Impaired verbal source monitoring in schizophrenia: an intermediate trait vulnerability marker?

A systematic review of performance-based assessment studies on cognitive biases in schizophrenia spectrum psychoses and clinical high-risk states: A summary of 40 years of research

Cognitive models of psychosis have stimulated empirical studies on cognitive biases involved in schizophrenia spectrum psychoses and their symptoms. This systematic review aimed to summarize the studies on the role of cognitive biases as assessed in different performance-based tasks in schizophrenia spectrum psychoses and clinical high-risk states. We focused on five cognitive biases linked to psychosis, i.e., aberrant salience, attentional biases, source monitoring biases, jumping to conclusions, and bias against disconfirmatory evidence. We identified N = 324 studies published in N = 308 articles fulfilling inclusion criteria. Most studies have been cross-sectional and confirmed that the schizophrenia spectrum psychoses are related to exaggerated cognitive biases compared to healthy controls. On the contrary, less evidence suggests a higher tendency for cognitive biases in the UHR sample. The only exceptions were source monitoring and jumping to conclusions, which were confirmed to be exaggerated in both clinical groups. Hallucinations and delusions were the most frequent symptoms studied in the context of cognitive biases. Based on the findings, we presented a hypothetical model on the role of interactions between cognitive biases or additive effects of biases in shaping the risk of psychosis. Future research is warranted for further development of cognitive models for psychosis.

Diverging effects of mentalization based treatment for patients with borderline personality disorder and schizophrenia: an explorative comparison

Introduction

There is robust evidence that both patients with schizophrenia (SCZ) and borderline personality disorder (BPD) display mentalizing difficulties. Less is known however about differences in the way mentalization based treatment (MBT) impacts mentalizing capacity in SCZ and BPD patients. This study compares the impact of MBT on mentalizing capacity in individuals with SCZ and BPD.

Method

The thematic apperception test was used to measure mentalizing capacity. It was administered at the beginning and end of treatment to 26 patients with SCZ and 28 patients with BPD who enrolled in an 18-month long MBT program. For comparison a sample of 28 SCZ patients who did not receive MBT was also included. Using the social cognition and object-relations system, these narratives were analyzed and scored. Missing data was imputed and analyzed using intention-to-treat ANCOVAs with post-treatment measures of mentalizing capacity as dependent variables, group type as independent variable and baseline mentalizing capacities as covariates.

Results

Results showed that patients with BPD showed significantly more improvement on several measures of mentalizing, including complexity of representation (ηp2 = 0.50, ppooled < 0.001), understanding of social causality (ηp2 = 0.41, ppooled < 0.001) and emotional investment in relationships (ηp2 = 0.41, ppooled < 0.001) compared to patients with SCZ who received MBT. No differences were found regarding affect-tone of relationships (ηp2 = 0.04, ppooled = 0.36). SCZ patients who received MBT showed greater performance on understanding of social causality (ηp2 = 0.12, ppooled = 0.01) compared to SCZ patients who did not receive MBT, but no differences were observed on complexity of representations, capacity for emotional investment or affect-tone of relationships.

Discussion

Patients with BPD performed better after receiving MBT on three dimensions of mentalizing capacity than SCZ patients who received MBT. Remarkably, SCZ patients who received MBT performed better on one dimension of mentalizing capacity compared to SCZ patients who did not receive MBT. Whereas MBT for BPD clearly involves improvement on most aspects of mentalizing, MBT for SCZ seems to thwart a further decline of other-oriented, cognitive mentalizing. Treatment goals should be adapted toward these disorder-specific characteristics.

Language abnormalities in schizophrenia: binding core symptoms through contemporary empirical evidence

Both the ability to speak and to infer complex linguistic messages from sounds have been claimed as uniquely human phenomena. In schizophrenia, formal thought disorder (FTD) and auditory verbal hallucinations (AVHs) are manifestations respectively relating to concrete disruptions of those abilities. From an evolutionary perspective, Crow (1997) proposed that "schizophrenia is the price that Homo sapiens pays for the faculty of language". Epidemiological and experimental evidence points to an overlap between FTD and AVHs, yet a thorough investigation examining their shared neural mechanism in schizophrenia is lacking. In this review, we synthesize observations from three key domains. First, neuroanatomical evidence indicates substantial shared abnormalities in language-processing regions between FTD and AVHs, even in the early phases of schizophrenia. Second, neurochemical studies point to a glutamate-related dysfunction in these language-processing brain regions, contributing to verbal production deficits. Third, genetic findings further show how genes that overlap between schizophrenia and language disorders influence neurodevelopment and neurotransmission. We argue that these observations converge into the possibility that a glutamatergic dysfunction in language-processing brain regions might be a shared neural basis of both FTD and AVHs. Investigations of language pathology in schizophrenia could facilitate the development of diagnostic tools and treatments, so we call for multilevel confirmatory analyses focused on modulations of the language network as a therapeutic goal in schizophrenia.

Self-monitoring in schizophrenia: Weighting exteroceptive visual signals against self-generated vestibular cues

Disturbances in self-monitoring are core symptoms of schizophrenia. Some research suggests an over-reliance on exteroceptive cues and a reduced weighting of self-generated interoceptive signals to guide perception. The vestibular sense provides important self-generated information about the body in space. Alterations of vestibular function are reported in schizophrenia, but it is unknown whether internally generated vestibular information is discounted in favour of exteroceptive input. In this study, we test for evidence of an over-reliance on exteroceptive visual cues and a reduced weighting of vestibular signals in guiding perception. In a group of individuals with schizophrenia and healthy controls, we used a well-studied visual illusion - the Tilt Illusion - to probe the respective weight given to visual and vestibular cues in judging line orientation. The Tilt Illusion reveals that perceived orientation of a vertical grating is biased by the orientation in its surround. This illusion increases when the head is tilted, due to the reduced reliability of vestibular information that would otherwise provide an internally generated reference for vertical. We predicted that an over-reliance on exteroceptive cues in schizophrenia would lead to a reduced susceptibility to the effects of head position on Tilt Illusion strength. We find no difference between patients and controls. Both groups show comparable Tilt Illusion magnitudes that increase when the head is tilted. Thus, our findings suggest that chronic patients with schizophrenia adequately combine self-generated vestibular cues and exteroceptive visual input to judge line verticality. A stronger reliance on exteroceptive information over internally generated signals in guiding perception is not evident in our data. Deficits in self-monitoring might therefore be modality specific or state dependant.

Understanding source monitoring subtypes and their relation to psychosis: a systematic review and meta-analysis

AIMS

Source monitoring (SM) is the metacognitive ability to determine the origin of one's experiences. SM is altered in primary psychiatric psychosis, although relationships between SM subtypes, other cognitive domains and symptoms are unclear. Our aims were to synthesize evidence comparing psychosis -with and without hallucinations- and healthy controls classifying SM subtypes by source discrimination (internal/external/reality monitoring) and stimulus modality (visual/auditory/imagined/performed).

METHODS

This systematic review adopted Preferred Reporting Items for Systematic Reviews and Meta-Analyses, Meta-analyses Of Observational Studies in Epidemiology and Population, Intervention, Comparison and Outcomes guidelines. Core demographical and clinical parameters were extracted. Newcastle-Ottawa Scale was used as quality check. SM differences between (i) psychosis patients versus healthy controls and (ii) patients with versus without hallucinations were investigated via random-effect model meta-analysis. The primary effect size measure was standardized mean difference (SMD) in each SM subtype performance (error or accuracy). Heterogeneity, publication biases and meta-regressions were assessed.

