim of this study was to investigate the association between SDs and neurocognitive function in a follow-up study of patients with schizophrenia. Methods: SDs and neurocognition were examined in 35 patients with schizophrenia during their first treatment and 7 years later (mean 7.1, SD 0.42). SDs were examined with the Examination of Anomalous Self-Experience (EASE) instrument. The neurocognitive examination included assessments of psychomotor speed, executive- and memory functions. Results: Poorer executive functions at baseline were significantly associated with more SDs 7 years later and smaller reductions in SDs over time. There were no significant associations between other neurocognitive functions and SDs. Discussion: Executive functions are important for self-regulation, and impairments in these functions in everyday life may have an impact on the development and/or persistence of SDs.

9.
Psychopathology ; 56(5): 359-370, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36754040

RESUMEN

INTRODUCTION: The experience of "sensed presence" or "felt presence" in the absence of "other" has been described as a complex multimodal experience to which meaning is given. Sensed presence (SenP) is a transdiagnostic experience that exists along a continuum that can appear during isolation, spirit quests, exposure to extreme elements, bereavement, anxiety, and psychosis. Given the prevalence and vast heterogeneity of SenP, in addition to a surprising lack of targeted research into this phenomenon, this research examined the interrelationship of SenP, attenuated psychosis symptoms (APS), and transliminality. Transliminality is composed of absorption, fantasy proneness, paranormal belief, mystical experiences, increased creativity, and hyperaesthesia. METHODS: A completely anonymous online survey of unusual experiences and mental health was distributed via social media (i.e., Twitter, Facebook, Reddit, and mass emailing lists) to recruit participants. Demographic data were analyzed using χ2 tests and one-way ANOVAs. A two-step cluster analysis was conducted to identify distinct sub-categories of transliminality followed by ANOVAs with bootstrapping at 1,000 iterations to compare SenP, increased APS, and transliminality. Pearson's bivariate correlations were conducted to determine the association between SenP, APS, and transliminality. RESULTS: Together with descriptive findings, we show distinct characteristics between clusters. T1 cluster consisted of individuals with few SenP experiences, low APS, and low transliminality. T2 consisted of individuals with a moderate prevalence of SenP, low APS, moderate transliminality, and increased overall feeling of closeness to G-d. There was no significant difference in APS between T1 and T2 or in the level of distress associated with APS. T3 individuals showed a significantly higher prevalence of SenP in all domains (frequency, distress, vividness, and total score), higher APS, and higher transliminality, compared to T1 and T2. The T3 cluster met criteria for high risk to develop psychosis. CONCLUSION: Thus, our findings demonstrate a strong association and entanglement of these experiences which suggests that the interrelatedness of transliminality/absorption and APS may serve as a potentially provocative underlying structure in the phenomenology of SenP.


Asunto(s)
Estado de Conciencia , Trastornos Psicóticos , Humanos , Trastornos Psicóticos/diagnóstico
10.
EClinicalMedicine ; 55: 101733, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36386038

RESUMEN

Background: Language impairments are key features of schizophrenia spectrum disorders, and have also been suggested to signal enhanced psychosis risk. Incoherence, derailment, and monotonous speaking are however closely related to psychosis onset, and thus not very early markers. Recent phenomenologic-psychiatric studies claim that basic self-disturbance (BSD) may represent more useful early markers. Methods: We searched for distinctive irregular linguistics of 30 CHR outpatient adolescents, aged 12-18 years. Standard instruments established psychosis risk and BSD. Participants chose three personal and well manifested BSD phenomena. Ninety verbatim statements were analyzed and grouped into higher order clusters of linguistic irregularities. Findings: We identified five clusters of irregular language features: distinctive words, describing an atmosphere of unreality; irregular use of prepositions, indicating experiential detachment; shifts of personal pronouns, indicating identity confusion; near-literal use of metaphors and conjunctions indicating existential insecurity, and idiosyncratic use of adjectives indicating perceptual transcendence. Interpretation: The adolescents provided naturalistic descriptions of experiences that were markedly twisted and almost ineffable. This unique irregular "BSD -language" was highly meaningful in its proper context, expressing informative characteristics of first-personal experiential alterations, essential for early detection. The features may additionally represent precursors of psychosis transition, useful for clinical decision-making. Funding: Foundation Dam, Oslo, Norway (Grant Number 2017/FO143368).

