Theory of Mind and Motion Perception in Schizophrenia

Disrupted third visual pathway function in schizophrenia: Evidence from real and implied motion processing

Impaired motion perception in schizophrenia has been associated with deficits in social-cognitive processes and with reduced activation of visual sensory regions, including the middle temporal area (MT+) and posterior superior temporal sulcus (pSTS). These findings are consistent with the recent proposal of the existence of a specific 'third visual pathway' specialized for social perception in which motion is a fundamental component. The third visual pathway transmits visual information from early sensory visual processing areas to the STS, with MT+ acting as a critical intermediary. We used functional magnetic resonance imaging to investigate functioning of this pathway during processing of naturalistic videos with explicit (real) motion and static images with implied motion cues. These measures were related to face emotion recognition and motion-perception, as measured behaviorally. Participants were 28 individuals with schizophrenia (Sz) and 20 neurotypical controls. Compared to controls, individuals with Sz showed reduced activation of third visual pathway regions (MT+, pSTS) in response to both real- and implied-motion stimuli. Dysfunction of early visual cortex and pulvinar were also associated with aberrant real-motion processing. Implied-motion stimuli additionally engaged a wide network of brain areas including parietal, motor and frontal nodes of the human mirror neuron system. The findings support concepts of MT+ as a mediator between visual sensory areas and higher-order brain and argue for greater focus on MT+ contributions to social-cognitive processing, in addition to its well-documented role in visual motion processing.

Motion and Form Perception in Childhood-Onset Schizophrenia

(1) Background: Childhood-onset schizophrenia (COS) is a rare type of psychotic disorder characterized by delusions, hallucinations, grossly disorganized behavior, and poor psychosocial functioning. The etiology of COS is unknown, but neurodevelopmental factors are likely to play a critical role. A potential neurodevelopmental anomaly marker is the dorsal visual system dysfunction, which is implicated in motion perception, spatial functions, and attention. (2) Methods: To elucidate the role of the dorsal visual system in COS, we investigated 21 patients with COS and 21 control participants matched for age, sex, education, IQ, and parental socioeconomic status. Participants completed a motion and form coherence task, during which one assesses an individual's ability to detect the direction of motion within a field of moving elements or dots and to recognize a meaningful form or object from a set of fragmented or disconnected visual elements, respectively. (3) Results: The patients with COS were impaired in both visual tasks compared to the control participants, but the evidence for the deficit was more substantial for motion perception than for form perception (form: BF10 = 27.22; motion: BF10 = 6.97 × 106). (4) Conclusions: These results highlight the importance of dorsal visual stream vulnerability in COS, a potential marker of neurodevelopmental anomalies.

Disentangling the Relationships Between the Clinical Symptoms of Schizophrenia Spectrum Disorders and Theory of Mind: A Meta-analysis

BACKGROUND AND HYPOTHESIS

Previous studies have suggested links between clinical symptoms and theory of mind (ToM) impairments in schizophrenia spectrum disorders (SSD), but it remains unclear whether some symptoms are more strongly linked to ToM than others.

STUDY DESIGN

A meta-analysis (Prospero; CRD42021259723) was conducted to quantify and compare the strength of the associations between ToM and the clinical symptoms of SSD (Positive, Negative, Cognitive/Disorganization, Depression/Anxiety, Excitability/Hostility). Studies (N = 130, 137 samples) including people with SSD and reporting a correlation between clinical symptoms and ToM were retrieved from Pubmed, PsycNet, Embase, Cochrane Library, Science Direct, Proquest, WorldCat, and Open Gray. Correlations for each dimension and each symptom were entered into a random-effect model using a Fisher's r-to-z transformation and were compared using focused-tests. Publication bias was assessed with the Rosenthal failsafe and by inspecting the funnel plot and the standardized residual histogram.

STUDY RESULTS

The Cognitive/Disorganization (Zr = 0.28) and Negative (Zr = 0.24) dimensions revealed a small to moderate association with ToM, which was significantly stronger than the other dimensions. Within the Cognitive/Disorganization dimension, Difficulty in abstract thinking (Zr = 0.36) and Conceptual disorganization (Zr = 0.39) showed the strongest associations with ToM. The association with the Positive dimension (Zr = 0.16) was small and significantly stronger than the relationship with Depression/Anxiety (Zr = 0.09). Stronger associations were observed between ToM and clinical symptoms in younger patients, those with an earlier age at onset of illness and for tasks assessing a combination of different mental states.

CONCLUSIONS

The relationships between Cognitive/Disorganization, Negative symptoms, and ToM should be considered in treating individuals with SSD.

Heightened perception of illusory motion is associated with symptom severity in schizophrenia patients

Abnormal perceptual processing in schizophrenia may contribute to the development of positive symptoms such as hallucinations. Experimental findings suggest that such abnormalities result from impaired processing of local signals into complex cortical representations. Because complex processing is needed to generate the perception of illusory motion from local signals, deteriorated perception of illusory motion would be expected in schizophrenia. However, findings are mixed, and the relationship between complex motion processing and symptoms is unclear. Illusions with multiple flow components (e.g. rotation/expansion) are known to strongly engage specialized complex processing mechanisms that may be abnormal in schizophrenia, but have not yet been investigated. We used a recently constructed paradigm based on the Pinna-Brelstaff illusion to manipulate complex-flow illusory perception in a quantitative manner and probe associations with dimensional symptoms. In 102 patients and 90 controls, perceived speed and perceptual variability for the PBF were measured across a range of parameters. Meanwhile, eye movement was recorded and gaze parameters were analysed to examine effects on illusory perception. Our results showed that patients experienced faster illusory rotation than controls, while they made fewer eye fixations. This heightened illusory perception was significantly correlated with positive and general, but not negative, symptom scores. Our results indicate that unusual processing of complex-flow motion in patients may be specifically related to dimensional symptoms, which could provide a promising strategy for parsing heterogeneity in the schizophrenia syndrome. This further highlights the role of motion perception abnormalities in the pathophysiology of schizophrenia, thus encouraging future investigation into visual remediation therapeutics.

The Relationship Between Different Aspects of Theory of Mind and Symptom Clusters in Psychotic Disorders: Deconstructing Theory of Mind Into Cognitive, Affective, and Hyper Theory of Mind

Background: Several meta-analyses highlight pronounced problems in general Theory of Mind (ToM), the ability to infer other persons' mental states, in patients with psychosis in comparison to non-clinical controls. In addition, first studies suggest associations between Hyper-ToM, an exaggerated inference of mental states to others, and delusions. Research on different ToM subtypes (Cognitive ToM, Affective ToM, and Hyper-ToM) and symptom clusters of psychosis (positive, negative, and disorganized symptoms) have gathered conflicting findings. Thus, the present study examined group differences between patients with psychosis and non-clinical controls concerning Cognitive ToM/Affective ToM and Hyper-ToM. Further, the association between ToM subtypes and symptom clusters (positive, negative, and disorganized symptoms) were examined. Methods: Patients with psychotic disorders (n = 64, 1/3 with present delusions indicated by a minimum score of four in the PANSS P1 item) and non-clinical controls (n = 21) were examined with assessments of Cognitive ToM and Affective ToM abilities and Hyper-ToM errors using the Frith-Happé animations. Psychopathology was assessed using the Positive and Negative Syndrome Scale. Results: Patients with psychosis presented more pronounced problems in Cognitive and Affective ToM in comparison to non-clinical controls, whereas there were no group differences with regard to Hyper-ToM errors. Furthermore, deficits in Cognitive ToM were associated with general delusions, whereas problems in Affective ToM were associated with negative and disorganized symptoms. In addition, there was no association between Hyper-ToM errors and any symptoms when controlling for years of education. Conclusions: Our findings suggest that deficits in ToM subtypes might not be directly related to delusions and positive symptoms and are in line with more recently developed cognitive models of delusions. In addition, our results support the well-established finding of associations between ToM alterations and negative or disorganized symptoms. Our results shed light on the role of different dimensions of ToM in specific symptoms of psychosis.