RESULTS

Five thousand two hundred and fifty-six records were screened to finally include 44 studies (1566 patients, 1175 controls). Mean Newcastle-Ottawa score was 7.41 out of 9. Few studies measured SM associations with cognition (n = 9) and symptoms (n = 19), with heterogeneous findings. SM performance across all measures was reduced in psychosis versus healthy controls (SMD = 0.458). Internal SM (SMD: errors = 0.513; accuracy = 0.733) and imagined stimuli (SMD: errors = 0.688; accuracy = 0.978) were specifically impaired. Patients with versus without hallucinations showed SM deficits only for externalizing (SMD = 0.410) and imagined/auditory (SMD = 0.498/0.277) errors.

CONCLUSION

The proposed classifications highlight specific SM deficits for internal/imagined stimuli in psychosis, providing evidence-based indications to design and interpret future studies.

Impaired self-recognition in individuals with no full-blown psychotic symptoms represented across the continuum of psychosis: a meta-analysis

BACKGROUND

Impairments in self-recognition (i.e. recognition of own thoughts and actions) have been repeatedly shown in individuals with schizophrenia. According to classical clinical characterizations, schizophrenia is included in a continuum encompassing a large range of genetic statuses, psychotic states and symptoms. The current meta-analysis aims to determine whether self-recognition is affected by individuals within the psychosis continuum.

METHOD

Three populations were considered: people with an at-risk mental state for psychosis (ARMS), hallucination-prone individuals and unaffected relatives of patients with schizophrenia. Eleven studies contrasted self-recognition between these three populations (n = 386) and healthy controls (n = 315) and four studies used correlational analysis to estimate comparable effects (n = 629). Eligible studies used experimental paradigms including source-monitoring and self-monitoring.

RESULTS

We observed significantly reduced self-recognition accuracy in these populations [g = -0.44 (-0.71 to -0.17), p = 0.002] compared to controls. No influence of the type of population, experimental paradigm or study design was observed.

CONCLUSION

The present analysis argues for self-recognition deficits in populations with no full-blown psychotic symptoms represented across the continuum of psychosis.

Effect of non-pharmacological interventions on source memory processes in the early course of psychosis: A systematic review

People with a psychotic disorder suffer from major cognitive impairments which prevent their functional recovery. Source memory impairments have been shown to be associated with psychotic symptoms and even to precede their onset. Source memory has thus been hypothesized as a cognitive precursor of psychosis. However, few interventions targeting source memory are included in current therapeutic approaches for early psychosis.

AIM

This systematic review aimed to identify non-pharmacological interventions for early psychosis which have impacted source memory processes.

METHODS

Studies were selected from nine databases when they included: (a) a non-pharmacological intervention involving a sample of patients with early-onset psychotic disorder or subclinical psychotic symptoms; and (b) effects on source memory processes, measured directly or inferred through an episodic memory task.

RESULTS

Thirteen studies were identified, including two cognitive remediation programs and one repetitive transcranial magnetic stimulation treatment that reported beneficial effects on source memory.

CONCLUSIONS

Relevant intervention strategies for source memory impairments were identified. This review points up a need to further develop interventions targeting theoretically defined source memory concepts and assess their effects with specific and valid tasks. Recommendations regarding underlying mechanisms which could have a beneficial impact on source memory may provide guidance for the future development of early psychosis interventions.

Disrupted Sense of Agency as a State Marker of First-Episode Schizophrenia: A Large-Scale Follow-Up Study

Background: Schizophrenia is often characterized by a general disruption of self-processing and self-demarcation. Previous studies have shown that self-monitoring and sense of agency (SoA, i.e., the ability to recognize one's own actions correctly) are altered in schizophrenia patients. However, research findings are inconclusive in regards to how SoA alterations are linked to clinical symptoms and their severity, or cognitive factors. Methods: In a longitudinal study, we examined 161 first-episode schizophrenia patients and 154 controls with a continuous-report SoA task and a control task testing general cognitive/sensorimotor processes. Clinical symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS). Results: In comparison to controls, patients performed worse in terms of recognition of self-produced movements even when controlling for confounding factors. Patients' SoA score correlated with the severity of PANSS-derived "Disorganized" symptoms and with a priori defined symptoms related to self-disturbances. In the follow-up, the changes in the two subscales were significantly associated with the change in SoA performance. Conclusion: We corroborated previous findings of altered SoA already in the early stage of schizophrenia. Decreased ability to recognize self-produced actions was associated with the severity of symptoms in two complementary domains: self-disturbances and disorganization. While the involvement of the former might indicate impairment in self-monitoring, the latter suggests the role of higher cognitive processes such as information updating or cognitive flexibility. The SoA alterations in schizophrenia are associated, at least partially, with the intensity of respective symptoms in a state-dependent manner.

Misattributing speech and jumping to conclusions: A longitudinal study in people at high risk of psychosis

Biases in cognition such as Jumping to Conclusions (JTC) and Verbal Self-Monitoring (VSM) are thought to underlie the formation of psychotic symptoms. This prospective study in people with an At Risk Mental State (ARMS) for psychosis examined how these cognitive biases changed over time, and predicted clinical and functional outcomes. Twenty-three participants were assessed at clinical presentation and a mean of 31 months later. Performance on a JTC and VSM tasks were measured at both time points. Relationships to symptom severity, level of function and the incidence of psychotic disorder were then examined. The levels of symptoms, function and VSM all improved over time, while JTC was stable. Five participants (22%) developed a psychotic disorder during the follow-up period, but the risk of transition was not related to performance on either task at baseline, or to longitudinal changes in task performance. JTC performance correlated with symptom severity at baseline and follow-up. Similarly, performance on the two tasks was not related to the level of functioning at follow-up. Thus, while the ARMS is associated with both VSM and JTC biases, neither predict the onset of psychosis or the overall functional outcome.

Mentalization and Psychosis: A Rationale for the Use of Mentalization Theory to Understand and Treat Non-affective Psychotic Disorder

Social functioning can be severely impaired in non-affective psychotic disorder (NAPD). Current models of psychosis pathogenesis do not tend to focus on social dysfunction and pharmacological treatment fails to ameliorate it. In this article, we propose that mentalization theory provides a valuable contribution to the understanding and treatment of NAPD. Impaired mentalizing may contribute to both positive and negatives symptoms as well as social dysfunction observed in NAPD. Furthermore, impaired mentalizing may help explain the relation between childhood abuse, insecure attachment and psychosis. Mentalization based treatment may contribute to the functional recovery of NAPD patients as it targets the social cognitive processes underlying social interaction. The article includes a description of the principles of MBT in general, specific characteristics of using MBT with patients with NAPD and a clinical vignette to illustrate these principles.

Impaired action self-monitoring and cognitive confidence among ultra-high risk for psychosis and first-episode psychosis patients

Background

Self-monitoring biases and overconfidence in incorrect judgments have been suggested as playing a role in schizophrenia spectrum disorders. Little is known about whether self-monitoring biases may contribute to early risk factors for psychosis. In this study, action self-monitoring (i.e., discrimination between imagined and performed actions) was investigated, along with confidence in judgments among ultra-high risk (UHR) for psychosis individuals and first-episode psychosis (FEP) patients.