11.
Schizophr Bull ; 49(2): 444-453, 2023 03 15.
Artículo en Inglés | MEDLINE | ID: mdl-36184074

RESUMEN

BACKGROUND AND HYPOTHESIS: Disturbances in self-experience are a central feature of schizophrenia and its study can enhance phenomenological understanding and inform mechanisms underlying clinical symptoms. Self-experience involves the sense of self-presence, of being the subject of one's own experiences and agent of one's own actions, and of being distinct from others. Self-experience is traditionally assessed by manual rating of interviews; however, natural language processing (NLP) offers automated approach that can augment manual ratings by rapid and reliable analysis of text. STUDY DESIGN: We elicited autobiographical narratives from 167 patients with schizophrenia or schizoaffective disorder (SZ) and 90 healthy controls (HC), amounting to 490 000 words and 26 000 sentences. We used NLP techniques to examine transcripts for language related to self-experience, machine learning to validate group differences in language, and canonical correlation analysis to examine the relationship between language and symptoms. STUDY RESULTS: Topics related to self-experience and agency emerged as significantly more expressed in SZ than HC (P < 10-13) and were decoupled from similarly emerging features such as emotional tone, semantic coherence, and concepts related to burden. Further validation on hold-out data showed that a classifier trained on these features achieved patient-control discrimination with AUC = 0.80 (P < 10-5). Canonical correlation analysis revealed significant relationships between self-experience and agency language features and clinical symptoms. CONCLUSIONS: Notably, the self-experience and agency topics emerged without any explicit probing by the interviewer and can be algorithmically detected even though they involve higher-order metacognitive processes. These findings illustrate the utility of NLP methods to examine phenomenological aspects of schizophrenia.


Asunto(s)
Metacognición , Trastornos Psicóticos , Esquizofrenia , Humanos , Semántica , Procesamiento de Lenguaje Natural
13.
Eur Arch Psychiatry Clin Neurosci ; 272(6): 1007-1019, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34783878

RESUMEN

Basic self-disturbance (BSD) has been proposed as a driver of symptom development in schizophrenia spectrum disorders (SSDs). In a one-year follow-up of 32 patients (15-30 years) at putative risk for psychosis, we investigated trajectories of BSD levels from baseline to follow-up, and associations between clinical characteristics at baseline and follow-up, including follow-up levels of BSD (assessed with the EASE). Clinical high risk (CHR) for psychosis status and symptom severity were assessed with the SIPS/SOPS scales and also according to the cognitive basic symptoms high-risk criteria (COGDIS). DSM-IV diagnoses, functioning and other clinical characteristics were assessed with standard clinical instruments. Higher severity of negative symptoms and meeting COGDIS criteria at baseline were associated with higher BSD levels at follow-up. All measured at follow-up, higher BSD levels correlated with higher severity of positive, negative, disorganization and general symptoms, and with a lower level of global functioning. We found higher BSD levels at follow-up in subjects with schizotypal personality disorder (SPD) at baseline (n = 5) and in SSDs at follow-up (n = 12, including nine with SPD). Mean BSD levels decreased significantly from baseline to follow-up, but individual trajectories varied considerably. Increased BSD levels were associated with higher baseline BSD levels, non-remission of positive symptoms and functional decline. Overall, the current study indicates that subgroups in the CHR population with a higher risk of non-remission or deterioration may be identified by supplementing CHR criteria with assessment of BSD and negative symptoms.


Asunto(s)
Trastornos Psicóticos , Esquizofrenia , Trastorno de la Personalidad Esquizotípica , Estudios de Seguimiento , Humanos , Síntomas Prodrómicos , Trastornos Psicóticos/epidemiología , Factores de Riesgo , Trastorno de la Personalidad Esquizotípica/diagnóstico
14.
Early Interv Psychiatry ; 16(1): 26-33, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-33559381

RESUMEN

AIM: Phenomenological researchers argue that schizophrenia spectrum disorders are primarily disorders of the basic self. To test this argument, we compared self-report and lexical measures of basic self-disturbance between schizophrenia spectrum (high-schizotypy) and non-spectrum groups (low-schizotypy). METHODS: From an initial sample (n = 310) screened with the (SPQ), n = 39 were classified as high schizotypy (z > 1.28 on at least one SPQ factor scale) and were compared to a randomly selected low-schizotypy group (z < 1 on all three SPQ factor scales; n = 41). Participants wrote four narratives about personal and fictional experiences and completed the Ego Strength Questionnaire and a self-report version of the Schizophrenia Proneness Instrument. The written narratives were subjected to linguistic inquiry to examine pronoun usage (lexical measures). RESULTS: The high-schizotypy group reported higher levels of basic symptoms, lower ego strength, and used third-person and personal pronouns more frequently than the low-schizotypy group. Self-report measures correlated significantly with lexical measures. Self-report and lexical measures were useful tools in predicting high schizotypy, correctly classifying 68% and 69% of schizotypy and non-schizotypy, respectively. CONCLUSION: In line with phenomenologists' arguments, high schizotypy was associated, to some extent, with basic self-disturbance.


