Self-concept, emotion and memory performance in schizophrenia

Impact of minimal self disorders on naturalistic episodic memory in first-episode psychosis and parallels in healthy individuals with schizotypal traits

Background

Self-disorders constitute a core feature of the schizophrenia spectrum, including early stages such as first-episode psychosis (FEP). These disorders impact the minimal Self, or bodily self-consciousness, which refers to the basic, pre-reflective sense of embodied experience. The minimal Self is intrinsically linked to episodic memory, which captures specific past experiences of the Self. However, research on this relationship in the schizophrenia spectrum remains scarce. This pilot study aimed to investigate how the minimal Self modulated episodic memory of naturalistic events in FEP, using immersive virtual reality. A secondary objective was to examine the relationships between sense of Self, embodiment, episodic memory, schizotypal personality traits in healthy participants (CTL), and psychopathology in FEP.

Methods

A full-body illusion was induced in 10 FEP and 35 matched CTL, using a first-person avatar, with synchronous or asynchronous visuomotor stimulation (strong or weak embodiment conditions, respectively). Following embodiment induction, participants navigated a virtual city and encountered naturalistic daily life events, which were incidentally encoded. Episodic memory of these events was assessed through a comprehensive recognition task (factual and contextual information, retrieval phenomenology). Sense of Self, schizotypal personality traits, and psychopathology were assessed via self-reported questionnaires or clinical assessments.

Results

Synchronous visuomotor stimulation successfully induced a stronger sense of embodiment in both FEP and CTL. The strong embodiment condition was associated with reduced perceived virtual space occupation by the body in FEP. Under strong embodiment, FEP performed significantly worse than CTL in contextual information recognition, but their ratings for retrieval phenomenology were comparable to CTL. Conversely, under weak embodiment, FEP performed similarly to CTL in contextual information recognition, but they rated retrieval phenomenology significantly lower. For CTL, we observed a slight, though non-significant, enhancement in recognition memory under strong compared to weak embodiment. Additionally, higher schizotypy in CTL correlated with a diminished sense of Self and poorer episodic memory.

Conclusions

Disturbances in the minimal Self in FEP are associated with episodic memory impairments. These findings emphasise the importance of targeting minimal Self-disorders in schizophrenia spectrum disorders, since episodic memory impairments may negatively affect patients' quality of life and psychosocial outcomes. Additionally, they support a fully dimensional model of schizotypy.

Disturbance at the self-other boundary in schizophrenia: Linking phenomenology to clinical neuroscience

In this selective review, we describe the current neuroscientific literature on disturbances of the self-other boundary in schizophrenia as they relate to structural and experiential aspects of the self. Within these two broad categories, the structural self includes body ownership and agency, and the experiential self includes self-reflection, source monitoring, and self-referential and autobiographical memory. Further, we consider how disturbances in these domains link to the phenomenology of schizophrenia. We identify faulty internal predictive coding as a potential mechanism of disturbance in body ownership and agency, which results in susceptibility to bias (over- or under-attributing outcomes to one's own actions or intentions). This is reflected in reduced activity in the temporoparietal junction (TPJ), a heteromodal association area implicated in several aspects of self-other processing, as well as reduced fronto-parietal functional connectivity. Deficits of the experiential self in schizophrenia may stem from a lack of salience of self-related information, whereby the mental representation of self is not as rich as in healthy controls and therefore does not result in the same level of privileged processing. As a result, memory for self-referential material and autobiographical memory processes is impaired, which hinders creation of a cohesive life narrative. Impairments of the experiential self implicate abnormal activation patterns along the cortical midline, including medial prefrontal cortex and posterior cingulate/precuneus, as well as TPJ. In fact, TPJ appears to be involved in all the reviewed aspects of the self-other disturbance. We conclude with suggestions for future work, including implications for interventions with critical timing considerations.

Self-Processing and Self-Face Reaction Time Latencies: A Review

In this article, we detail the advantages of self-face identification latencies over more traditional tests of mirror self-recognition. Using reaction time latencies (measured in milliseconds) to identify different dimensions of the self, instead of relying on a simple dichotomous pass/fail mirror mark-test outcome, enables investigators to examine individual differences in self-processing time. This is a significant methodological step forward with important implications. The point of departure for our article is to detail research we and others have conducted on latencies for self-face identification, to show how self-processing occurs in the right side of the brain, how schizophrenia is a self-processing disorder, how self-face reaction time latencies implicate the existence of an underlying multiple modal self-processing system, and to explore ideas for future research.