Methods

Thirty-six UHR for psychosis individuals, 25 FEP patients and 33 healthy controls (CON) participated in the study. Participants were assessed with the Action memory task. Simple actions were presented to participants verbally or non-verbally. Some actions were required to be physically performed and others were imagined. Participants were asked whether the action was presented verbally or non-verbally (action presentation type discrimination), and whether the action was performed or imagined (self-monitoring). Confidence self-ratings related to self-monitoring responses were obtained.

Results

The analysis of self-monitoring revealed that both UHR and FEP groups misattributed imagined actions as being performed (i.e., self-monitoring errors) significantly more often than the CON group. There were no differences regarding performed actions as being imagined. UHR and FEP groups made their false responses with higher confidence in their judgments than the CON group. There were no group differences regarding discrimination between the types of actions presented (verbal vs non-verbal).

Conclusions

A specific type of self-monitoring bias (i.e., misattributing imagined actions with performed actions), accompanied by high confidence in this judgment, may be a risk factor for the subsequent development of a psychotic disorder.

Reality-monitoring deficits and visual hallucinations in schizophrenia

The presence of visual hallucinations in addition to auditory hallucinations (V + AH) is associated with poor prognosis in patients with schizophrenia. However, little consideration has been given to these symptoms and their underlying cognitive bases remain unclear. Based on cognitive models of hallucinations, we hypothesized that V + AH are underpinned by an impairment in reality-monitoring processes. The objective of the present study was to test whether reality-monitoring deficits were associated with V + AH in schizophrenia. This study examined reality-monitoring abilities in two groups of patients with schizophrenia: a group of patients with V + AH (n = 24) and a group of patients with AH only (n = 22). Patients with V + AH were significantly more likely to misremember imagined words as being perceived from an external source, compared to patients with AH only (p = 0.008, d = -0.82). In other words, V + AH patients display a larger externalization bias than patients with AH only. One explanation for these results could be that experiencing hallucinations in two sensory modalities may contribute to increased vividness of mental imagery and, in turn, lead to disruption in reality-monitoring processes. This study helps to refine our understanding of the cognitive processes underlying the presence of both auditory and visual hallucinations in patients with schizophrenia.

The role of attachment anxiety in the relationship between childhood trauma and schizophrenia-spectrum psychosis

Childhood trauma (CT) is a comprehensive concept encompassing experiences of sexual, physical, and emotional abuse, and neglect during childhood and adolescence. Patients with schizophrenia-spectrum psychosis (SSP) display higher rates of CT than healthy controls. Among the potential mediators of this association, insecure attachment has gained attention and empirical validation. The present study aimed to extend existing knowledge on this field by exploring the role of the two attachment dimensions, attachment anxiety and attachment avoidance, in the CT-SSP association. A clinical sample of 63 SSP inpatients was compared to a healthy control group on CT and attachment style measures. Correlations between CT, attachment dimensions and psychopathology were sought. Mediation analyses were also performed to examine whether attachment anxiety and/or attachment avoidance mediated the CT-SSP association. Patients displayed higher rates of CT and insecure attachment than controls. Attachment anxiety and severity of Mother Antipathy were linked to severity of hallucinations. Attachment anxiety was recognized as the sole mediator of the CT-SSP association. Our findings suggest that individuals with severe CT and increased attachment anxiety represent a risk population warranting early clinical attention, regular monitoring and tailored therapeutic interventions aimed at reducing the psychological impact of trauma.

Resting-State Networks of Adolescents Experiencing Depersonalization-Like Illusions: Cross-sectional and Longitudinal Findings

The mirror-gazing task (MGT) experimentally induces illusions, ranging from simple color changes in the specular image of oneself, to depersonalization-like anomalous self-experiences (ASE) as in experiencing one's specular image as someone else. The objective was to characterize how connectivity in resting-state networks (RSNs) differed in adolescents reporting such depersonalization-like ASEs during the MGT, in a cross-sectional (Y1) and in a longitudinal manner (a year after). 75 adolescents were recruited; for the cross-sectional analysis, participants were split into 2 groups: those who reported depersonalization-like ASEs on the MGT (ASE), and those who did not (NoASE). For the longitudinal analysis, participants were split into 3 groups whether they experienced MGT depersonalization-like ASEs: only at Y1 (Remitters), both times (Persisters), or never (Controls). Participants also filled out self-reports assessing schizotypal personality (Schizotypal Personality Questionnaire [SPQ]), and underwent resting-state functional MRI procedure (rs-fMRI). A group level Independent Component Analysis (ICA) was conducted and voxel-wise inter-group differences within RSNs were examined. The rs-fMRI analysis revealed lower connectivity of specific visual areas within the primary visual network (PVN), and higher connectivity of regions within the Default Mode Network (DMN) when contrasting the ASE and NoASE groups. The areas that were atypically connected within the PVN further presented differential pattern of connectivity in the longitudinal analysis. Atypical connectivity of visual area within the DMN at Y1 was associated with higher scores on the disorganized dimension of schizotypy at the second evaluation. The present study uncovers a subtle signature in the RSNs of non-clinical adolescents who experienced task-induced ASEs.

Lower P300 amplitudes for internally-generated events in patients with schizophrenia

BACKGROUND

Patients with schizophrenia demonstrate difficulty differentiating internally-generated from externally-generated events. An excessive deployment of attention to external events as well as poor processing of self-generated events has been proposed to explain this misattribution. This study was done to understand the neurophysiological basis of source monitoring bias in schizophrenia.

METHODS

Seventeen patients and fourteen healthy controls completed a two-stage source monitoring task involving solving a three-letter jumbled word either by the participant or a computer following which they had to identify the correct source of the word - solved by self (internal source monitoring, ISM) or by computer (external source monitoring, ESM) - while EEG was recorded. P300 amplitude and latency were computed separately for ISM and ESM conditions.

RESULTS

P300 amplitude for ISM condition was lower in patients with schizophrenia compared to controls over right and left parietal regions. Additionally, P300 amplitude for ISM condition was lower compared to ESM condition in patients over right and left parietal regions. However, P300 amplitude for ESM condition did not differ significantly between the groups. In contrast to P300 amplitude, there was no significant difference in P300 latency in ISM or ESM condition within or between the groups.

CONCLUSION

P300 amplitude was lower for internally-generated but not externally-generated events in patients with schizophrenia. These findings suggest that patients allocate less attentional resources to internally generated events resulting in poorer processing and consequent misattribution of their source of origin. This study provides the first specific electrophysiological evidence of impaired source monitoring in schizophrenia.

Mentalizing impairment as a mediator between reported childhood abuse and outcome in nonaffective psychotic disorder

Reported childhood abuse has been linked to the severity of clinical symptoms and social dysfunction in non-affective psychotic disorder. Impaired mentalizing ability may be one of the mechanisms accounting for this effect. This study examined whether impaired mentalizing mediates the effect of reported childhood abuse on positive symptoms, negative symptoms, and social dysfunction. Eighty-seven patients with non-affective psychotic disorder were examined. Reported childhood abuse was measured using the Childhood Experience of Care and Abuse interview. Additionally, the Social Functioning Scale and the Positive and Negative Syndrome Scale were used. The Hinting Task was used to measure mentalizing impairment. Reported childhood abuse was significantly related to the severity of positive and negative symptoms, not to social dysfunction. Reported childhood abuse was also related to mentalizing impairment. Mentalizing impairment was related to negative symptoms, but not to positive symptoms or social dysfunction. Mentalizing impairment accounted for 40% of the association between reported childhood abuse and negative symptoms, indicating partial mediation. A sensitivity analysis revealed that the mediating effect was only observed in those who reported fairly severe childhood abuse.