Early Visual Processing Is Associated With Social Cognitive Performance in Recent-Onset Schizophrenia

BACKGROUND

Early-stage visual processing deficits are evident in chronic schizophrenia. Consistent with a cascade model of information processing, whereby early perceptual processes have downstream effects on higher-order cognition, impaired visual processing is associated with deficits in social cognition in this clinical population. However, the nature of this relationship in the early phase of illness is unknown. Here, we present data from a study of early visual processing and social cognitive performance in recent-onset schizophrenia (ROSz).

METHOD

Thirty-two people with ROSz and 20 healthy controls (HC) completed a visual backward masking task using stimuli of real world objects (Object Masking) to assess early-stage (i.e., 0-125 ms post-stimulus onset) visual processing. Subjects also completed two tasks of social cognition, one assessing relatively low-level processes of emotion identification (Emotion Biological Motion, EmoBio), and another assessing more complex, higher-order theory of mind abilities (The Awareness of Social Inference Test, TASIT). Group differences were tested with repeated measures ANOVAs and t-tests. Bivariate correlations and linear regressions tested the strength of associations between early-stage visual processing and social cognitive performance in ROSz.

RESULTS

For Object Masking, the mask interfered with object identification over a longer interval for ROSz than for HC [F (3.19, 159.35) = 8.51, p < 0.001]. ROSz were less accurate on the EmoBio task [t (50) = -3.36, p = 0.001] and on the TASIT compared to HC [F (1, 50) = 38.37, p < 0.001]. For the TASIT ROSz were disproportionately impaired on items assessing sarcasm detection [F (1, 50) = 4.30, p = 0.04]. In ROSz, better Object Masking performance was associated with better social cognitive performance [r EmoBio = 0.45, p < 0.01; r TASIT = 0.41, p < 0.02]. Regression analyses did not provide significant support for low-level social cognition mediating the relationship between visual processing and high-level social cognition.

CONCLUSION

Early-stage visual processing, low-level social cognition, and high-level social cognition were all significantly impaired in ROSz. Early-stage visual processing was associated with performance on the social cognitive tasks in ROSz, consistent with a cascade model of information processing. However, significant cascading effects within social cognition were not supported. These data suggest that interventions directed at early visual processing may yield downstream effects on social cognitive processes.

A meta-analysis of the associations between theory of mind and neurocognition in schizophrenia

Theory of mind (ToM) refers to the ability to infer the mental states of others. ToM is impaired in schizophrenia and these deficits seem to hinder functional recovery. ToM is thus an important, but complex treatment target, supported by several processes. A large number of studies report significant associations between ToM and neurocognition (e.g. memory, attention), but the neurocognitive domains that are most closely linked to ToM remain to be identified. A meta-analysis was conducted to estimate the magnitude of the associations between ToM and neurocognition in people with schizophrenia. Correlations were extracted from the relevant literature, transformed into effect sizes Zr and pooled as weighted means. Focused-tests were employed to test for differences between neurocognitive domains and for differences linked to the characteristics of ToM tasks. Ninety-one studies (N = 5462) were included. Moderate associations emerged between ToM and each neurocognitive domain (Zrs 0.27-0.43), with no significant difference between domains (χ2(8) = 11.89, p = 0.156). Within the domain of executive functions, abstraction showed a stronger association with ToM (χ2(4) = 18.93, p = 0.001). Several ToM tasks characteristics (e.g. modality of stimuli, type of mental state), were significantly related to the magnitude of the associations between ToM and executive functions, visuospatial/problem solving, attention and episodic memory. These results suggest that ToM is linked to a wide range of neurocognitive abilities in schizophrenia, and that ToM tasks are a significant moderator of these associations. The assessment and treatment of ToM should consider the neurocognitive profile of each patient to understand his difficulties and to tailor interventions.

Improvement of Theory of Mind in Schizophrenia: A 15-Year Follow-Up Study

Neurocognitive and social cognitive deficits are a hallmark of schizophrenia. The purpose of the present study was to investigate long-term changes in theory of mind (ToM), executive functions, lexical retrieval, and speed of information processing/attention in schizophrenia. We followed-up 31 outpatients with schizophrenia and 31 healthy control subjects for 15 years. ToM was assessed with the Reading the Mind from the Eyes Test (RMET), whereas neurocognitive functions were measured with the verbal fluency (VF) task (executive functions and lexical retrieval) and with the Digit-Symbol Substitution Test (DSST) (speed of information processing/attention). Clinical symptoms and general functioning were rated with the Positive and Negative Syndrome Scale (PANSS) and with the Global Assessment of Functioning (GAF) scale, respectively. At baseline assessment, patients with schizophrenia exhibited significant and generalized impairments on all measures. At follow-up, relative to the baseline, we observed marked improvements in ToM (RMET), stability in executive functions and lexical retrieval (VF), and a significant decline in psychomotor speed/attention (DSST) in schizophrenia. Clinical symptoms and psychosocial functions did not differ at baseline and at follow-up examinations (mild-to-moderate symptoms on the PANSS and moderate difficulty in social and occupational functions on the GAF). These results indicate that patients with schizophrenia with mild-to-moderate symptoms and functional deficits are characterized by improved ToM during over a decade.

A review of impaired visual processing and the daily visual world in patients with schizophrenia

Several studies have investigated perceptual processes in patients with schizophrenia. Research confirms that visual impairments are one of the most important features of schizophrenia. Many studies, using behavioral and psychological experiments, confirm that visual impairments can be used to determine illness severity, state, and best treatments. Herein, we review recent research pertaining to visual function in patients with schizophrenia and highlight the relationship between laboratory findings and subjective, real-life reports from patients themselves. The purpose of this review is to 1) describe visual impairments that manifest in patients with schizophrenia, 2) examine the relationship between visual dysfunction, assessed by laboratory tests, and the experiences of patients themselves, and 3) describe real-life experiences related to visual function in this population. In this review, the impairments of motion and color perception, perceptual organization, and scan paths are summarized, along with the relationship between laboratory findings and patients' real-world subjective experiences related to visual function.

Intact perception of coherent motion, dynamic rigid form, and biological motion in chronic schizophrenia

BACKGROUND

Prior studies have documented biological motion perception deficits in schizophrenia, but it remains unclear whether the impairments arise from poor social cognition, perceptual organization, basic motion processing, or sustained attention/motivation. To address the issue, we had 24 chronic schizophrenia patients and 27 healthy controls perform three tasks: coherent motion, where subjects indicated whether a cloud of dots drifted leftward or rightward; dynamic rigid form, where subjects determined the tilt direction of a translating, point-light rectangle; and biological motion, where subjects judged whether a human point-light figure walked leftward or rightward. Task difficulty was staircase controlled and depended on the directional variability of the background dot motion. Catch trials were added to verify task attentiveness and engagement.

RESULTS

Patients and controls demonstrated similar performance thresholds and near-ceiling catch trial accuracy for each task (uncorrected ps > 0.1; ds < 0.35). In all but the coherent motion task, higher IQ correlated with better performance (ps < 0.001).

CONCLUSION

Schizophrenia patients have intact perception of motion coherence, dynamic rigid form, and biological motion at least for our sample and set-up. We speculate that previously documented biological motion perception deficits arose from task or stimulus differences or from group differences in IQ, attention, or motivation.

Seeing the World as it is: Mimicking Veridical Motion Perception in Schizophrenia Using Non-invasive Brain Stimulation in Healthy Participants

Schizophrenia (Sz) is a mental health disorder characterized by severe cognitive, emotional, social, and perceptual deficits. Visual deficits are found in tasks relying on the magnocellular/dorsal stream. In our first experiment we established deficits in global motion processing in Sz patients compared to healthy controls. We used a novel task in which background optic flow produces a distortion of the apparent trajectory of a moving stimulus, leading control participants to provide biased estimates of the true motion trajectory under conditions of global stimulation. Sz patients were significantly less affected by the global background motion, and reported trajectories that were more veridically accurate than those of controls. In order to study the mechanism of this effect, we performed a second experiment where we applied transcranial electrical stimulation over area MT+ to selectively modify global motion processing of optic flow displays in healthy participants. Cathodal and high frequency random noise stimulation had opposite effects on trajectory perception in optic flow. The brain stimulation over a control site and in a control task revealed that the effect of stimulation was specific for global motion processing in area MT+. These findings both support prior studies of impaired early visual processing in Sz and provide novel approaches for measurement and manipulation of the underlying circuits.

