Cognitive correlates of schizophrenia signs and symptoms: I. Verbal communication disturbances

The cognitive aspect of formal thought disorder and its relationship with global social functioning and the quality of life in schizophrenia

PURPOSE

It was expected that using a comprehensive scale like the Thought and Language Disorder Scale (TALD) for measurement of FTD would enable assessing its heterogeneity and its associations with cognitive impairment and functionality. This study has aimed to analyze the relationship between formal thought disorder (FTD) and cognitive functions, functionality, and quality of life in schizophrenia.

METHODS

This cross-sectional exploratory study included 46 clinical participants meeting the DSM-5 diagnostic criteria for schizophrenia and 35 healthy individuals as the control groups. Data were acquired by means of the Turkish language version of the TALD, the Positive and Negative Syndrome Scale, the Clinical Global Impression Scale, the Functioning Assessment Short Test, the Social Functioning Scale, the World Health Organization Quality of Life Instrument-Short Form, and a neuropsychological test battery on executive functions, working memory, verbal fluency, abstract thinking, and response inhibition. Correlation analyses were conducted to detect significant relationships.

RESULTS

The clinical group scored failures in all cognitive tests. The objective positive FTD was associated with deficits in executive functions and social functioning. The objective negative FTD was associated with poor performance in all cognitive domains, physical quality of life, and social and global functioning. The subjective negative FTD was negatively correlated with psychological quality of life.

CONCLUSION

This study demonstrated that objective FTD factors reflect different underlying cognitive deficits and correlate with different functioning domains. Significant correlation was determined between subjective negative FTD and psychological quality of life. Given the close relationship of FTD with functioning and quality of life, the FTD-related cognitive deficits should be the key treatment goal in schizophrenia.

Cognitive correlates of 'Formal Thought Disorder' in a non-clinical sample with elevated schizotypal traits

Different dimensions of formal thought disorder (FTD) are distinguished by different patterns of cognitive dysfunction in patients with schizophrenia; however, inconsistent findings may relate to patient-related confounds. To avoid these confounds, we examined relationships between FTD dimensions and cognitive domains in a non-clinical sample with attenuated schizophrenia-like traits, or schizotypal traits, on the Schizotypal Personality Questionnaire (N = 91). To our knowledge, no study has done this. FTD dimension scores were derived following principal component analysis of the Scale for the Assessment of Thought, Language and Communication (TLC dimensions: Disorganisation, Verbosity, Emptiness) and the Thought and Language Index (TLI dimensions: Negative, Idiosyncratic). The sample completed a comprehensive neuropsychological battery. Findings indicate that higher-order reasoning, executive function (set shift and generative ability) and language/semantic functioning are the primary drivers of FTD in our non-clinical sample with elevated schizotypal traits, in line with schizophrenia research. FTD may have shared aetiology along the schizophrenia spectrum.

Negative symptom configuration in first episode Schizophrenia: findings from the "Parma Early Psychosis" program

Purpose: Identifying distinct dimensions of negative symptoms in First Episode Schizophrenia (FES) might result in a better understanding and treatment of this invalidating symptomatology. Aim of this study was to examine negative symptom structure in FES patients using the Positive and Negative Syndrome Scale (PANSS).Materials and Methods: All 147 participants, aged 12-35 years, completed the PANSS and the Global Assessment of Functioning (GAF) scale. A principal component analysis with varimax rotation was performed to investigate PANSS negative symptom structure in the FES total sample.Results: A 2-factor model (i.e. "Expressive Deficits" and "Asociality" dimensions) was identified. Only "Expressive Deficits" domain had a significant negative correlation with baseline GAF score.Conclusions: This bipartite solution seems to be adequate to describe the phenomenological variety of negative symptoms experienced by FES individuals at the point of entry in early intervention services.

A transnosographic approach of negative symptoms pathophysiology in schizophrenia and depressive disorders

BACKGROUND

Negative Symptoms (blunted affect, alogia, anhedonia, avolition and asociality) are observed in schizophrenia but also in depressive disorders.