Brain Mechanisms of Reality Monitoring

Reality monitoring processes are necessary for discriminating between internally generated information and information that originated in the outside world. They help us to identify our thoughts, feelings, and imaginations, and to distinguish them from events we may have experienced or have been told about by someone else. Reality monitoring errors range from confusions between real and imagined experiences, that are byproducts of normal cognition, to symptoms of mental illness such as hallucinations. Recent advances support an emerging neurocognitive characterization of reality monitoring that provides insights into its underlying operating principles and neural mechanisms, the differing ways in which impairment may occur in health and disease, and the potential for rehabilitation strategies to be devised that might help those who experience clinically significant reality monitoring disruption.

Abnormal agency experiences in schizophrenia patients: Examining the role of psychotic symptoms and familial risk

Experiencing self-agency over one's own action outcomes is essential for social functioning. Recent research revealed that patients with schizophrenia do not use implicitly available information about their action-outcomes (i.e., prime-based agency inference) to arrive at self-agency experiences. Here, we examined whether this is related to symptoms and/or familial risk to develop the disease. Fifty-four patients, 54 controls, and 19 unaffected (and unrelated) siblings performed an agency inference task, in which experienced agency was measured over action-outcomes that matched or mismatched outcome-primes that were presented before action performance. The Positive and Negative Syndrome Scale (PANSS) and Comprehensive Assessment of Symptoms and History (CASH) were administered to assess psychopathology. Impairments in prime-based inferences did not differ between patients with symptoms of over- and underattribution. However, patients with agency underattribution symptoms reported significantly lower overall self-agency experiences. Siblings displayed stronger prime-based agency inferences than patients, but weaker prime-based inferences than healthy controls. However, these differences were not statistically significant. Findings suggest that impairments in prime-based agency inferences may be a trait characteristic of schizophrenia. Moreover, this study may stimulate further research on the familial basis and the clinical relevance of impairments in implicit agency inferences.

Mapping autobiographical memory in schizophrenia: Clinical implications

Increasing evidence suggests that impaired autobiographical memory (AM) mechanisms may be associated with the onset and maintenance of psychopathology. However, there is not yet a comprehensive review of the components of autobiographical memory in schizophrenic patients. The first aim of this review is a synthesis of evidence about the functioning of AM in schizophrenic patients. The main autobiographical elements reviewed in schizophrenic patients include the study of overgeneral memory (form); self-defining memories (contents); consciousness during the process of retrieval (awareness), and the abnormal early reminiscence bump (distribution). AM impairments have been involved in the clinical diagnosis and prognosis of other psychopathologies, especially depression. The second aim is to examine potential parallels between the mechanisms responsible for the onset and maintenance of disturbed AM in other clinical diagnosis and the mechanisms of disturbed autobiographical memory functioning in schizophrenic patients. Cognitive therapies for schizophrenic patients are increasingly demanded. The third aim is the suggestion of key elements for the adaptation of components of autobiographical recall in cognitive therapies for the treatment of symptoms and consequences of schizophrenia.

Detecting facial emotion recognition deficits in schizophrenia using dynamic stimuli of varying intensities

BACKGROUND

Deficits in facial emotion recognition have been associated with functional impairments in patients with Schizophrenia (SZ). Whilst a strong ecological argument has been made for the use of both dynamic facial expressions and varied emotion intensities in research, SZ emotion recognition studies to date have primarily used static stimuli of a singular, 100%, intensity of emotion. To address this issue, the present study aimed to investigate accuracy of emotion recognition amongst patients with SZ and healthy subjects using dynamic facial emotion stimuli of varying intensities. To this end an emotion recognition task (ERT) designed by Montagne (2007) was adapted and employed.

METHODS

47 patients with a DSM-IV diagnosis of SZ and 51 healthy participants were assessed for emotion recognition. Results of the ERT were tested for correlation with performance in areas of cognitive ability typically found to be impaired in psychosis, including IQ, memory, attention and social cognition.

RESULTS

Patients were found to perform less well than healthy participants at recognising each of the 6 emotions analysed. Surprisingly, however, groups did not differ in terms of impact of emotion intensity on recognition accuracy; for both groups higher intensity levels predicted greater accuracy, but no significant interaction between diagnosis and emotional intensity was found for any of the 6 emotions. Accuracy of emotion recognition was, however, more strongly correlated with cognition in the patient cohort.

DISCUSSION

Whilst this study demonstrates the feasibility of using ecologically valid dynamic stimuli in the study of emotion recognition accuracy, varying the intensity of the emotion displayed was not demonstrated to impact patients and healthy participants differentially, and thus may not be a necessary variable to include in emotion recognition research.

Attachment, Neurobiology, and Mentalizing along the Psychosis Continuum

In this review article, we outline the evidence linking attachment adversity to psychosis, from the premorbid stages of the disorder to its clinical forms. To better understand the neurobiological mechanisms through which insecure attachment may contribute to psychosis, we identify at least five neurobiological pathways linking attachment to risk for developing psychosis. Besides its well documented influence on the hypothalamic-pituary-adrenal (HPA) axis, insecure attachment may also contribute to neurodevelopmental risk through the dopaminergic and oxytonergic systems, as well as bear influence on neuroinflammation and oxidative stress responses. We further consider the neuroscientific and behavioral studies that underpin mentalization as a suite of processes potentially moderating the risk to transition to psychotic disorders. In particular, mentalization may help the individual compensate for endophenotypical impairments in the integration of sensory and metacognitive information. We propose a model where embodied mentalization would lie at the core of a protective, resilience response mitigating the adverse and potentially pathological influence of the neurodevelopmental cascade of risk for psychosis.

Psychotic reactions to daily life stress and dopamine function in people with severe hearing impairment

BACKGROUND

Minor stresses measured in daily life have repeatedly been associated with increased momentary psychotic experiences, both in individuals with psychotic disorders and in persons who are genetically at an increased risk for these disorders. Severe hearing impairment (SHI) is an environmental risk factor for psychotic disorder, possibly due to the experience of social exclusion. The aim of the current study is to investigate whether people with SHI exhibit higher levels of psychotic reactivity to social stressors in daily life than normal-hearing controls and whether this reactivity is associated with decreased baseline dopamine (DA) D2/3 receptor availability and/or elevated DA release following a dexamphetamine challenge.

METHOD

We conducted an experience sampling study in 15 young adults with SHI and 19 matched normal-hearing controls who had previously participated in a single photon emission computed tomography study measuring DA D2/3 receptor availability and DA release in response to dexamphetamine.

RESULTS

The association between social stress and momentary psychotic experiences in daily life was stronger among SHI participants than among normal-hearing controls. Interactions between social stress and baseline striatal DA D2/3 receptor availability or DA release were not significant in multilevel models of momentary psychotic experiences including age, sex and tobacco use.