Resting-state functional EEG connectivity in salience and default mode networks and their relationship to dissociative symptoms during NMDA receptor antagonism

N-methyl-d-aspartate receptor (NMDAR) antagonists administered to healthy humans results in schizophrenia-like symptoms, which are thought in part to be related to glutamatergically altered electrophysiological connectivity in large-scale intrinsic functional brain networks. Here, we examine resting-state source electroencephalographic (EEG) connectivity within and between the default mode (DMN: for self-related cognitive activity) and salience networks (SN: for detection of salient stimuli in internal and external environments) in 21 healthy volunteers administered a subanesthetic dose of the dissociative anesthetic and NMDAR antagonist, ketamine. In addition to provoking symptoms of dissociation, which are thought to originate from an altered sense of self that is common to schizophrenia, ketamine induces frequency-dependent increases and decreases in connectivity within and between DMN and SN. These altered interactive network couplings together with emergent dissociative symptoms tentatively support an NMDAR-hypofunction hypothesis of disturbed electrophysiologic connectivity in schizophrenia.

Altered neural basis of self-reflective processing in schizophrenia: An fMRI study

BACKGROUND

Impaired self-awareness has often been described in schizophrenia. Recent neuroimaging studies examining the self-reflection processes in schizophrenia have produced inconsistent results.

METHOD

We examined the self-reflective neural network using self- and other-evaluation tasks in schizophrenia. Fifteen schizophrenia patients and fifteen age- and sex-matched healthy subjects underwent functional magnetic resonance imaging. Subjects were required to decide whether the sentence described their own personal trait (self-evaluation) and that of their close friends (other-evaluation).

RESULTS

Unlike normal control subjects, the schizophrenia patients did not have greater activation of the left posterior cingulate gyrus and hippocampus during self-evaluation than during other-evaluation. On the other hand, the schizophrenia patients had higher activation of the right superior frontal and right supramarginal gyri during self-evaluation than control subjects. Only the patient group exhibited hyperactivation in the left hippocampus and right external capsule associated with the other-evaluation task.

CONCLUSIONS

These findings provide evidence for an altered neural basis of self-reflective processing, which may underlie the self-awareness deficits in schizophrenia.

The impact of internalized stigma on the well-being of people with Schizophrenia

Previous research has shown that the internalization of schizophrenia-related stigma is associated with a worse prognosis and more suicidal tendencies. Empirical literature suggests that affective well-being -composed of positive affect (e.g. pride, enthusiasm, vitality, inspiration) and negative affect (e.g. shame, guilt, annoyance, worry)- seems to be the key component which, when being negatively affected by internalized stigma and the subsequent deterioration of self-concept, would lead to more severe symptomatology, lower recovery, and higher risk of suicide. Thus, our aim was to delve into the process by which affective well-being is impacted by the two main dimensions of internalized stigma (stereotype endorsement and alienation), with self-esteem and self-efficacy as mediators. The model was tested by path analysis -maximum likelihood procedure- in a sample of 216 patients. Our results indicate that alienation would entail more damage than stereotype endorsement both on affective well-being and on self-concept. Findings suggest that self-esteem mediates the impact of both internalized stigma dimensions on both types of affect, and that self-efficacy mediates the impact of alienation on positive affect. It is concluded that, in clinical practice, an important effort should be made to prevent internalized stigma (especially, alienation) and to promote positive self-concept of patients (especially, self-esteem).

The neural correlates of self-referential memory encoding and retrieval in schizophrenia

BACKGROUND

Enhanced memory for self-oriented information is known as the self-referential memory (SRM) effect. fMRI studies of the SRM effect have focused almost exclusively on encoding, revealing selective engagement of the medial prefrontal cortex (mPFC) during "self" relative to other processing conditions. Other critical areas for self-processing include ventrolateral prefrontal cortex (vlPFC), temporo-parietal junction (TPJ) and posterior cingulate/precuneus (PCC/PC). Previous behavioral studies show that individuals with schizophrenia fail to benefit from this memory boost. However, the neural correlates of this deficit, at either encoding or retrieval, are unknown.

METHODS

Twenty individuals with schizophrenia and 16 healthy controls completed an event-related fMRI SRM paradigm. During encoding, trait adjectives were judged in terms of structural features ("case" condition), social desirability ("other" condition), or as self-referential ("self" condition). Participants then completed an unexpected recognition test (retrieval phase). We examined BOLD activation during both encoding and retrieval within mPFC, vlPFC, TPJ, and PCC/PC regions-of-interest (ROIs).