OBJECTIVE

To gather cognitive, neuroanatomical, neurofunctional and neurobiological knowledge of negative symptoms in studies on schizophrenia, depressive disorder, and transnosographic studies.

RESULTS

Blunted affect in schizophrenia is characterized by amygdala hyperactivation and frontal hypoactivation, also found in depressive disorder. Mirror neurons, may be related to blunted affect in schizophrenia. Alogia may be related to cognitive dysfunction and basal ganglia area impairments in schizophrenia. Data surrounding alogia in depressive disorder is scarce; wider speech deficits are often studied instead. Consummatory Anhedonia may be less affected than Anticipatory Anhedonia in schizophrenia. Anhedonia is associated with reward impairments and altered striatal functions in both diagnostics. Amotivation is associated with Corticostriatal Hypoactivation in both disorders. Anhedonia and amotivation are transnosographically associated with dopamine dysregulation. Asociality may be related to oxytocin.

CONCLUSION

Pathophysiological hypotheses are specific to each dimension of negative symptoms and overlap across diagnostic boundaries, possibly underpinning the observed clinical continuum.

Neurocognitive and linguistic correlates of positive and negative formal thought disorder: A meta-analysis

Executive dysfunction and language impairment are the most prominent neuropsychological models of formal thought disorder (FTD) in schizophrenia. However, available studies have provided contradictory findings regarding the accuracy of these models. Furthermore, specific neurocognitive underpinnings of positive FTD (PosFTD) and negative FTD (NegFTD) are not clear. Following the systematic review of schizophrenia studies, a random-effects meta-analysis of the relationship between FTD and neurocognition/language in schizophrenia was conducted in 52 reports including 2805 patients. Neurocognition was significantly associated with both PosFTD (r = -0.21, CI = -0.14 to -0.27) and NegFTD (r = -0.24, CI = -0.18 to -0.30). Both PosFTD (r = ranged from -0.18 to -0.27) and NegFTD (r = ranged from -0.19 to -0.23) were significantly correlated with verbal memory, visual memory, attention, and processing speed. In meta-analyses of executive functions, PosFTD was significantly associated with working memory (r = -0.21), planning (r = -0.19), and inhibition (r = -0.21) and NegFTD was significantly associated with planning (r = -0.27), fluency (r = -0.27), and working memory (r = -0.24). In meta-analyses of linguistic variables, PosFTD was associated with deficits in syntactic comprehension (r = -0.27) and semantic processing (r = -0.18). In contrast, NegFTD was associated only with semantic comprehension (r = -0.21). Both PosFTD and NegFTD were significantly associated with executive dysfunction, neurocognitive deficits and semantic dysfunction but syntactic deficits were more specific to PosFTD. There were also some distinct patterns of relationships between the pattern of executive dysfunction and types of FTD. Fluency deficit was associated more strongly with NegFTD and poor inhibition was more specifically related to PosFTD. Current findings suggest that neurocognitive and linguistic correlates of PosFTD and NegFTD might be partly different.

"Formal Thought Disorder" in a General-Community Sample With Elevated Schizotypal Traits

Different dimensions of formal thought disorder (FTD) are distinguished by different patterns of cognitive dysfunction and cortical variability in patients with schizophrenia; however, inconsistent findings may relate to patient-related confounds. Investigating FTD in nonpatient samples with elevated levels of schizotypal traits avoids these confounds, but its utility to FTD research is unknown. Thus, we performed principal components analysis (PCA) of FTD ratings using the Scale for the Assessment of Thought, Language, and Communication (TLC) and the Thought and Language Index (TLI) in a general-community sample with elevated schizotypal traits. Both scales showed "clinically elevated" FTD, particularly, the TLC. PCA described a three-component TLC solution ("disorganization," "verbosity," "emptiness") and a two-component TLI solution ("negative," "idiosyncratic"), generally consistent with schizophrenia research. TLC "disorganization" and "emptiness" were correlated with psychosis-like experiences. TLI "negative" was associated with lower general cognitive function, consistent with schizophrenia research. FTD may have shared etiology along the schizophrenia spectrum.