CONCLUSIONS

While both elevated striatal DA release and elevated psychotic stress reactivity have been found in the same population defined by an environmental risk factor, SHI, their inter-relationship cannot be established. Further research is warranted to clarify the association between biological and psychological endophenotypes and psychosis risk.

Towards a cognitive model of hallucinations in the course of alcohol dependence? A source monitoring-based pilot study

BACKGROUND

We investigated whether source-monitoring deficits (here a discrimination between imagined and performed actions) underlie hallucinations among patients with a history of hallucinations in the course of their alcohol dependence.

METHOD

We assessed 29 patients with alcohol dependence who had no history of hallucinations during their course of alcoholism and 29 patients with a history of at least one episode of hallucinations of any modality during their course of alcohol dependency. The control group consisted of 24 healthy participants. Participants were assessed with an action memory task. Simple actions were presented to the participants verbally or non-verbally. Some actions were performed physically and others were imagined. In the recognition phase, participants were asked whether the action was presented verbally or non-verbally (action presentation type discrimination) and whether the action was performed or imagined (self-monitoring). A confidence score related to self-monitoring responses was also obtained.

RESULTS

Alcoholics with a history of hallucinations misremembered imagined actions as perceived ones more frequently than patients without hallucinations, but not the reverse. Only patients with a history of hallucinations committed more errors of this type than healthy subjects. There were no group differences regarding discrimination between an action presentation type. Both clinical groups committed errors with a higher degree of confidence than healthy subjects.

CONCLUSIONS

Our results tentatively suggest that a specific type of source-monitoring deficit (i.e., confusing imagery with reality) may be involved in the hallucinations in patients with alcohol dependence. The findings are discussed in the light of a transdiagnostic approach to hallucinations.

N-Acetyl-Aspartate Level is Decreased in the Prefrontal Cortex in Subjects At-Risk for Schizophrenia

Reduced N-acetyl-aspartate (NAA) levels have been reported in the prefrontal cortex (PFC) in patients with schizophrenia using proton magnetic resonance spectroscopy. However, it is unclear whether this NAA reduction predates the illness onset and is reported in subjects at-risk for developing schizophrenia (HRS). The aim of this study was to assess NAA levels in the PFC in HRS. We hypothesized that HRS display lower NAA levels than healthy controls in the PFC. Studies assessing levels of NAA/Creatine (NAA/Cr) in the PFC in HRS were extracted from literature. Meta-analysis tools were used to compute effect sizes of nine selected studies meeting our inclusion criteria (clinical and/or genetic HRS, groups of HRS, and healthy controls matched for age and gender, spectral acquisition in the PFC). We reported that HRS exhibited a significant lower NAA/Cr level (2.15 ± 0.29; n = 208) than healthy controls (2.21 ± 0.32; n = 234) in the PFC with a medium pooled effect size [Hedges's g = -0.42; 95% confidence interval: (-0.61; -0.23); p < 0.0001] corresponding to an average 5.7% of NAA/Cr decrease. Secondary analysis revealed that this reduction was observed in young HRS (<40 years old) who have not reached the peak age of risk for schizophrenia (-11%, g = -0.82, p < 0.00001) but not in old HRS (>40 years old) who have already passed the peak age (g = 0.11, p = 0.56), when they are compared with their matched healthy controls. Our findings suggest that the NAA/Cr reduction in the PFC reported in patients with schizophrenia is observable only in HRS who have not passed the peak age of risk for schizophrenia. NAA/Cr level in the PFC could therefore be considered as a biological vulnerability marker of schizophrenia.

Neurocognitive predictors of source monitoring in schizophrenia

RATIONALE

Source monitoring (SM) is a metacognitive process involved in making judgments about the origin of information by recruiting cognitive processes. Deficits in SM have been linked to positive symptoms of schizophrenia. We investigated whether certain neurocognitive functions - specifically attention, working memory, and organizational sequencing - were associated with SM in a sample of schizophrenia patients.

METHODS

Attention (Auditory Continuous Performance Test), organizational sequencing (Trail-Making Test B-A), working memory (Digits Backward), and internal SM were assessed in 45 outpatients diagnosed with schizophrenia or schizoaffective disorder.

RESULTS

Standard multiple regression analysis showed attention, working memory and organizational sequencing together predicted SM. Organizational sequencing was the only significant individual predictor, with better organizational sequencing ability being associated with better SM. Hierarchical regression analysis showed that working memory by itself did not result in a significant predictive model of SM, but adding organizational sequencing led to a significant change from the working memory model and resulted in a significant overall model, accounting for 26% of the variance in SM.

CONCLUSIONS

Neurocognitive functions were associated with SM in schizophrenia. Organizational sequencing, which requires an awareness of self-generated actions, predicted SM performance even after controlling for working memory.

Self-recognition deficits in schizophrenia patients with auditory hallucinations: a meta-analysis of the literature

Theories about auditory hallucinations in schizophrenia suggest that these experiences occur because patients fail to recognize thoughts and mental events as self-generated. Different theoretical models have been proposed about the cognitive mechanisms underlying auditory hallucinations. Regardless of the cognitive model being tested, however, experimental designs are almost identical in that they require a judgment regarding whether an action was self-originated or not. The aim of the current study was to integrate all available literature for a meta-analysis on this topic and reach conclusions about self-recognition performance in (1) patients with schizophrenia compared with healthy controls and (2) patients with auditory hallucinations compared with patients without these symptoms. A comprehensive literature review identified 23 studies that contrasted the performance of schizophrenia patients with healthy controls (1370 participants) and 9 studies that directly compared patients with and without auditory hallucinations (315 participants). We found significantly reduced self-recognition performance in schizophrenia patients, which was more pronounced in patients with auditory hallucinations compared with patients without. In patients with hallucinations, this pattern of performance was specific to self-recognition processes and not to the recognition of new external information. A striking finding was the homogeneity in results across studies regardless of the action modality, timing delay, and design used to measure self-recognition. In summary, this review of studies from the last 30 years substantiates the view that self-recognition is impaired in patients with schizophrenia and particularly those with auditory hallucinations. This suggests an association, perhaps a causal one, between such deficit and hallucinatory experiences in schizophrenia.

Impaired discrimination between imagined and performed actions in schizophrenia

The main aim of the present study was to investigate whether a specific type of source monitoring, namely self-monitoring for actions (differentiation between imagined and performed actions), is disrupted in schizophrenia. Persons diagnosed with schizophrenia (n=32) and healthy participants (n=32) were assessed with an action memory task. Simple actions were presented to the participants either verbally (short instructions) or nonverbally (icons). Some of the items required participants to physically perform the action whereas other actions had to be imagined. In the recognition phase of the study, participants were asked whether an action was previously displayed (verbally or nonverbally), whether it was a new action (not presented before), and if they had performed or imagined the action. In addition, participants were asked how confident they were in their decision. Participants in the group with schizophrenia significantly more often misattributed imagined actions as performed and vice versa and were more convinced about their wrong decision than participants in the control group. Patients revealed worse recognition for both verbal and nonverbal actions. In accordance with prior studies, we found that patients were less confident in their correct answers than healthy subjects. However, no enhanced confidence in incorrect answers was found. There was no observed significant relationship between source misattributions and the severity of psychopathological symptoms. Our findings suggest tentatively general source monitoring deficits in schizophrenia.