RESULTS

During encoding, fMRI data indicated both groups had greater activation during the "self" relative to the "other" condition across ROIs. Controls showed this primarily in mPFC whereas patients showed this in PCC/PC. During retrieval, fMRI data indicated controls showed differentiation across ROIs between "self" and "other" conditions, but patients did not.

CONCLUSIONS

Results suggest regional differences in the neural processing of self-referential information in individuals with schizophrenia, perhaps because representation of the self is not as well established in patients relative to controls. The current study presents novel findings that add to the literature implicating impaired self-oriented processing in schizophrenia.

Investigating the link between drug-naive first episode psychoses (FEPs), weight gain abnormalities and brain structural damages: Relevance and implications for therapy

Evidence suggests that obesity and overweight may be associated with severe brain structural abnormalities and poor cognitive and functional outcomes in the general population. Despite these observations and the high prevalence of weight gain abnormalities in patients with psychosis spectrum disorders (PSDs), no studies have investigated the impact that these metabolic disturbances may have on brain structures and development in the earliest stages of PSDs. In the present review we shed light on the association between weight gain and brain structural abnormalities that may affect the course of illness in drug-naïve FEPs. Given the lack of studies directly investigating this issue, we firstly identified and critically evaluated the literature assessing weight gain abnormalities and gray or white matter (GM, WM) volumes (either globally or in specific regions of interest) in otherwise healthy obese/overweight adolescents and young adults. We then compared the results of this systematic review with those of two recent meta-analysis investigating GM and WM abnormalities in drug-naïve FEPs. Weight gain in otherwise healthy subjects was consistently associated with frontal and temporal GM atrophy and with reduced integrity of WM in the corpus callosum. Of relevance, all these brain regions are affected in drug-naïve FEPs, and their integrity is associated with clinical, cognitive and functional outcomes. The underlying mechanisms that may explain the association between weight gain, adiposity, and brain damage in both healthy subjects and drug-naïve FEPs are widely discussed. On the basis of this knowledge, we tried: a) to deduce an integrative model for the development of obesity in psychosis spectrum disorders; b) to identify the key vulnerability factors underlying the association between weight gain and psychosis; c) to provide information on new potential targets of intervention.

Self-imagination can enhance memory in individuals with schizophrenia

OBJECTIVE

Previous research has demonstrated that self-referential strategies can be applied to improve memory in various memory- impaired populations. However, little is known regarding the relative effectiveness of self-referential strategies in schizophrenia patients. The main aim of this study was to assess the effectiveness of a new self-referential strategy known as self- imagination (SI) on a free recall task.

METHODS

Twenty schizophrenia patients and 20 healthy controls intentionally encoded words under five instructions: superficial processing, semantic processing, semantic self-referential processing, episodic self-referential processing and semantic self- imagining. Other measures included depression, psychotic symptoms and cognitive measures.

RESULTS

We found a SI effect in memory as self- imagining resulted in better performance in memory retrieval than semantic and superficial encoding in schizophrenia patients. The memory boost for self-referenced information in comparison to semantic processing was not found for other self-referential strategies. In addition no relationship between clinical variables and free recall performances was found. In controls, the SI condition did not result in better performance. The three self-referential strategies yielded better free recall than both superficial and semantic encoding.

CONCLUSIONS

This study provides evidence of the clinical utility of self-imagining as a mnemonic strategy in schizophrenia patients.

Self-reference recollection effect and its relation to theory of mind: An investigation in healthy controls and schizophrenia

This study explores the links between the Self-Reference Effect (SRE) and Theory of Mind (ToM) in typical adults and patients with schizophrenia. Participants were assessed with a self-referential memory paradigm investigating the mnemonic effect of both semantic and episodic self-reference with a recognition task associated with the Remember/Know/Guess paradigm. They also completed a self-descriptive scale and shortened versions of the attribution of intention task and the reading the mind in the eyes test as measures of cognitive and affective ToM respectively. Unlike typical adults, the patients showed no semantic SRRE (correct recognition associated with remembering), and there was no episodic SRRE and no SRE (on the number of correct recognitions) in either group. Semantic SRRE was correlated with the affective ToM in patients and with the positivity of the self-concept in the healthy group. We discuss that patients and typical adults use different strategies during self and other-reflection.