Asunto(s)
Esquizofrenia , Trastorno de la Personalidad Esquizotípica , Humanos , Esquizofrenia/diagnóstico , Trastorno de la Personalidad Esquizotípica/diagnóstico , Autoinforme , Encuestas y Cuestionarios
15.
J Clin Med ; 10(18)2021 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-34575237

RESUMEN

Cognitive biases are an important factor contributing to the development and symptom severity of psychosis. Despite the fact that various cognitive biases are contributing to psychosis, they are rarely investigated together. In the current systematic review, we aimed at investigating specific and shared functional neural correlates of two important cognitive biases: aberrant salience and source monitoring. We conducted a systematic search of fMRI studies of said cognitive biases. Eight studies on aberrant salience and eleven studies on source monitoring were included in the review. We critically discussed behavioural and neuroimaging findings concerning cognitive biases. Various brain regions are associated with aberrant salience and source monitoring in individuals with schizophrenia and the risk of psychosis. The ventral striatum and insula contribute to aberrant salience. The medial prefrontal cortex, superior and middle temporal gyrus contribute to source monitoring. The anterior cingulate cortex and hippocampus contribute to both cognitive biases, constituting a neural overlap. Our review indicates that aberrant salience and source monitoring may share neural mechanisms, suggesting their joint role in producing disrupted external attributions of perceptual and cognitive experiences, thus elucidating their role in positive symptoms of psychosis. Account bridging mechanisms of these two biases is discussed. Further studies are warranted.

16.
J Psychiatr Res ; 143: 144-154, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34487991

RESUMEN

The bodily self is key to emotional embodiment, which is important for social functioning and emotion regulation. There is a paucity of research systematically assessing how basic and bodily self-disturbances relate to multimodal hallucinations. This study hypothesised that participants with greater hallucination-proneness would report greater degrees of basic and bodily self-disturbance and would demonstrate more ambiguous and less discrete mapping of emotional embodiment. Stage one screened non-clinical participants' degree of hallucination-proneness. Stage two participants completed seven further questionnaires. Hierarchical linear regression modelled the influence of hallucination-proneness and covariates on measures of basic and bodily self-disturbance and sensed presence. Stage two participants also completed a computerised body mapping task (EmBODY) which assessed emotional embodiment. Topographical maps were generated to compare patterns of embodiment between high and low hallucination-proneness groups. 55 respondents participated in stage two, with 18 participants from the high or low hallucination-proneness groups completing EmBODY. In the hierarchical regression analyses, the addition of a measure of hallucination proneness in the final step only increased predictive power where the dependent variable assessed sensed presence (p = 0.035 and p = 0.009, respectively). The EmBODY data revealed that participants with low hallucination-proneness consistently reported more bodily activation across 14 emotional states, whereas the high hallucination-proneness group reported more deactivation. In conclusion, hallucination-proneness was most strongly associated with sensed presence experiences. Patterns of embodiment appeared similar between the two groups, despite consistent differences in activation and deactivation. These findings are exploratory and need to be confirmed in a larger sample.


Asunto(s)
Emociones , Alucinaciones , Estudios Transversales , Humanos , Encuestas y Cuestionarios
17.
Clin Psychol Rev ; 88: 102067, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34274799

RESUMEN

Individuals with schizophrenia-spectrum disorders face profound challenges as they attempt to maintain identity through the course of illness. Narrative identity-the study of internalized, evolving life stories-provides a rich theoretical and empirical perspective on these challenges. Based on evidence from a systematic review of narrative identity in the psychosis spectrum (30 studies, combined N = 3859), we argue that the narrative identities of individuals with schizophrenia-spectrum disorders are distinguished by three features: disjointed structure, a focus on suffering, and detached narration. Psychotic disorders typically begin to emerge during adolescence and emerging adulthood, which are formative developmental stages for narrative identity, so it is particularly informative to understand identity disturbances from a developmental perspective. We propose a developmental model in which a focus on suffering emerges in childhood; disjointed structure emerges in middle and late adolescence; and detached narration emerges before or around the time of a first psychotic episode. Further research with imminent risk and early course psychosis populations would be needed to test these predictions. The disrupted life stories of individuals on the psychosis spectrum provide multiple rich avenues for further research to understand narrative self-disturbances.