Reality monitoring and its association with social functioning in schizophrenia

Reality monitoring, or the ability to discriminate internal from external information present in short-term memory, is relevant in the study of schizophrenia. Previous research has linked monitoring impairments with psychotic symptoms and certain forms of communication disturbance. The focus of the present study was to test the hypothesis that there would be specific relationships between reality monitoring in patients with schizophrenia and current and pre-morbid social functioning, beyond the effects of general verbal ability. Fifty outpatients with schizophrenia or schizoaffective disorder were assessed for internal/external reality monitoring deficits, general verbal intelligence, and both current and pre-morbid social functioning. Associations between these variables were assessed. Exploratory analyses also were conducted to determine whether specific types of reality monitoring errors were related to social functioning. Results showed that (a) overall accuracy in reality monitoring was related to pre-morbid social functioning beyond the effects of verbal ability, (b) sensitivity to old versus new information in reality monitoring was related to current social functioning, and (c) a say-report-think reality monitoring error was significantly associated with pre-morbid social functioning. The results support the hypothesis of an association between reality monitoring sensitivity and social functioning.

Sense of agency is altered in patients with a putative psychotic prodrome

BACKGROUND

Sense of agency (SoAg)--the experience of controlling one's own actions and their consequences--has been studied in schizophrenia but not in the earlier stages of the disease, i.e. in patients with a putative psychotic prodrome (PP). Previous research has shown that time judgments of voluntary actions can provide an implicit measure of the SoAg.

METHOD

30 PP patients and 30 healthy controls performed voluntary key presses while watching a rotating clock hand on a monitor. After each key press they had to estimate the time of the action (based on the perceived position of the clock hand at the time of the key press). By varying the probability with which the simple manual action was followed by a tone, we investigated whether shifts in perceptual estimates of the operant action towards a resulting effect depended on the actual occurrence of the effect (retrospective process) or on the prediction that the effect will occur.

RESULTS

PP patients differed from healthy controls but their results did not resemble previous findings in schizophrenia patients. PP patients showed numerically--but not significantly--stronger temporal linkage between action and consequence than healthy controls. Retrospective and predictive influences on action binding were stronger in PP patients. Furthermore, the altered influence of prediction was significantly correlated to ego-psychopathology.

DISCUSSION

Distortions of agency constitute a core feature of the disease that is already present in the PP but may evolve further with progression of the illness. Distortions of agency may thus represent a promising additional predictive risk factor for transition to psychosis in PP patients.

Avolition and expressive deficits capture negative symptom phenomenology: implications for DSM-5 and schizophrenia research

The DSM-5 formulation presents an opportunity to refine the negative symptom assessments that are crucial for a schizophrenia diagnosis. This review traces the history of negative symptom constructs in neuropsychiatry from their earliest conceptualizations in the 19th century. It presents the relevant literature for distinguishing between different types of negative symptoms. Although a National Institute of Mental Health consensus initiative proposed that there are five separate negative symptom domains, our review of the individual items demonstrates no more than three negative symptom domains. Indeed, numerous factor analyses of separate negative symptom scales routinely identify only two domains: 1) expressive deficits, which include affective, linguistic and paralinguistic expressions, and 2) avolition for daily life and social activities. We propose that a focus on expressive deficits and avolition will be of optimum utility for diagnosis, treatment-considerations, and research purposes compared to other negative symptom constructs. We recommend that these two domains should be assessed as separate dimensions in the DSM-5 criteria.

Neural correlates of reality monitoring during adolescence

BACKGROUND

Reality monitoring processes serve the critical function of discriminating between externally derived information and self-generated information. Several reality monitoring studies with healthy adult participants have identified the anterior prefrontal cortex (PFC) as consistently engaged during the recollection of self-generated contextual cues. Furthermore, reduced activity of medial PFC has been linked with schizotypal trait expression of delusion and hallucination-like symptoms in healthy adults undergoing fMRI reality-monitoring tasks. The present study seeks to examine the cerebral underpinnings of reality monitoring during adolescence, a developmental stage where the expression of schizotypal traits may increase risk for psychosis.

METHOD

A group of 33 adolescents, assessed using the Schizotypal Personality Scale (SPQ), underwent fMRI while performing a reality monitoring task. After an encoding session where the subject or the experimenter read out a series of complete or incomplete word pairs, subjects were presented with the first word of studied word pairs and asked whether the corresponding word had been: (1) perceived or produced (context monitoring), or (2) read by the subject or by the experimenter (origin monitoring).

RESULTS

Analyses revealed a common set of activated brain areas during both context and origin monitoring conditions. When compared to context monitoring, origin monitoring was associated with greater activation in anterior PFC within Brodmann area 10 (BA 10). Correlation analyses revealed that reduced signal change in BA 10 during origin monitoring was associated with greater schizotypal trait expression.

CONCLUSION

Much like adults performing a similar reality monitoring task, adolescents exhibit a common pattern of brain activity during origin and context monitoring, with functional specialization within the prefrontal cortex involving preferential activation of BA 10 during origin monitoring. Greater schizotypal trait expression appears to be significantly associated to reduced BA 10 activity during origin monitoring trials. Results are discussed in relation to cortical specialization within the PFC and trait expression during adolescence.

Avolition and expressive deficits capture negative symptom phenomenology: implications for DSM-5 and schizophrenia research

The DSM-5 formulation presents an opportunity to refine the negative symptom assessments that are crucial for a schizophrenia diagnosis. This review traces the history of negative symptom constructs in neuropsychiatry from their earliest conceptualizations in the 19th century. It presents the relevant literature for distinguishing between different types of negative symptoms. Although a National Institute of Mental Health consensus initiative proposed that there are five separate negative symptom domains, our review of the individual items demonstrates no more than three negative symptom domains. Indeed, numerous factor analyses of separate negative symptom scales routinely identify only two domains: 1) expressive deficits, which include affective, linguistic and paralinguistic expressions, and 2) avolition for daily life and social activities. We propose that a focus on expressive deficits and avolition will be of optimum utility for diagnosis, treatment-considerations, and research purposes compared to other negative symptom constructs. We recommend that these two domains should be assessed as separate dimensions in the DSM-5 criteria.

[Source monitoring: general presentation and review of literature in schizophrenia]

SOURCE MONITORING FRAMEWORK: Source monitoring refers to the ability to remember the origin of information. Three source monitoring processes can be distinguished: external source monitoring, internal or self-monitoring and reality monitoring (i.e. discrimination between internal and external sources of information). Source monitoring decisions are based on memory characteristics recorded such as perceptions, contextual information or emotional reactions and heuristic or more controlled judgement processes.

BRAIN STRUCTURES

Several studies suggested that specific structures in the prefrontal and the mediotemporal lobes are the main areas implicated in source monitoring.

ASSESSMENT

A typical source monitoring paradigm includes an items generation stage and a second stage of recognition of items (old versus new) and identification of their sources: external (usually the examiner) or internal (the subject). Several indices can be calculated based on the raw data such as the number of false alarms, attribution biases or discrimination indexes. To date, there is no standardized source monitoring task and differences in the type of items used (words, pictures), in the cognitive or emotional effort involved or in the delay between the two test stages, contribute to the heterogeneity of results.

FACTORS INFLUENCING SOURCE MONITORING

Factors such as age (either very young or very old) and emotions influence source monitoring performances. Influence of gender was not properly explored, whereas the role of IQ and selective attention is still debated.