Aberrant patterns of neural activity when perceiving emotion from biological motion in schizophrenia

Social perceptual deficits in schizophrenia are well established. Recent work suggests that the ability to extract social information from bodily cues is reduced in patients. However, little is known about the neurobiological mechanisms underlying this deficit. In the current study, 20 schizophrenia patients and 16 controls completed two tasks using point-light animations during fMRI: a basic biological motion task and an emotion in biological motion task. The basic biological motion task was used to localize activity in posterior superior temporal sulcus (pSTS), a critical region for biological motion perception. During the emotion in biological motion task, participants viewed brief videos depicting happiness, fear, anger, or neutral emotions and were asked to decide which emotion was portrayed. Activity in pSTS and amygdala was interrogated during this task. Results indicated that patients showed overall reduced activation compared to controls in pSTS and at a trend level in amygdala across emotions, despite similar task performance. Further, a functional connectivity analysis revealed that controls, but not patients, showed significant positive connectivity between pSTS and left frontal regions as well as bilateral angular gyrus during the emotion in biological motion task. These findings indicate that schizophrenia patients show aberrant neural activity and functional connectivity when extracting complex social information from simple motion stimuli, which may contribute to social perception deficits in this disorder.

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Perception of social information from bodily cues is impaired in schizophrenia.

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We examined neural correlates of perception of emotion from biological motion.

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Activity in amygdala and posterior superior temporal sulcus was reduced in patients.

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pSTS functional connectivity with frontal and parietal regions was reduced in patients.

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Aberrant neural responses may contribute to social perceptual deficits in schizophrenia.

Load-sensitive impairment of working memory for biological motion in schizophrenia

Impaired working memory (WM) is a core cognitive deficit in schizophrenia. Nevertheless, past studies have reported that patients may also benefit from increasing salience of memory stimuli. Such efficient encoding largely depends upon precise perception. Thus an investigation on the relationship between perceptual processing and WM would be worthwhile. Here, we used biological motion (BM), a socially relevant stimulus that schizophrenics have difficulty discriminating from similar meaningless motions, in a delayed-response task. Non-BM stimuli and static polygons were also used for comparison. In each trial, one of the three types of stimuli was presented followed by two probes, with a short delay in between. Participants were asked to indicate whether one of them was identical to the memory item or both were novel. The number of memory items was one or two. Healthy controls were more accurate in recognizing BM than non-BM regardless of memory loads. Patients with schizophrenia exhibited similar accuracy patterns to those of controls in the Load 1 condition only. These results suggest that information contained in BM could facilitate WM encoding in general, but the effect is vulnerable to the increase of cognitive load in schizophrenia, implying inefficient encoding driven by imprecise perception.

Social Cognition in Schizophrenia Patients and Their First-Degree Relatives

INTRODUCTION

Social cognition is a person's ability to configure the designs of relationships between themselves and others and to use these designs to guide social behaviors in a flexible manner. The models that are the most studied and describe social cognition are the theory of mind (ToM) and emotion recognition. This study was aimed to detect ToM and emotion recognition disorders in schizophrenia patients and their first-degree relatives.

METHODS

Thirty schizophrenia patients in remission, the first-degree relatives of schizophrenia patients (n=30), and 30 healthy volunteers who were paired with the patients in terms of age and duration of education were included in the study. The Positive and Negative Symptom Scale (PANSS), Dokuz-Eylül Theory of Mind Scale (DEToMS), Reading the Mind in the Eyes test, Facial Emotion Identification Test (FEIT), and Facial Emotion Discrimination Test (FEDT) were performed by the patients participating in this study.

RESULTS

ToM and emotion recognition were found to be defective in the schizophrenia patients and their relatives. The performances of ToM and emotion recognition were ranked as the schizophrenia group, family group, and control group, from the worst to the best. The schizophrenia group showed poor performance in all sub-components except irony. In the family group, the empathy subcomponent showed similar performance with the control group, whereas the subcomponents of the second-order false belief, metaphor, and faux pas tests showed similar performance with the patient group. There were differences among the three groups in the first-order false belief subscale as well as the total DEToMS. The patient and family groups showed the poorest performances, whereas the control group showed the best performance.

CONCLUSION

The detection of ToM and emotion recognition disorders in the remission period, regardless of the attack period and asymptomatic first-degree relatives, may support the view that the period of schizophrenia is an independent continuous variable.

Deficits of cognitive theory of mind and its relationship with functioning in individuals with an at-risk mental state and first-episode psychosis

Disturbance of theory of mind (ToM) and its relationship with functioning in schizophrenia is well documented; however, this is unclear in spectrum disorders like at-risk mental state (ARMS) and first-episode psychosis (FEP). To assess mental state reasoning ability, the total score of the Theory of Mind Picture Stories Task questionnaire was compared among 36 Japanese individuals with ARMS, 40 with FEP, and 25 healthy controls (HC). Pearson's correlations between ToM performance and global and social functioning indices were examined. ToM performance for FEP and ARMS subjects was significantly lower than that for HC, though the significance of the difference between the ARMS and HC disappeared when controlling for premorbid IQ. ToM deficits in ARMS subjects were confirmed only in the comprehension of higher-order false belief. Only among FEP subjects were ToM performance and global functioning significantly correlated, though the significance disappeared when controlling for neurocognitive performance or dose of antipsychotics. No significant correlation between ToM performance and social functioning was observed in the FEP and ARMS groups. The current findings suggest that ToM deficits emerge in ARMS subjects confined within a higher-order domain, and that the relationship between ToM impairment and functional deterioration might be established after psychosis onset.

Auditory top-down control and affective theory of mind in schizophrenia with and without hallucinations

Social cognitive impairments may represent a core feature of schizophrenia and above all are a strong predictor of positive psychotic symptoms. Previous studies could show that reduced inhibitory top-down control contributes to deficits in theory of mind abilities and is involved in the genesis of hallucinations. The current study aimed to investigate the relationship between auditory inhibition, affective theory of mind and the experience of hallucinations in patients with schizophrenia. In the present study, 20 in-patients with schizophrenia and 20 healthy controls completed a social cognition task (the Reading the Mind in the Eyes Test) and an inhibitory top-down Dichotic Listening Test. Schizophrenia patients with greater severity of hallucinations showed impaired affective theory of mind as well as impaired inhibitory top-down control. More dysfunctional top-down inhibition was associated with poorer affective theory of mind performance, and seemed to mediate the association between impairment to affective theory of mind and severity of hallucinations. The findings support the idea of impaired theory of mind as a trait marker of schizophrenia. In addition, dysfunctional top-down inhibition may give rise to hallucinations and may further impair affective theory of mind skills in schizophrenia.

Correlation between neuropsychological and social cognition measures and symptom dimensions in schizophrenic patients

Neurocognitive and social cognition deficits have been largely reported in Schizophrenia (SKZ) but their association with psychopathology remains uncertain. Our purpose was to explore the relationship between symptom dimensions and neuropsychological performances. We enrolled 35 stabilized schizophrenic outpatients of the Department of Psychiatry of Policlinico Hospital, University of Milan, who completed psychiatric Rating Scales, the Brief Assessment of Cognition in Schizophrenia (BACS) and the Executive and Social Cognition Battery (ESCB). Disorganized dimension seems to have the most significant impact on cognition, being associated with performance in several BACS subtests (verbal memory, working memory, motor speed, symbol coding, Tower of London) and ESCB tasks (MET and Hotel task number of tasks attempted, number of broken MET rules, sum of deviations in Hotel Task). Positive dimension correlated with performance in verbal fluency, negative dimension with IOWA Test results, cognitive dimension with MET number of inefficiencies and Eyes test score. Impulsive-aggressive and depressive dimensions weakly correlated only with Faux Pas test. Our study supports the existence of a specific disorganized dimension in SKZ, separated from cognitive dimension evaluated through clinical instruments (e.g. PANSS), but capable of influencing cognitive abilities. Furthermore, it strengthens the validity of ecological tasks in evaluating cognition in SKZ.