Evidence that communication impairment in schizophrenia is associated with generalized poor task performance

People with schizophrenia exhibit wide-ranging cognitive deficits, including slower processing speed and decreased cognitive control. Disorganized speech symptoms, such as communication impairment, have been associated with poor cognitive control task performance (e.g., goal maintenance and working memory). Whether communication impairment is associated with poorer performance on a broader range of non-cognitive control measures is unclear. In the current study, people with schizophrenia (n =51) and non-psychiatric controls (n =26) completed speech interviews allowing for reliable quantitative assessment of communication impairment. Participants also completed multiple goal maintenance and working memory tasks. In addition, we also examined (a) simple measures of processing speed involving highly automatic prepotent responses and (b) a non-cognitive control measure of general task performance. Schizophrenia communication impairment was significantly associated with poor performance in all cognitive domains, with the largest association found with processing speed (r_s =-0.52). Further, communication impairment was also associated with the non-cognitive control measure of poor general task performance (r_s =-0.43). In contrast, alogia, a negative speech symptom, and positive symptoms were less if at all related to cognitive task performance. Overall, this study suggests that communication impairment in schizophrenia may be associated with relatively generalized poor cognitive task performance.

Distinct Neuropsychological Correlates in Positive and Negative Formal Thought Disorder Syndromes: The Thought and Language Disorder Scale in Endogenous Psychoses

The correlation of formal thought disorder (FTD) symptoms and subsyndromes with neuropsychological dimensions is as yet unclear. Evidence for a dysexecutive syndrome and semantic access impairments has been discussed in positive FTD, albeit focusing mostly on patients with schizophrenia. We investigated the correlation of the full range of positive and negative as well as subjective and objective FTD with neuropsychological domains in different patient groups. Patients with ICD-10 schizophrenia (n = 51), depression (n = 51), and bipolar mania (n = 18), as well as healthy subjects (n = 60), were interviewed with the Rating Scale for the Assessment of Objective and Subjective Formal Thought and Language Disorder (TALD) and assessed using a multidimensional neuropsychological test battery (executive function, semantic and lexical verbal fluency, attention, working memory, and abstract thinking). Partial correlation analysis, controlling for age and word knowledge, revealed significant results for the objective positive FTD dimension and executive dysfunctions. Objective negative FTD was associated with deficits in lexico-semantic retrieval, as well as attention and working memory dysfunctions. The results suggest that different neuropsychological substrates correlate with the multidimensional and phenomenologically different FTD syndromes. FTD is a complex, multidimensional syndrome with a variety of neuropsychological impairments, which should be accounted for in future studies investigating the pathogenesis of FTD.

The current conceptualization of negative symptoms in schizophrenia

Negative symptoms have long been conceptualized as a core aspect of schizophrenia. They play a key role in the functional outcome of the disorder, and their management represents a significant unmet need. Improvements in definition, characterization, assessment instruments and experimental models are needed in order to foster research aimed at developing effective interventions. A consensus has recently been reached on the following aspects: a) five constructs should be considered as negative symptoms, i.e. blunted affect, alogia, anhedonia, asociality and avolition; b) for each construct, symptoms due to identifiable factors, such as medication effects, psychotic symptoms or depression, should be distinguished from those regarded as primary; c) the five constructs cluster in two factors, one including blunted affect and alogia and the other consisting of anhedonia, avolition and asociality. In this paper, for each construct, we report the current definition; highlight differences among the main assessment instruments; illustrate quantitative measures, if available, and their relationship with the evaluations based on rating scales; and describe correlates as well as experimental models. We conclude that: a) the assessment of the negative symptom dimension has recently improved, but even current expert consensus-based instruments diverge on several aspects; b) the use of objective measures might contribute to overcome uncertainties about the reliability of rating scales, but these measures require further investigation and validation; c) the boundaries with other illness components, in particular neurocognition and social cognition, are not well defined; and d) without further reducing the heterogeneity within the negative symptom dimension, attempts to develop successful interventions are likely to lead to great efforts paid back by small rewards.