SOURCE MONITORING DEFICITS IN NEUROLOGICAL DISORDERS

Source monitoring deficits are observed mainly in disorders affecting frontotemporal areas, such as frontal trauma, Alzheimer's disease or frontotemporal dementia.

SOURCE MONITORING AND SCHIZOPHRENIA

Source monitoring errors (e.g. external misattribution of self-generated information) are observed in schizophrenia and seem to correlate with positive symptomatology, in particular auditory hallucinations, thought intrusion and alien control symptoms. These results are of particular interest in clinical research because source monitoring is one of the rare cognitive tests showing a correlation with the positive dimension. Source monitoring deficits have been proposed as a potential explanation for the positive symptoms and some, but not all studies lent support to this hypothesis. Heterogeneity of studied samples, in particular different criteria to define hallucinating subjects (e.g. currently versus anytime during their lives), could explain the discordant results.

SOURCE MONITORING IN PSYCHIATRIC DISORDERS WITHIN THE SCHIZOPHRENIC SPECTRUM

Source monitoring impairments were observed in pharmacological models of psychosis, in first degree relatives of schizophrenic patients, and also in the general population associated with schizotypal dimensions. These results support a relationship between source monitoring deficits and some of the symptomatic dimensions of the schizophrenic spectrum but still await replication.

SOURCE MONITORING AND OTHER PSYCHIATRIC DISORDERS

Some studies found source monitoring deficits in other psychiatric conditions such as mania or obsessive-compulsive disorder. Thus, those studies suggest that source monitoring deficits may be not specific to schizophrenia.

CONCLUSION

Source monitoring competencies are critical for good (i.e. adapted) everyday functioning. Source monitoring deficits have been suggested as a potential explanation for some (or all) positive psychotic symptoms. However, to date, methodological inconsistencies (especially with regard to test design and choice of subjects' samples) have precluded firm, definite conclusions.

Familiarity and recollection processes in patients with recent-onset schizophrenia and their unaffected parents

Episodic memory deficits are present in patients with schizophrenia (SZ) and their unaffected relatives and could be considered as a cognitive indicator of genetic vulnerability to SZ. The present study, involving patients with SZ as well as their parents, used experimental tasks specifically designed to disentangle the contribution of familiarity and recollection processes to episodic memory. The performance of patients with SZ (n=26) and their unaffected parents (n=35) was compared with that of healthy control groups matched on socio-demographic variables (controls of patients, n=26; controls of parents, n=35) on two memory tasks assessing recollection and familiarity. The first task was designed to investigate item recognition and memory for item-spatial context associations whereas the second targeted item-item associations. The results revealed an overall episodic memory deficit in patients with SZ, encompassing both familiarity and recollection, while unaffected parents showed a dysfunction restricted to the recollection process. Our study highlights differences and similarities in the source of the episodic memory deficit found in patients with SZ and their unaffected parents, and it suggests that recollection could act as a cognitive endophenotype of SZ. The results also suggest that use of experimental tasks represents a promising method in the search of cognitive endophenotypes in SZ.

Monitoring of self-generated speech in adolescents with 22q11.2 deletion syndrome

OBJECTIVES

The present report examines the monitoring of self-generated speech in adolescents with 22q11.2 deletion syndrome (22q11DS), a neurogenetic disorder associated with very high risk for psychosis.

DESIGN

Between-participant group design.

METHODS

In this study, 20 adolescents with 22q11DS, 19 age- and IQ-matched controls, and 19 typically developing adolescents were enrolled. Participants completed a speech-monitoring task, in which they were asked to silently or overtly read a series of word and non-word items. Subjects then filled out a recognition sheet containing studied and novel items. They were asked to identify the previously studied item, and to attribute the reading condition (silent vs. overt) under which each recognized item was encoded.

RESULTS

Adolescents with 22q11DS commit more external attribution errors compared to both control groups, by exhibiting an increased tendency to report silently read items as though they had been read overtly. Further, results suggest that increased cognitive effort exacerbates the external attribution tendency in adolescents with 22q11DS. Increased internal attributions were also observed in the IQcontrol and 22q11DS groups in comparison to typically developing adolescents.

CONCLUSIONS

Similarly to adult individuals exhibiting positive symptoms of psychosis, adolescents with 22q11DS exhibit an external attribution bias for inner speech. This bias seems to be exacerbated by increased cognitive effort, suggesting a failure to recollect information pertaining to cognitive operations during self-monitoring. Cognitive biases associated to schizophrenia may be detected in adolescents at very high risk for psychosis. These observations provide further evidence for the presence of an external attribution bias along the clinical continuum of psychosis vulnerability.

Cognitive and emotional associations to positive schizotypy during adolescence

BACKGROUND

Sub-clinical symptoms of psychosis such as hallucinations and delusions, known as positive schizotypy, constitute one of the strongest predictive factors for adult psychotic disorders. Recent cognitive models suggest that the expression of positive schizotypy is associated with depression, anxiety, metacognitive beliefs and self-monitoring deficits. In this study, we present empirical data on the relationships positive schizotypy hold with both emotional and cognitive factors.

METHODS

A sample of 163 adolescents (77 females) participated in this study (mean age 15.3, 12-18 years). Subjects filled out self-report questionnaires assessing the emotional dimensions of depression and anxiety, as well as metacognitive beliefs. Self-monitoring skills were assessed using an action monitoring paradigm sensitive to dysfunctions associated with psychosis-proneness. Multivariate regression models were employed to examine emotional and cognitive contributions to positive schizotypy during adolescence.

RESULTS

Analyses revealed that dimensions of depression, anxiety, and metacognitive beliefs significantly correlated with the expression of positive schizotypy. When accounting for the effects of depression and metacognitive beliefs in adolescents reporting hallucinations, self-monitoring dysfunctions seemed to represent a significant factor in the expression of positive schizotypy.

CONCLUSION

The present results suggest that the expression of positive schizotypy during adolescence is modulated by emotional factors of depression and anxiety, as well as metacognitive beliefs and self-monitoring dysfunctions. The current data lend some evidence that supports the cognitive-developmental account of positive symptom formation before the onset of a psychotic disorder.

A disturbed sense of self in the psychosis prodrome: linking phenomenology and neurobiology

Interest in the early phase of psychotic disorders has risen dramatically in recent years. Neurobiological investigations have focused specifically on identifying brain changes associated with the onset of psychosis. The link between these neurobiological findings and the complex phenomenology of the early psychosis period is not well understood. In this article, we re-cast some of these observations, primarily from neuroimaging studies, in the context of phenomenological models of "the self" and disturbance thereof in psychotic illness. Specifically, we argue that disturbance of the basic or minimal self ("ipseity"), as articulated in phenomenological literature, may be associated with abnormalities in midline cortical structures as observed in neuroimaging studies of pre-onset and early psychotic patients. These findings are discussed with regards to current ideas on the neural basis of self-referential mental activity, including the notion of a putative "default-mode" of brain function, and its relation to distinguishing between self- and other-generated stimuli. Further empirical work examining the relationship between neurobiological and phenomenological variables may be of value in identifying risk markers for psychosis onset.

Self and other in schizophrenia: a cognitive neuroscience perspective

OBJECTIVE

Recent basic science data indicate that in healthy individuals, self-referential processing and social cognition rely on common neural substrates. The authors assessed self-referential source memory and social cognition in a large sample of schizophrenia outpatients and healthy comparison subjects in order to compare how these critical processes are associated in the two groups.