Self-face recognition in the ultra-high risk for psychosis population

AIM

Phenomenological research indicates that disturbance of the basic sense of self may be a core phenotypic marker of schizophrenia spectrum disorders. Self-face recognition (SFR) is an experimental paradigm which can assess the basic sense of self. In this study, we used SFR to determine whether basic self-disturbance is present in the ultra-high risk (UHR) for psychosis population at the perceptual level.

METHODS

Twenty-three UHR individuals and 23 healthy comparison subjects were administered the SFR task. The study consisted of a 2 × 3 × 2 design: two group levels (UHR for psychosis group and the healthy comparison group); three task levels (self-famous task, self-stranger task, famous-stranger task); and two hand levels (left hand and right hand). Threshold limit values in face recognition were analysed.

RESULTS

The analysis indicated effects for group (F(1, 43) = 5.197, P < 0.05) and interaction effects between group and task (F = 4.767, P < 0.05). An independent samples t-test was used to compare the threshold limit values of the same task between the two groups. For self-famous task, the threshold limit values of the UHR group were higher than those of healthy group both in the left and right hands (t = 2.734, P < 0.05; t = 2.864, P < 0.05), but no significant difference was found in self-stranger task and famous-stranger task (P > 0.05).

CONCLUSIONS

This SFR study indicates that basic self-disturbance is present in the UHR for psychosis at the behavioural level in comparison with a healthy comparison group.

Evaluation of trait adjectives and ego pathology in schizophrenia: an N400 study

The N400, an event-related brain potential (ERP), can be triggered by semantic or arithmetic violations in visual or auditory stimulus material. Schizophrenia patients exhibit an altered N400 presumably resulting from impaired semantic memory associative networks. The present study investigates, whether an altered N400 can also be found in semantic violations of the own self-concept. We use simple descriptive sentences to combine semantics with the self-concept in order to explore differences and possible deficits in schizophrenia patients. Schizophrenia patients and controls were shown trait adjectives in reference to themselves. Participants had to decide if the presented trait adjective was congruent or incongruent with their own self-concept. Only in controls, the N400 was significantly more negative in the incongruent compared to the congruent condition. Controls seemed to profit from a stable self-concept as they were faster in judging if a given trait was descriptive for the self than for someone else, which might result from processes related to the self-reference effect. Interestingly, in schizophrenia patients, the higher the scores for ego pathology were, the smaller the N400 effect turned out to be. The diminished N400 effect is probably associated with a disturbed self-concept in schizophrenia.

Denial of illness in schizophrenia as a disturbance of self-reflection, self-perception and insight

BACKGROUND

A substantial proportion of schizophrenia patients deny aspects of their illness to others, which may indicate a deeper disturbance of 'insight' and a self-reflection deficit. The present study used a 'levels-of-processing' mnemonic paradigm to examine whether such patients engage in particularly brief and shallow self-reflection during mental illness-related self-evaluation.

METHODS

26 schizophrenia patients with either an overall acceptance or denial of their illness and 25 healthy controls made timed decisions about the self-descriptiveness, other-person-descriptiveness and phonological properties of mental illness traits, negative traits and positive traits, before completing surprise tests of retrieval for these traits.

RESULTS

The acceptance patients and denial patients were particularly slow in their mental illness-related self-evaluation, indicating that they both found this exercise particularly difficult. Both patient groups displayed intact recognition but particularly reduced recall for self-evaluated traits in general, possibly indicating poor organisational processing during self-reflection. Lower recall for self-evaluated mental illness traits significantly correlated with higher denial of illness and higher illness-severity. Whilst explicit and implicit measures of self-perception corresponded in the healthy controls (who displayed an intact positive>negative 'self-positivity bias') and acceptance patients (who displayed a reduced self-positivity bias), the denial patients' self-positivity bias was explicitly intact but implicitly reduced.

CONCLUSIONS

Schizophrenia patients, regardless of their illness-attitudes, have a particular deficit in recalling new self-related information that worsens with increasing denial of illness. This deficit may contribute towards rigid self-perception and disturbed self-awareness and insight in patients with denial of illness.