Judging Strangers' Trustworthiness is Associated with Theory of Mind Skills

Trusting people requires evaluating them to assess their trustworthiness. Evaluating a stranger's intentions is likely to be one method of assessing trustworthiness. The present study tested the hypothesis that judgments of trustworthiness are associated with mind reading skills, also called theory of mind (ToM). We tested a group of healthy participants and a group of patients with paranoid schizophrenia. Both groups made ToM judgments and judged the trustworthiness of strangers. Participants were also assessed for their disposition to trust as well as levels of paranoid belief. As anticipated, healthy participants had a normal ToM scores and patients with paranoid schizophrenia had poor ToM scores. In paranoid patients, better ability to read others' minds was associated with judging others as more trustworthy, while the reverse was found in the healthy participants (better mind reading was associated with judging others as less trustworthy), suggesting a non-linear relationship between trust in others and being able to read their intentions.

Absent activation in medial prefrontal cortex and temporoparietal junction but not superior temporal sulcus during the perception of biological motion in schizophrenia: a functional MRI study

BACKGROUND

Patients with schizophrenia show disturbances in both visual perception and social cognition. Perception of biological motion (BM) is a higher-level visual process, and is known to be associated with social cognition. BM induces activation in the "social brain network", including the superior temporal sulcus (STS). Although deficits in the detection of BM and atypical activation in the STS have been reported in patients with schizophrenia, it remains unclear whether other nodes of the "social brain network" are also atypical in patients with schizophrenia.

PURPOSE

We aimed to explore whether brain regions other than STS were involved during BM perception in patients with schizophrenia, using functional magnetic resonance imaging (fMRI).

METHODS AND PATIENTS

Seventeen patients with schizophrenia, and 17 age- and sex- matched healthy controls, underwent fMRI scanning during a one-back visual task, containing three experimental conditions: (1) BM, (2) scrambled motion (SM), and (3) static condition. We used one-sample t-tests to examine neural responses selective to BM versus SM within each group, and two-sample t-tests to directly compare neural patterns to BM versus SM in schizophrenics versus controls.

RESULTS

We found significant activation in the STS region when BM was contrasted with SM in both groups, with no significant difference between groups. On the contrary, significant activation in the medial prefrontal cortex (MPFC) and bilateral temporoparietal junction (TPJ) was found only in the control group. When we directly compared the two groups, the healthy controls showed significant greater activation in left MPFC and TPJ to BM versus SM than patients with schizophrenia.

CONCLUSION

Our findings suggest that patients with schizophrenia show normal activation to biologically and socially relevant motion stimuli in the STS, but atypical activation in other regions of the social brain network, specifically MPFC and TPJ. Moreover, these results were not due to atypical processing of motion, suggesting that patients with schizophrenia lack in the recruitment of neural circuits needed for the visual perception of social cognition.

Investigating the state-like and trait-like characters of social cognition in schizophrenia: a short term follow-up study

BACKGROUND AND OBJECTIVES

Controversial findings exist in the literature regarding the state- and trait-like characters of social cognition in schizophrenia. In order to explore the relationship of social cognition with symptom severity in the present study, Theory of mind (ToM) and emotion recognition were tested in an acute phase and later in a clinically stable phase in patients.

METHODS

ToM and emotion recognition abilities were examined by using the Reading the Mind in the Eyes Test (RMET) and the Ekman 60 Faces Test (FEEST) in 43 patients with schizophrenia and 41 healthy controls. Research diagnoses were based on SCID interviews. Symptom severity in patients was assessed by the Positive and Negative Syndrome Scale (PANSS).

RESULTS

ToM and emotion recognition deficits improved in the clinically stable phase compared to relapse, but were still found to be impaired compared to healthy controls. Negative symptom severity showed strong correlation with emotion recognition and ToM at both visits.

CONCLUSIONS

Both ToM and emotion recognition fluctuated together with symptom severity, which confirmed the "state-like" component of these abilities. Our results, taken together with the findings of previous investigations show that social cognition deficits in schizophrenia have both state-like and trait-like components.

Selective effect of neurocognition on different theory of mind domains in first-episode psychosis

The aim of this study was to investigate the influence of neurocognition on affective and cognitive theory of mind (ToM) tasks in early phases of psychosis. In a cross-sectional study of 60 first-episode schizophrenia/schizoaffective disorder patients, the implication of neurocognition in first- and second-order ToM stories, Hinting Task, and Reading the Mind in the Eyes Test (RMET) was analyzed. Regression models were used, controlling for clinical symptoms and antipsychotic dose. Spatial span backward (odds ratio [OR], 0.34; p = 0.01) and intrusions in the Rey Auditory Verbal Learning Test (OR, 4.86; p = 0.04) were the best factors to predict second-order ToM failure. Trail Making Test B (B = 0.01; p = 0.04) and negative symptoms (B = 0.09; p = 0.01) predicted Hinting task performance while Block design (B = 0.1; p = 0.04) was related to RMET outcome. Executive functions and clinical symptoms were related to ToM performance in first-episode schizophrenia patients, although different patterns of relationship were observed in each ToM task.

The Reading the Mind in the Eyes test: validation of a French version and exploration of cultural variations in a multi-ethnic city

INTRODUCTION

The first aim of our study was to validate the French version of the Reading the Mind in the Eyes test, a theory of mind test. The second aim was to test whether cultural differences modulate performance on this test.

METHODS

A total of 109 participants completed the original English version and 97 participants completed the French version. Another group of 30 participants completed the French version twice, one week apart.

RESULTS

We report a similar overall distribution of scores in both versions and no differences in the mean scores between them. However, 2 items in the French version did not collect a majority of responses, which differed from the results of the English version. Test-retest showed good stability of the French version. As expected, participants who do not speak French or English at home, and those born in Asia, performed worse than North American participants, and those who speak English or French at home.

CONCLUSIONS

We report a French version with acceptable validity and good stability. The cultural differences observed support the idea that Asian culture does not use theory of mind to explain people's behaviours as much as North American people do.

Theory of mind performance using a story comprehension task in bipolar mania compared to schizophrenia and healthy controls

INTRODUCTION

Theory of mind (ToM) refers to the ability to understand the mental state of self and others. There is limited research into this topic in bipolar disorder (BD), with no previous study examining ToM in a BD group within a psychotic manic phase.

METHODS

Twenty-eight psychotic manic BD patients were compared with 30 schizophrenia (SCZ) patients and 29 healthy controls (HC). Participants performed a ToM story comprehension task that compared ToM stories and non-ToM stories (which we relabelled non-ToM "semantic" stories). Performance was examined by answering comprehension questions.

RESULTS

Both patient groups were equally impaired on their scores for ToM stories (scores BD = 10/24, SCZ = 9/24, HC = 14/24, p < .001). Interestingly, both patient groups showed reduced performance on non-ToM semantic stories (scores BD = 12/24, SCZ = 9/24, HC = 15/24, p < .001); SCZ showed a larger deficit. Reduced ToM performance was correlated with delusion severity in the BD group only.

CONCLUSIONS

ToM performance was impaired in BD patients experiencing psychotic symptoms. Patient performance was also impaired on the control condition (i.e., non-ToM semantic stories) supporting an additional deficit in semantic processing.

Theory of mind impairments in patients with deficit schizophrenia

The deficit syndrome, a subgroup within schizophrenia, is characterized by enduring, idiopathic negative symptoms. Theory of mind (ToM), a domain of social cognition, is the ability of attributing mental states to ourselves and other people. ToM impairments have not been investigated earlier in deficit schizophrenia. The aim of the present study was to examine ToM differences between patients with deficit (SZ-D) and non-deficit schizophrenia (SZ-ND). Gender differences were also investigated, and based on the literature a better ToM performance was expected in female patients. The participants were 28 patients with SZ-ND, 30 patients with SZ-D, and 29 healthy control volunteers. The "Reading the Mind in the Eyes Test" was used to asses ToM deficits. Control subjects outperformed both patient groups, while there were no significant differences between the two schizophrenia subgroups. In female subjects, both controls and patients with SZ-ND performed significantly better than the SZ-D subgroup. In male subjects, controls performed significantly better than both patient groups. The "diminished emotional range" and the "curbing of interest" items of the Schedule for the Deficit Syndrome showed significant negative relationship with the ToM score. Our main finding is that female subjects with SZ-ND performed significantly better than female subjects with SZ-D.