METHOD

Ninety-one schizophrenia outpatients and 30 healthy comparison subjects were assessed on measures of basic social cognition and source memory for previously learned word items: self-generated, externally presented, and new words. Partial correlations and multiple regression analysis were used to test the association between social cognition measures and source memory performance and the contributions of source memory and general cognitive abilities to a social cognition composite score.

RESULTS

Schizophrenia patients demonstrated significantly lower source memory for self-generated items (self-referential source memory) relative to comparison subjects but showed intact external source memory. In both groups, self-referential source memory and social cognition showed strong correlations. When the effects of general cognitive abilities were controlled for, these correlations were attenuated in the schizophrenia patients. Regression analysis revealed discrepancies between groups in the cognitive functions contributing to social cognition performance.

CONCLUSIONS

Impaired self-referential source memory represents a unique cognitive deficit in schizophrenia. Moreover, the strong association between self-referential source memory and social cognition seen in healthy subjects is reduced in schizophrenia and is moderated by general cognitive abilities. Impairments in the neurocognitive system that underlies both self-referential and social cognition provide a parsimonious explanation for the disturbances in the sense of self and other that characterize schizophrenia.

No evidence for a differential deficit of reality monitoring in schizophrenia: a meta-analysis of the associative memory literature

INTRODUCTION

Patients with schizophrenia exhibit deficits in memory performance, particularly when required to bind together disparate items (associative memory). Yet the literature on associative memory is decidedly mixed, with some studies showing large deficits and other showing none.

METHODS

The aims of this meta-analysis were to determine an overall effect size for the associative memory deficit in patients with schizophrenia and to examine two potential moderating variables related to this impairment: the nature of the memory being tested (pair vs. source recognition) and the inclusion or exclusion of novel items as part of the recognition test.

RESULTS

We found that the mean effect sizes were large for pair recognition (r=.50) and medium for source recognition (r=.29), with a significant difference between the two recognition types. Contrary to a priori hypotheses, there were no differences in the effect sizes across the various types of source memory (i.e., internal, external, or reality monitoring). There was, however, a significant difference in the effect sizes between those studies that included novel items as part of the memory test (r=.26) and those that did not (r=.44).

CONCLUSION

These findings suggest that the associative memory deficit in schizophrenia is not specific to self/other distinctions, but is rather a more global effect seen across testing conditions. In addition, memory tests that do not include new items appear to maximise this effect, perhaps by removing a potential response outlet for subjects who lack confidence in the accuracy of their memory performance.

Neurocognitive allied phenotypes for schizophrenia and bipolar disorder

Psychiatric disorders are genetically complex and represent the end product of multiple biological and social factors. Links between genes and disorder-related abnormalities can be effectively captured via assessment of phenotypes that are both associated with genetic effects and potentially contributory to behavioral abnormalities. Identifying intermediate or allied phenotypes as a strategy for clarifying genetic contributions to disorders has been successful in other areas of medicine and is a promising strategy for identifying susceptibility genes in complex psychiatric disorders. There is growing evidence that schizophrenia and bipolar disorder, rather than being wholly distinct disorders, share genetic risk at several loci. Further, there is growing evidence of similarity in the pattern of cognitive and neurobiological deficits in these groups, which may be the result of the effects of these common genetic factors. This review was undertaken to identify patterns of performance on neurocognitive and affective tasks across probands with schizophrenia and bipolar disorder as well as unaffected family members, which warrant further investigation as potential intermediate trait markers. Available evidence indicates that measures of attention regulation, working memory, episodic memory, and emotion processing offer potential for identifying shared and illness-specific allied neurocognitive phenotypes for schizophrenia and bipolar disorder. However, very few studies have evaluated neurocognitive dimensions in bipolar probands or their unaffected relatives, and much work in this area is needed.

Deficient relational binding processes in adolescents with psychosis: evidence from impaired memory for source and temporal context

INTRODUCTION

Findings from the literature consistently revealed episodic memory deficits in adolescents with psychosis. However, the nature of the dysfunction remains unclear. Based on a cognitive neuropsychological approach, a theoretically driven paradigm was used to generate valid interpretations about the underlying memory processes impaired in these patients.

METHODS

A total of 16 inpatient adolescents with psychosis and 19 individually matched controls were assessed using an experimental task designed to measure memory for source and temporal context of studied words. Retrospective confidence judgements for source and temporal context responses were also assessed.

RESULTS

On word recognition, patients had more difficulty than controls discriminating target words from neutral distractors. In addition, patients identified both source and temporal context features of recognised items less often than controls. Confidence judgements analyses revealed that the difference between the proportions of correct and incorrect responses made with high confidence was lower in patients than in controls. In addition, the proportion of high-confident responses that were errors was higher in patients compared to controls.

CONCLUSIONS

These findings suggest impaired relational binding processes in adolescents with psychosis, resulting in a difficulty to create unified memory representations. Our findings on retrospective confidence data point to impaired monitoring of retrieved information that may also impair memory performance in these individuals.

Episodic memory bias and the symptoms of schizophrenia

Much of the research on episodic memory in schizophrenia spectrum disorders has focused on memory deficits and how they relate to clinical measures such as outcome. Memory bias refers to the modulatory influence that state or trait psychopathology may exert on memory performance for specific categories of stimuli, often emotional in nature. For example, subjects suffering from depression frequently have better memory for negative stimuli than for neutral or positive ones. This dimension of memory function has received only scant attention in schizophrenia research but could provide fresh new insights into the relation between symptoms and neurocognition. This paper reviews the studies that have explored memory biases in individuals with schizophrenia. With respect to positive symptoms, we examine studies that have explored the link between persecutory delusions and memory bias for threatening information and between psychosis and a memory bias toward external source memory. Although relatively few studies have examined negative symptoms, we also review preliminary evidence indicating that flat affect and anhedonia may lead to some specific emotional memory biases. Finally, we present recent findings from our group delineating the relation between emotional valence for faces and memory bias toward novelty and familiarity, both in schizophrenia patients and in healthy control subjects. A better understanding of the biasing effects of psychopathology on memory in schizophrenia (but also on other cognitive functions, such as attention, attribution, and so forth) may provide a stronger association between positive and negative symptoms and memory function. Memory measures sensitive to such biases may turn out to be stronger predictors of clinical and functional outcome.

Emotion recognition and genetic vulnerability to schizophrenia

BACKGROUND

Epidemiological studies of schizophrenia suggest that this disorder has a substantial genetic component. Cognitive and social abilities, as well as the volumes of brain regions involved in emotion processing, have been found to be distributed along a continuum when comparing patients, siblings and controls, with siblings showing intermediate scores.

AIMS

To establish whether facial expression recognition is impaired in unaffected siblings of patients.

METHOD

Emotion and gender recognition were evaluated in a three-group pre-post study design in drug-naive patients with first-episode schizophrenia (n=40) and their unaffected siblings (n=30) compared with controls (n=26).

RESULTS

Patients and their healthy siblings showed impaired emotion recognition but normal gender recognition compared with controls. Patients'performance did not improve despite effective clinical stabilisation.

CONCLUSIONS

Impaired performance in healthy siblings and time stability in patients provides evidence of impairment of facial emotion recognition as an actual phenotype of schizophrenia.