Asunto(s)
Trastornos Psicóticos , Esquizofrenia , Adulto , Humanos , Narración
18.
Front Psychiatry ; 12: 642469, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33912085

RESUMEN

Background: Interest in disordered sense of self in schizophrenia has recently re-emerged in the literature. It has been proposed that there is a basic self disturbance, underlying the diagnostic symptoms of schizophrenia, in which the person's sense of being a bounded individual continuous through time loses stability. This disturbance has been documented phenomenologically and at the level of cognitive tasks. However, the neural correlates of basic self disorder in schizophrenia are poorly understood. Methods: A search of PubMed was used to identify studies on self and schizophrenia that reported EEG or MEG data. Results: Thirty-three studies were identified, 32 using EEG and one using MEG. Their operationalizations of the self were divided into six paradigms: self-monitoring for errors, proprioception, self-other integration, self-referential processing, aberrant salience, and source monitoring. Participants with schizophrenia were less accurate on self-referential processing tasks and had slower response times across most studies. Event-related potential amplitudes differed across many early and late components, with reduced N100 suppression in source monitoring paradigms being the most replicated finding. Several studies found differences in one or more frequency band, but no coherent overall finding emerged in this area. Various other measures of brain dynamics also showed differences in single studies. Only some of the study designs were adequate to establish a causal relationship between the self and EEG or MEG measures. Conclusion: The broad range of changes suggests a global self disturbance at the neuronal level, possibly carried over from the resting state. Further studies that successfully isolate self-related effects are warranted to better understand the temporal-dynamic and spatial-topographic basis of self disorder and its relationship to basic self disturbance on the phenomenological level.

19.
Schizophr Bull ; 47(4): 927-937, 2021 07 08.
Artículo en Inglés | MEDLINE | ID: mdl-33844019

RESUMEN

Self-disturbances such as an anomalous perception of one's own body boundary are central to the phenomenology of schizophrenia (SZ), but measuring the spatial parameters of the hypothesized self-other boundary has proved to be challenging. Peripersonal space (PPS) refers to the immediate zone surrounding the body where the self interacts physically with the environment; the space that corresponds to hypothesized self-other boundary. PPS is represented by enhanced multisensory integration and faster reaction time (RT) for objects near the body. Thus, multisensory RT tasks can be used to estimate self-other boundary. We aimed to quantify PPS in SZ using an immersive virtual reality visuotactile RT paradigm. Twenty-four participants with SZ and 24 demographically matched controls (CO) were asked to detect tactile vibration while watching a ball approaching them, thrown by either a machine (nonsocial condition) or an avatar (social condition). Parameters of PPS were estimated from the midpoint of the spatial range where the tactile RT decreased most rapidly (size) and the gradient of the RT change at this midpoint (slope). Overall, PPS was smaller in participants with SZ compared with CO. PPS slope for participants with SZ was shallower than CO in the social but not in nonsocial condition, indicating an increased uncertainty of self-other boundary across an extended zone in SZ. Social condition also increased false alarms for tactile detection in SZ. Clinical symptoms were not clearly associated with PPS parameters. These findings suggest the context-dependent nature of weakened body boundary in SZ and underscore the importance of reconciliating objective and subjective aspects of self-disturbances.


Asunto(s)
Imagen Corporal/psicología , Espacio Personal , Psicología del Esquizofrénico , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Realidad Virtual
20.
Schizophr Res ; 228: 19-28, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33434729

RESUMEN

INTRODUCTION: The distinction between the schizophrenia spectrum and other types of disorders may be clinically relevant in terms of its predictive validity as suggested by studies showing schizophrenia spectrum patients have more unfavourable outcomes compared to other psychotic disorders. The present study aimed to investigate whether basic self-disturbances and neurocognitive processes that have been linked to psychosis risk have discriminative power for schizophrenia spectrum disorders in patients presenting with first episode psychosis (FEP) and at ultra-high risk for psychosis (UHR). METHODS: 38 FEP patients, 48 UHR patients, and 33 healthy controls were assessed for basic self-disturbances (using the Examination of Anomalous Self-Experience, EASE, interview), source monitoring and aberrant salience (behavioural tasks to measure neurocognitive constructs). Clinical groups were divided into patients with schizophrenia spectrum disorders and those with other non-spectrum disorders and were further compared on measures controlling for symptom severity and age. RESULTS: Basic self-disturbances distinguished schizophrenia spectrum from non-spectrum disorders in the 'FEP only' sample, F = 19.76, p < 0.001, η2partial = 0.37, and also in the combined UHR/FEP sample, F = 23.56, p < 0.001, η2partial = 0.22. Additionally, some processes related to source monitoring deficits were elevated in schizophrenia spectrum disorders. In contrast, the two groups (schizophrenia spectrum vs other diagnoses) performed similarly in aberrant salience tasks. Comparable results were obtained for analyses performed with an FEP/UHR combined sample and the 'FEP only' sample. DISCUSSION: Basic self-disturbances at the phenomenological level and source monitoring deficits on the neurocognitive level may be useful in identifying risk of schizophrenia spectrum disorders at the earliest clinical presentation.


Asunto(s)
Trastornos Psicóticos , Esquizofrenia , Humanos , Trastornos Psicóticos/complicaciones , Trastornos Psicóticos/diagnóstico , Trastornos Psicóticos/epidemiología , Esquizofrenia/complicaciones , Esquizofrenia/diagnóstico , Esquizofrenia/epidemiología , Psicología del Esquizofrénico
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