An asymmetry of translational biological motion perception in schizophrenia

Background: Biological motion perception is served by a network of regions in the occipital, posterior temporal, and parietal lobe, overlapping areas of reduced cortical volume in schizophrenia. The atrophy in these regions is assumed to account for deficits in biological motion perception described in schizophrenia but it is unknown whether the asymmetry of atrophy found in previous studies has a perceptual correlate. Here we look for possible differences in sensitivity to leftward and rightward translation of point-light biological motion in data collected for a previous study and explore its underlying neurobiology using functional imaging.

Methods:n = 64 patients with schizophrenia and n = 64 controls performed a task requiring the detection of leftward or rightward biological motion using a standard psychophysical staircase procedure. six control subjects took part in the functional imaging experiment.

Results: We found a deficit of leftward but not rightward biological motion (leftward biological motion % accuracy patients = 57.9% ± 14.3; controls = 63.6% ± 11.3 p = 0.01; rightward biological motion patients = 62.7% ± 12.4; controls = 64.1% ± 11.7; p > 0.05). The deficit reflected differences in distribution of leftward and rightward accuracy bias in the two populations. Directional bias correlated with functional outcome as measured by the Role Functioning Scale in the patient group when co-varying for negative symptoms (r = -0.272, p = 0.016). Cortical regions with preferential activation for leftward or rightward translation were identified in both hemispheres suggesting the psychophysical findings could not be accounted for by selective atrophy or functional change in one hemisphere alone.

Conclusion: The findings point to translational direction as a novel functional probe to help understand the underlying neural mechanisms of wider cognitive dysfunction in schizophrenia.

Deficient biological motion perception in schizophrenia: results from a motion noise paradigm

Background: Schizophrenia patients exhibit deficient processing of perceptual and cognitive information. However, it is not well-understood how basic perceptual deficits contribute to higher level cognitive problems in this mental disorder. Perception of biological motion, a motion-based cognitive recognition task, relies on both basic visual motion processing and social cognitive processing, thus providing a useful paradigm to evaluate the potentially hierarchical relationship between these two levels of information processing.

Methods: In this study, we designed a biological motion paradigm in which basic visual motion signals were manipulated systematically by incorporating different levels of motion noise. We measured the performances of schizophrenia patients (n = 21) and healthy controls (n = 22) in this biological motion perception task, as well as in coherent motion detection, theory of mind, and a widely used biological motion recognition task.

Results: Schizophrenia patients performed the biological motion perception task with significantly lower accuracy than healthy controls when perceptual signals were moderately degraded by noise. A more substantial degradation of perceptual signals, through using additional noise, impaired biological motion perception in both groups. Performance levels on biological motion recognition, coherent motion detection and theory of mind tasks were also reduced in patients.

Conclusion: The results from the motion-noise biological motion paradigm indicate that in the presence of visual motion noise, the processing of biological motion information in schizophrenia is deficient. Combined with the results of poor basic visual motion perception (coherent motion task) and biological motion recognition, the association between basic motion signals and biological motion perception suggests a need to incorporate the improvement of visual motion perception in social cognitive remediation.

Theory of mind impairments in first-episode psychosis, individuals at ultra-high risk for psychosis and in first-degree relatives of schizophrenia: systematic review and meta-analysis

Theory of mind (ToM) deficit is a well-established feature of schizophrenia and has been suggested as a vulnerability marker of this disorder. However, as most of this evidence is based on studies in chronic patients, it is less clear whether ToM is impaired prior to or following the onset of a first-episode and whether it is evident in unaffected relatives of patients. In this meta-analysis, ToM performance of 3005 individuals with first-episode psychosis (FEP), individuals at ultra-high risk for psychosis (UHR) and unaffected relatives were compared with 1351 healthy controls. ToM was substantially impaired in first-episode psychosis (Cohen d=1.0) and this deficit was comparable to findings in chronic patients. ToM was also impaired in unaffected relatives (d=0.37) and UHR subjects (d=0.45) and performances of these groups were intermediate between FES and healthy controls. Severity of ToM deficits in unaffected relatives and UHR subjects was similar to other cognitive deficits observed in these groups. Longitudinal studies of clinical and genetic high-risk subjects are necessary to investigate the trajectory of development of ToM deficits in schizophrenia.

Social cognition impairments in Asperger syndrome and schizophrenia

Social cognition impairments are well described in both autism spectrum disorders, including Asperger syndrome (AS), and in schizophrenia spectrum disorders. However, little is known about whether there are differences between the two groups of disorders regarding this ability. The aim of this study was to compare social cognition abilities in AS and schizophrenia. Fifty-three individuals (26 men, 27 women) with a clinical diagnosis of AS, 36 (22 men, 14 women) with a clinical diagnosis of schizophrenic psychosis, and 50 non-clinical controls (19 men, 31 women) participated in the study. Clinical diagnoses were confirmed either by Structured Clinical Interview on DSM-IV diagnosis or the Diagnostic Interview for Social and Communication Disorders. Verbal ability was assessed using the Vocabulary subtest of the WAIS-III. Two social cognition instruments were used: Reading the Mind in the Eyes Test (Eyes Test) and the Animations Task. On the Eyes Test, patients with schizophrenia showed poorer results compared to non-clinical controls; however, no other group differences were seen. Both clinical groups scored significantly lower than the comparison group on the Animations Task. The AS group performed somewhat better than the schizophrenia group. Some differences were accounted for by gender effects. Implicit social cognition impairments appear to be at least as severe in schizophrenia as they are in AS. Possible gender differences have to be taken into account in future research on this topic.

A study of theory of mind in paranoid schizophrenia: a theory or many theories?

Social cognitive psychologists (Frith, 1992; Hardy-Baylé et al., 2003) sought to explain the social problems and clarify the clinical picture of schizophrenia by proposing a model that relates many of the symptoms to a problem of metarepresentation, i.e., theory of mind (ToM). Given the differences in clinical samples and results between studies, and considering the wide range of what is considered to constitute ToM, one must ask if there a core function, or is ToM multifaceted with dissociable facets? If, there are dissociable dimensions or facets, which are affected in patients with paranoid schizophrenia? To answer these questions, a group of 21 individuals diagnosed with paranoid schizophrenia and 29 non-clinical control subjects, were tested on a battery of five different measures of ToM. The results confirmed that there was little difference in specificity of three of the tests in distinguishing between the clinical and non-clinical group, but there were important differences in the shared variance between the tests. Further analyses hint at two dimensions although a single factor with the same variance and the same contributing weights in both groups could explain the results. The deficits related to the attribution of cognitive and affective states to others inferred from available verbal and non-verbal information. Further analyses revealed that incorrect attributions of mental states including the attribution of threatening intentions to others, non-interpretative responses and incomplete answers, depending on the test of ToM.

Mental state decoding abilities in young adults with borderline personality disorder traits

Previous studies have demonstrated that patients with borderline personality disorder (BPD) tend to misattribute malevolence to benign social stimuli, including facial expressions. Yet, facial emotion recognition studies examining those with BPD have yielded mixed results, with some studies showing impaired accuracy and others demonstrating enhanced accuracy in the recognition of emotions or mental states. The current study examined the ability to decode mental states from photographs of just the eye region of faces in a nonclinical sample of young adults who exhibited BPD traits (high BPD) compared with those who did not (low BPD). Group differences in mental state decoding ability depended on the valence of the stimuli. The high-BPD group performed better for negative stimuli compared with the low-BPD group, but did not perform significantly different from the low-BPD group for stimuli of neutral or positive valence. The high-BPD group also demonstrated a response bias for attributing negative mental states to facial stimuli. In addition, findings suggested that the group difference in accuracy for negative stimuli could not be explained by response bias, because the group difference in response bias for negative stimuli did not reach significance. These findings suggest that BPD traits may be associated with enhanced ability to detect negative emotions and a bias for attributing negative emotions to nonnegative social stimuli.