Me, myself and I: temporal dysfunctions during self-evaluation in patients with schizophrenia

Self-concept is deeply affected in schizophrenia. Positive symptoms in particular are related to disturbed self/other distinctions. The neural networks underlying self-evaluation in schizophrenia have barely been investigated. The study reported here involved 13 patients with schizophrenia and 13 matched controls. During functional MRI, participants decided in three conditions whether the presented positive and negative personality traits characterized themselves, an intimate person, or included a certain letter. Based on the responses, each experimental condition was designed using a flexible factorial model. Controls and patients showed a similar behavioral pattern during self-evaluation, with group comparison revealing decreased activation in patients in the left inferior temporal gyrus and both temporal poles during self-ascription of traits, and in the anterior medial prefrontal cortex during evaluation of an intimate person. In patients, positive symptoms correlated positively with brain activation in the left parahippocampus during trait self-ascription. Hence, while evaluating themselves, schizophrenia patients revealed decreased activation in areas related to self-awareness overlapping with networks involved in theory of mind, empathy and social knowledge. Moreover, patients' brain activation during self-reflection was affected by the current positive symptomatology. The close interaction between self and other highlights the clinical and social relevance of self-processing deficits in schizophrenia.

Cognitive functioning correlates of self-esteem and health locus of control in schizophrenia

AIM

The study aimed to investigate the relationship among sociodemographic factors, neurocognitive factors, self-esteem, and health locus of control in patients diagnosed with schizophrenia. We examined the self-esteem, internal health locus of control, and external health locus of control through sociodemographic and neurocognitive factors.

METHODS

Forty-six schizophrenic patients and 31 healthy residents from the community or hospital were recruited as the control group. All subjects participated in the self-esteem questionnaire, health locus of control questionnaire, and a series of neuropychological measures.

RESULTS

Multiple regression analysis revealed that inhibition of attention and external health locus of control were predictors for self-esteem (r=-0.30, P<0.05; r=0.41, P<0.01); inhibition of attention and external health locus of control were contributors for internal health locus of control (r=-0.43, P<0.01; r=0.61, P<0.001); and education was related to external health locus of control (r=-0.31, P<0.05).

CONCLUSION

The current study integrated background characteristics and cognitive function to better understand the impact of self-esteem and health locus of control in schizophrenia. The findings indicated that inhibition of attention, external health locus of control, and education contributed to self-esteem, internal health locus of control and external health locus of control. However, the overall predicted variance accounted for by these predictors was small; thus, further research is necessary to examine imperative variables related with self-esteem and health locus of control in schizophrenia.

The neural correlates of positive self-evaluation and self-related memory

Humans tend to have a positive self-evaluation (PSE). To what extent positive self-perception is interacting with valenced self-related memories is debated. The underlying neural substrates are not adequately explained yet. To explore the cerebral correlates of PSE and its influence on memory, 24 healthy subjects were asked during fMRI to decide in two conditions whether presented positive and negative personality traits characterized their own selves (self-evaluation) or an intimate other (other-evaluation). A lexical condition served as control task. In a subsequent unannounced recognition task, trait adjectives had to be classified as old or new. Activation during positive self- vs positive other-evaluation was found in the medial ventral and dorsolateral prefrontal gyri, the parahippocampus and the supplementary motor area. Memory increased for positive personality traits and traits that had been referred to oneself or the other. In contrast to adjectives of the other-evaluation or lexical condition, recollection of negative vs positive traits of the self-evaluation condition specifically induced increased activation in the hippocampus and several prefrontal and temporal areas. Our data imply a specific network for PSE (although intimate others are perceived similarly). Moreover, memory for traits contradicting PSE resulted in activation increases indicating greater cognitive effort and emotional involvement.

Altered resting state complexity in schizophrenia

The complexity of the human brain's activity and connectivity varies over temporal scales and is altered in disease states such as schizophrenia. Using a multi-level analysis of spontaneous low-frequency fMRI data stretching from the activity of individual brain regions to the coordinated connectivity pattern of the whole brain, we investigate the role of brain signal complexity in schizophrenia. Specifically, we quantitatively characterize the univariate wavelet entropy of regional activity, the bivariate pairwise functional connectivity between regions, and the multivariate network organization of connectivity patterns. Our results indicate that univariate measures of complexity are less sensitive to disease state than higher level bivariate and multivariate measures. While wavelet entropy is unaffected by disease state, the magnitude of pairwise functional connectivity is significantly decreased in schizophrenia and the variance is increased. Furthermore, by considering the network structure as a function of correlation strength, we find that network organization specifically of weak connections is strongly correlated with attention, memory, and negative symptom scores and displays potential as a clinical biomarker, providing up to 75% classification accuracy and 85% sensitivity. We also develop a general statistical framework for the testing of group differences in network properties, which is broadly applicable to studies where changes in network organization are crucial to the understanding of brain function.