Theory of mind and paranoia in schizophrenia: a game theoretical investigation framework

INTRODUCTION. Ample evidence already shows that theory of mind (ToM) is impaired in people with schizophrenia. Our aim was to critically review this literature. METHOD. We completed a selected review of the research literature on ToM in schizophrenia. RESULTS. Gaps in ToM research were identified. A specific relationship between impaired ToM and paranoid delusions, although intuitively reasonable from a theoretical basis, has only been demonstrated in a few studies. Psychometric properties of ToM tasks employed in these studies may be a confounding factor in drawing conclusions about the relationship. Because most ToM measures have focused on the third-person perspective, participants are not actively interacting. The tasks fail to capture the cognitive demands faced by individuals in real-life situations, and, in effect, are not a direct measure of ToM. CONCLUSIONS. Potential research areas are discussed. Since game theoretical paradigms require the direct involvement of the first person and situate the participant's interpersonal reasoning within an interactive context, they provide more ecologically valid experimental platforms than conventional questionnaire measures to assess ToM in schizophrenia research.

Attentional guidance during visual search among patients with schizophrenia

The current study investigated visual guidance and saccadic selectivity during visual search among patients with schizophrenia (SCZ). Data from a previous study (Elahipanah, A., Christensen, B.K., & Reingold, E.M., 2008. Visual selective attention among persons with schizophrenia: The distractor ratio effect. Schizophr. Res. 105, 61-67.) suggested that visual guidance for the less frequent distractors in a conjunction search display (i.e., the distractor ratio effect) is intact among SCZ patients. The current study investigated the distractor ratio effect among SCZ patients when: 1) search is more demanding, and 2) search involves motion perception. In addition, eye tracking was employed to directly study saccadic selectivity for the different types of distractors. Twenty-eight SCZ patients receiving a single antipsychotic medication and 26 healthy control participants performed two conjunction search tasks: a within-dimension (i.e., colour × colour) search task; and a cross-dimension (i.e., motion × colour) search task. In each task the relative frequency of distractors was manipulated across 5 levels. Despite slower search times, patients' eye movement data indicated unimpaired visual guidance in both tasks. However, in the motion × colour conjunction search task, patients displayed disproportionate difficulty detecting the moving target when the majority of distractors were also moving. Results demonstrate that bottom-up attentional guidance is unimpaired among patients with SCZ; however, patients' impairment in motion discrimination impedes their ability to detect a moving target against noisy backgrounds.

Perceptual training strongly improves visual motion perception in schizophrenia

Schizophrenia patients exhibit perceptual and cognitive deficits, including in visual motion processing. Given that cognitive systems depend upon perceptual inputs, improving patients' perceptual abilities may be an effective means of cognitive intervention. In healthy people, motion perception can be enhanced through perceptual learning, but it is unknown whether this perceptual plasticity remains in schizophrenia patients. The present study examined the degree to which patients' performance on visual motion discrimination can be improved, using a perceptual learning procedure. While both schizophrenia patients and healthy controls showed decreased direction discrimination thresholds (improved performance) with training, the magnitude of the improvement was greater in patients (47% improvement) than in controls (21% improvement). Both groups also improved moderately but non-significantly on an untrained task-speed discrimination. The large perceptual training effect in patients on the trained task suggests that perceptual plasticity is robust in schizophrenia and can be applied to develop bottom-up behavioral interventions.

Reduced cortical thickness is associated with the glutamatergic regulatory gene risk variant DAOA Arg30Lys in schizophrenia

In light of current etiological concepts the glutamatergic system plays an essential role for the pathophysiology of the disorder, offering multiple options for new treatment strategies. The D-amino oxidase activator (DAOA) gene is closely connected to the glutamatergic system and its therapeutic and pathophysiological relevance for schizophrenia is therefore intensively debated. In a further step to shed light on the role of DAOA in schizophrenia, we aimed to investigate the association of the functional DAOA Arg30Lys (rs2391191) variant and cortical thickness in schizophrenia. Cortical thickness was computed by an automated surface-based technique (FreeSurfer) in 52 genotyped patients with schizophrenia and 42 healthy controls. Cortical thickness of the entire cortex was compared between risk carriers and non-risk carriers regarding the Arg30Lys polymorphism in patients and healthy controls on the basis of a node-by-node procedure and an automated clustering approach. Risk carriers with schizophrenia show significantly thinner cortex in two almost inversely arranged clusters on the left and right hemisphere comprising middle temporal, inferior parietal, and lateral occipital cortical areas. The clusters encompass an area of 1174 mm(2) (left) and 1156 mm(2) (right). No significant effect was observed in healthy controls.The finding of our study that the Arg30Lys risk variant is associated with a distinct cortical thinning provides new evidence for the pathophysiological impact of DAOA in schizophrenia. The affected areas are mostly confined to cortical regions with a crucial role in the ToM network and visual processing, which both can be influenced by glutamatergic modulation. Our finding thus underlines the importance of DAOA and related glutamatergic processes as a putative target for therapeutic interventions in schizophrenia.

Abnormal visual motion processing in schizophrenia: a review of research progress

Motion processing represents a perceptual domain in which dynamic visual information is encoded to support the perception of movement. Research over the last decade has found a variety of abnormalities in the processing of motion information in schizophrenia. The abnormalities span from discrimination of basic motion features (such as speed) to integration of spatially distributed motion signals (such as coherent motion). Motion processing involves visual signals across space and time and thus presents a special opportunity to examine how spatial and temporal information is integrated in the visual system. This article surveys the behavioral and neuroimaging studies that probe into the spatial integration of motion information in schizophrenia. An emerging theme from these studies points to an imbalanced regulation of spatial interaction processes as a potential mechanism mediating different levels of abnormal motion processing in schizophrenia. The synthesis of these mechanism-driven studies suggests that further investigation of the neural basis and functional consequences of this abnormal motion processing are needed in order to render a basic biomarker for assessment and intervention of cognitive dysfunction in this mental disorder.

Perception of biological motion in schizophrenia and healthy individuals: a behavioral and FMRI study

BACKGROUND

Anomalous visual perception is a common feature of schizophrenia plausibly associated with impaired social cognition that, in turn, could affect social behavior. Past research suggests impairment in biological motion perception in schizophrenia. Behavioral and functional magnetic resonance imaging (fMRI) experiments were conducted to verify the existence of this impairment, to clarify its perceptual basis, and to identify accompanying neural concomitants of those deficits.

METHODOLOGY/FINDINGS

In Experiment 1, we measured ability to detect biological motion portrayed by point-light animations embedded within masking noise. Experiment 2 measured discrimination accuracy for pairs of point-light biological motion sequences differing in the degree of perturbation of the kinematics portrayed in those sequences. Experiment 3 measured BOLD signals using event-related fMRI during a biological motion categorization task. Compared to healthy individuals, schizophrenia patients performed significantly worse on both the detection (Experiment 1) and discrimination (Experiment 2) tasks. Consistent with the behavioral results, the fMRI study revealed that healthy individuals exhibited strong activation to biological motion, but not to scrambled motion in the posterior portion of the superior temporal sulcus (STSp). Interestingly, strong STSp activation was also observed for scrambled or partially scrambled motion when the healthy participants perceived it as normal biological motion. On the other hand, STSp activation in schizophrenia patients was not selective to biological or scrambled motion.

CONCLUSION

Schizophrenia is accompanied by difficulties discriminating biological from non-biological motion, and associated with those difficulties are altered patterns of neural responses within brain area STSp. The perceptual deficits exhibited by schizophrenia patients may be an exaggerated manifestation of neural events within STSp associated with perceptual errors made by healthy observers on these same tasks. The present findings fit within the context of theories of delusion involving perceptual and cognitive processes.

Are theory of mind deficits in understanding intentions of others associated with persecutory delusions?

The purpose of this study was to investigate the association of the Theory of Mind ability to infer intentions of others and delusions in patients with schizophrenia-spectrum disorders. In a cross-sectional design, patients with acute persecutory delusions (PD) (n = 33), patients with remitted persecutory delusions (PD-rem) (n = 25), and non-clinical controls (n = 58) completed a movie task, in which they had to infer the characters' intentions and emotions and a false-belief task. Delusions were rated by observers and by the patients. Patients with PD were specifically impaired in the ability to infer intentions compared with patients with remitted delusions and controls. The ability to infer intentions predicted a significant amount of variance in delusions, even when executive functioning was controlled. Implications for models explaining the development and maintenance of delusions are discussed.

Subthalamic nucleus stimulation affects theory of mind network: a PET study in Parkinson's disease

Background

There appears to be an overlap between the limbic system, which is modulated by subthalamic nucleus (STN) deep brain stimulation (DBS) in Parkinson's disease (PD), and the brain network that mediates theory of mind (ToM). Accordingly, the aim of the present study was to investigate the effects of STN DBS on ToM of PD patients and to correlate ToM modifications with changes in glucose metabolism.

Methodology/Principal Findings

To this end, we conducted ¹⁸FDG-PET scans in 13 PD patients in pre- and post-STN DBS conditions and correlated changes in their glucose metabolism with modified performances on the Eyes test, a visual ToM task requiring them to describe thoughts or feelings conveyed by photographs of the eye region. Postoperative PD performances on this emotion recognition task were significantly worse than either preoperative PD performances or those of healthy controls (HC), whereas there was no significant difference between preoperative PD and HC. Conversely, PD patients in the postoperative condition performed within the normal range on the gender attribution task included in the Eyes test. As far as the metabolic results are concerned, there were correlations between decreased cerebral glucose metabolism and impaired ToM in several cortical areas: the bilateral cingulate gyrus (BA 31), right middle frontal gyrus (BA 8, 9 and 10), left middle frontal gyrus (BA 6), temporal lobe (fusiform gyrus, BA 20), bilateral parietal lobe (right BA 3 and right and left BA 7) and bilateral occipital lobe (BA 19). There were also correlations between increased cerebral glucose metabolism and impaired ToM in the left superior temporal gyrus (BA 22), left inferior frontal gyrus (BA 13 and BA 47) and right inferior frontal gyrus (BA 47). All these structures overlap with the brain network that mediates ToM.

Conclusion/Significance

These results seem to confirm that STN DBS hinders the ability to infer the mental states of others and modulates a distributed network known to subtend ToM.

Emotion processing and theory of mind in schizophrenia patients and their unaffected first-degree relatives

Previous studies have suggested that social cognition is affected in individuals with schizophrenia. The purpose of this study was to explore to what extent social cognition deficits are shared by unaffected first-degree relatives, and the nature of the relationship between performance in different paradigms of social cognition. 20 Schizophrenia patients (7 females, 31+/-10 years), 20 healthy age- and gender-matched individuals, 20 unaffected first-degree relatives of the schizophrenia patients (11 females, 50+/-20 years), and 20 healthy individuals matched for age and gender were recruited. Patients showed deficits in the detection of social Faux Pas (0.80+/-0.17 vs. controls: 0.94+/-0.09, p=0.025) and the correct identification of Theory of Mind stories (0.71+/-0.13 vs. controls: 0.82+/-0.12, p=0.038). Relatives performed poorly in the Faces Test (0.83+/-0.14 vs. controls: 0.9+/-0.08, p=0.048), the Reading the Mind in the Eyes Test (0.59+/-0.17 vs. controls: 0.71+/-0.14, p=0.046) and the detection of social Faux Pas (0.8+/-0.2 vs. controls: 0.93+/-0.09, p=0.024). Abnormalities were independent of age, years of education, and general cognitive performance in patients and their relatives. Performance in an Emotion Processing task (Faces Test) was correlated with performance in theory of mind tests in healthy individuals and relatives of patients with schizophrenia only. These results suggest that schizophrenia patients and their unaffected first-degree relatives display similar but nonidentical patterns of social cognition processing.

Theory of mind impairment: a distinct trait-marker for schizophrenia spectrum disorders and bipolar disorder?

OBJECTIVE

The aim of this study was to critically review the literature in order to determine if Theory of Mind (ToM) impairment can be considered a trait-marker for schizophrenia spectrum disorders and bipolar disorder (BD).

METHOD

After a thorough literature search, we reviewed the empirical studies investigating ToM impairments in remitted schizophrenia patients, first episode patients, subjects at high-risk (HR) for psychosis and first-degree relatives of schizophrenia patients. Studies investigating ToM impairment in other schizophrenia spectrum conditions, affective psychosis and BD were also reviewed.

RESULTS

ToM abnormalities exist at onset and continue throughout the course of schizophrenia, persist into remission, and while less severe, are apparent in HR populations. Mentalizing impairments are also observed in other forms of psychotic illness and BD.

CONCLUSION

Mentalizing impairment in schizophrenia spectrum disorders and BD might reflect underlying general cognitive deficits and residual symptom expression, rather than representing a specific trait-marker.

When doors of perception close: bottom-up models of disrupted cognition in schizophrenia

Schizophrenia is a major mental disorder that affects approximately 1% of the population worldwide. Cognitive deficits are a key feature of schizophrenia and a primary cause of long-term disability. Current neurophysiological models of schizophrenia focus on distributed brain dysfunction with bottom-up as well as top-down components. Bottom-up deficits in cognitive processing are driven by impairments in basic perceptual processes that localize to primary sensory brain regions. Within the auditory system, deficits are apparent in elemental sensory processing, such as tone matching following brief delay. Such deficits lead to impairments in higher-order processes such as phonological processing and auditory emotion recognition. Within the visual system, deficits are apparent in functioning of the magnocellular visual pathway, leading to higher-order deficits in processes such as perceptual closure, object recognition, and reading. In both auditory and visual systems, patterns of deficit are consistent with underlying impairment of brain N-methyl-d-aspartate receptor systems.

Theory of mind impairment in schizophrenia: meta-analysis

There is now substantial evidence for Theory of mind (ToM) impairment in schizophrenia. Despite this, we know little about how dynamic (state) variables and broad clinical, cognitive and medication characteristics moderate the precise magnitude of the observed ToM deficit during task performance. Meta-analyses were conducted using 36 studies that reported continuous data regarding ToM performances of schizophrenia patients and healthy control subjects. These 36 studies included 1,181 (67% male) patients with schizophrenia and 936 (58.3% male) healthy control subjects. Individual analyses were also conducted for the Hinting and the Eyes tasks. The effects of moderator variables were studied by both subgroup and meta-regression analyses. The effect sizes (Cohen's d) for overall ToM performance and the individual tasks were large (d=0.90-1.08). In "remitted" patients, the degree of ToM impairment was less pronounced than non-remitted patients (d=1.21) but it was still significant (d=0.80). Moreover, the distribution of effect sizes was more homogeneous for the individual tasks, especially in "remitted" patients. General intellectual deficits observed in schizophrenia patients contributed to their ToM impairment only in the remission phase of the illness. While state variables and task specific differences explain a large degree of the heterogeneity of the ToM findings observed in previous studies, the persistence of ToM deficits in "remitted" patients suggests there are trait related mentalising impairments in schizophrenia. Our review also suggests that future research should consider the potential moderating influence of IQ deficits on ToM performance in "remitted" patients, as well as the potential effects of residual symptoms.

The Reading the Mind in the Eyes Test: test-retest reliability of a Swedish version

INTRODUCTION

The Reading the Mind in the Eyes Test is a widely used facial affect recognition test. The present study aimed to provide Swedish nonpatient reference values, examine test-retest reliability, and to elucidate strengths and weaknesses of the instrument.

METHODS

A Swedish version of the test was completed by 158 university students. Fifty-eight participants completed the test twice, 3 weeks apart. The Bland Altman method was used to examine the test-retest reliability.

RESULTS

Distribution of responses of the 158 participants is detailed and compared with the English version. The limits of agreement was +/-4.3.

CONCLUSIONS

A test score variation in the range of +/-4 (out of 24 possible) is to be expected for the same individual. When the Reading the Mind in the Eyes Test is used, one has to take into account that an obtained test score must be regarded as an approximation.

Theory of mind and frontal lobe pathology in schizophrenia: a voxel-based morphometry study

Impaired ability to infer the mental states of others (theory of mind; ToM) is considered to be a key contributor to the poor social functioning of patients with schizophrenia. Although neuroimaging and lesion studies have provided empirical evidence for the neural basis of ToM ability, including the involvement of several prefrontal and temporal structures, the association between pathology of these structures and ToM impairment in schizophrenia patients is less well understood. To address this issue, we investigated structural brain abnormalities and ToM impairment in patients with schizophrenia, and examined the relationship between them. Twenty schizophrenia patients and 20 age-, sex- and education-matched healthy participants underwent magnetic resonance imaging (MRI) and were examined for ToM ability based on the revised version of the "Reading the Mind in the Eyes" (or Eyes) test [Baron-Cohen, S., Wheelwright, S., Hill, J., Raste, Y., Plumb, I., 2001. The 'Reading the Mind in the Eyes' test revised version: A study with normal adults, and adults with Asperger syndrome or high-functioning autism. J. Child Psychol. Psychiatry 42, 241-251]. Voxel-based morphometry (VBM) was performed to investigate regional brain alterations. Relative to normal controls, schizophrenia patients exhibited gray matter reductions in the dorsomedial prefrontal cortex (DMPFC), left ventrolateral prefrontal cortex (VLPFC), ventromedial prefrontal cortex (VMPFC), anterior cingulate cortex (ACC), right superior temporal gyrus (STG) and right insula. The patients performed poorly on the Eyes test. Importantly, poor performance on the Eyes test was found to be associated with gray matter reduction in the left VLPFC in the patient group. These results suggest that prefrontal cortical reduction, especially in the left VLPFC, is a key pathology underlying the difficulties faced by schizophrenia patients in inferring the mental states of others.

Impaired theory of mind in first-episode schizophrenia: comparison with community, university and depressed controls

First order theory of mind, as measured by the 'Reading the Mind in the Eyes Test' Revised, is impaired in schizophrenia. However, no study has investigated whether this occurs in first-episode schizophrenia. Also, it is unclear whether such a deficit is specific to schizophrenia, and whether convenience control samples, particularly undergraduate university students, represent valid comparison groups. This study investigated theory of mind ability, measured by the 'Reading the Mind in the Eyes Test' Revised, in a group of first-episode schizophrenia outpatients (n=13) and three control groups: outpatients with non-psychotic major depression (n=14), individuals from the general community (n=16) and from an undergraduate university course (n=27). The schizophrenia group exhibited significant theory of mind impairments compared to both non-psychiatric control groups but not the depression group. Unexpectedly, the depression group was not significantly impaired compared to the community control group, and the university control group exhibited superior theory of mind ability relative to all three groups. The findings indicate theory of mind deficits in first episode schizophrenia and support the implementation of theory of mind interventions in first-episode schizophrenia treatment programs. Results also indicate that community rather than university control groups represent more valid comparison groups in first-episode schizophrenia research.

Neuropsychological frontal impairments and negative symptoms in schizophrenia

Negative symptoms have been associated with frontal lobe dysfunction in schizophrenia. However, neuropsychological studies that evaluated the correlation between performance in tests sensitive to the dorsolateral prefrontal cortex (DLPFC) and negative symptoms have shown inconsistent results. Growing evidence has appeared that not only the DLPFC but other prefrontal regions could be involved in schizophrenia. We evaluated schizophrenic patients and healthy controls using three "frontal tests": the Wisconsin Card Sorting Test (WCST), the Iowa Gambling Task (GT) and a Theory of Mind test (Faux Pas), and studied the relationship between performance in these tests and negative symptomatology. Schizophrenic patients had worse performance than normal controls on the WCST, GT and Faux Pas test. The severity of the negative symptoms showed a moderate to high correlation with performance in the Faux Pas test. Our findings support the idea that different prefrontal regions could be affected in people with schizophrenia and that the damage to each of these regions could be, at least in part, independent of the damage to the others. Some negative symptoms could be associated with frontal medial cortex dysfunction.

Theory of mind in schizophrenia: meta-analysis

BACKGROUND

Mentalising impairment (an impaired ability to think about people in terms of their mental states) has frequently been associated with schizophrenia.

AIMS

To assess the magnitude of the deficit and analyse associated factors.

METHOD

Twenty-nine studies of mentalising in schizophrenia (combined n=1518), published between January 1993 and May 2006, were included to estimate overall effect size. Study descriptors predicted to influence effect size were analysed using weighted regression-analysis techniques. Separate analyses were performed for symptom subgroups and task types.

RESULTS

The estimated overall effect size was large and statistically significant (d=-1.255, P<0.0001) and was not significantly affected by sample characteristics. All symptom subgroups showed significant mentalising impairment, but participants with symptoms of disorganisation were significantly more impaired than the other subgroups (P<0.01).

CONCLUSIONS

This meta-analysis showed significant and stable mentalising impairment in schizophrenia. The finding that patients in remission are also impaired favours the notion that mentalising impairment represents a possible trait marker of schizophrenia.

Suspicious minds: The psychology of persecutory delusions

At least 10-15% of the general population regularly experience paranoid thoughts and persecutory delusions are a frequent symptom of psychosis. Persecutory ideation is a key topic for study. In this article the empirical literature on psychological processes associated with persecutory thinking in clinical and non-clinical populations is comprehensively reviewed. There is a large direct affective contribution to the experience. In particular, anxiety affects the content, distress and persistence of paranoia. In the majority of cases paranoia does not serve a defensive function, but instead builds on interpersonal concerns conscious to the person. However, affect alone is not sufficient to produce paranoid experiences. There is also evidence that anomalous internal experiences may be important in leading to odd thought content and that a jumping to conclusions reasoning bias is present in individuals with persecutory delusions. Theory of mind functioning has received particular research attention recently but the findings do not support a specific association with paranoia. The threat anticipation cognitive model of persecutory delusions is presented, in which persecutory delusions are hypothesised to arise from an interaction of emotional processes, anomalous experiences and reasoning biases. Ten key future research questions are identified, including the need for researchers to consider factors important to the different dimensions of delusional experience.

A role for the 'magnocellular advantage' in visual impairments in neurodevelopmental and psychiatric disorders

Evidence exists implicating abnormal visual information processing and visually driven attention in a number of neurodevelopmental and psychiatric disorders, suggesting that research into such disorders may benefit from a better understanding of more recent advances in visual system processing. A new integrated model of visual processing based on primate single cell and human electrophysiology may provide a framework, to understand how the visual system is involved, by implicating the magnocellular pathway's role in driving attentional mechanisms in higher-order cortical regions, what we term the 'magnocellular advantage'. Evidence is also presented demonstrating visual processing occurs considerably faster than previously assumed, and emphasising the importance of top-down feedback signals into primary visual cortex, as well as considering the possibility of lateral connections from dorsal to ventral visual areas. Such organisation is argued to be important for future research highlighting visual aspects of impairment in disorders as diverse as schizophrenia and autism.

Self-face recognition and theory of mind in patients with schizophrenia and first-degree relatives

OBJECTIVE

The hypothesized relationship between theory of mind (ToM) and self-face recognition as well as its potential genetic associations has not been previously explored in patients with schizophrenia and in first-degree relatives with schizotypal personality traits.

METHOD

Ten patients diagnosed with schizophrenia, 10 of their first-degree relatives and 10 healthy controls were included. To assess self-face recognition (SFR), participants were presented images of faces of themselves and others and asked to make rapid 'unfamiliar', 'familiar' and 'self' judgments. As a measure of ToM, subjects were administered the Revised Mind in the Eyes Test (MET [Baron-Cohen, S., Wheelwright, S., Hill, J., Raste, Y., and Plumb, I., 2001. The "Reading the Mind in the Eyes" Test revised version: a study with normal adults, and adults with Asperger syndrome or high-functioning autism. J Child Psychol Psychiatry 42(2), 241-251.]). Schizotypal characteristics in relatives and controls were assessed using a modified version of the Schizotypal Personality Questionnaire (SPQ [Raine, A., 1991. The SPQ: a scale for the assessment of schizotypal personality based on DSM-III-R criteria. Schizophrenia Bulletin 17(4), 555-564.]).

RESULTS

Patients took longer and were less accurate on the SFR task than their relatives who in turn performed worse than healthy controls. Specific ToM deficits in schizophrenia were replicated. There was a relationship between accuracy rates on the MET and SFR tasks. High levels of schizotypal traits such as social anxiety, constricted affect and no close friends were important for both tasks.

CONCLUSIONS

Face recognition deficits and ToM deficits in schizophrenia are apparent. The critical influence of high levels of select schizotypal traits is also highlighted. A deficit in relatives of schizophrenia patients raises the possibility that ToM and face recognition deficits may be candidate endophenotypes for schizophrenia. Support for the hypothesized link between ToM and face recognition is provided.