The current conceptualization of negative symptoms in schizophrenia

Negative symptoms have long been conceptualized as a core aspect of schizophrenia. They play a key role in the functional outcome of the disorder, and their management represents a significant unmet need. Improvements in definition, characterization, assessment instruments and experimental models are needed in order to foster research aimed at developing effective interventions. A consensus has recently been reached on the following aspects: a) five constructs should be considered as negative symptoms, i.e. blunted affect, alogia, anhedonia, asociality and avolition; b) for each construct, symptoms due to identifiable factors, such as medication effects, psychotic symptoms or depression, should be distinguished from those regarded as primary; c) the five constructs cluster in two factors, one including blunted affect and alogia and the other consisting of anhedonia, avolition and asociality. In this paper, for each construct, we report the current definition; highlight differences among the main assessment instruments; illustrate quantitative measures, if available, and their relationship with the evaluations based on rating scales; and describe correlates as well as experimental models. We conclude that: a) the assessment of the negative symptom dimension has recently improved, but even current expert consensus-based instruments diverge on several aspects; b) the use of objective measures might contribute to overcome uncertainties about the reliability of rating scales, but these measures require further investigation and validation; c) the boundaries with other illness components, in particular neurocognition and social cognition, are not well defined; and d) without further reducing the heterogeneity within the negative symptom dimension, attempts to develop successful interventions are likely to lead to great efforts paid back by small rewards.

Using poverty of speech as a case study to explore the overlap between negative symptoms and cognitive dysfunction

BACKGROUND

Negative symptoms and cognitive impairment are both regarded as important prognostic markers in schizophrenia. Although these two domains are viewed as distinct and separable, conceptual overlap exists. We sought to illustrate this overlap using speech deficits among patients with schizophrenia.

METHOD

Reductions in verbal output were rated by a clinician following an interview, and these ratings were taken to represent negative symptoms (i.e., alogia). Patients were also asked to recount words from specific categories in a standardized manner, and the number of words was recorded as per standard protocol for verbal fluency tests. These scores were taken to represent cognitive impairment. The cross-sectional and longitudinal relationships between these two variables were then examined.

RESULTS

Patients with more severe alogia produced significantly less words on the verbal fluency tests. This relationship was stronger than that observed with other negative symptoms, and also held after controlling for a number of sociodemographic and clinical variables (e.g., severity of illness). Prospective increases in the number of words produced during the verbal fluency test were associated with improvements in clinical alogia ratings, a longitudinal relationship that was not observed with other negative symptoms.

CONCLUSIONS

Some negative symptoms are conceptually related and therefore not fully distinct from cognitive impairments. Here, we demonstrate that clinical ratings of alogia and words produced during a cognitive test are tapping into a similar construct. Whether a specific deficit is classified as a negative versus cognitive symptom may be matter of semantics rather than reflective of divisible underlying processes.

The negative syndrome of schizophrenia: three -underlying components are better than two

AIMS

To analyse the underlying structure of the negative syndrome of schizophrenia as it is represented in the Brief Negative Symptom Scale.

METHODS

Cross-sectional, multicentre study, employing data from 190 evaluations.

STATISTICS

Exploratory factor analysis using the principal component analysis method.

RESULTS

The three-component solution explained 77.4% of the total variance. Pearson correlation coefficients between components were: 1-2=-0.494, 1-3=-0.117, and 2-3=0.179.

CONCLUSION

Our solution favours a three-component structure of the negative syndrome, consisting of: external world (anhedonia and asociality), inner world (avolition and blunted affect), and alogia, with the latter only marginally related to the two former components.

Examination of affective and cognitive interference in schizophrenia and relation to symptoms

The nature of emotion deficits in schizophrenia and anhedonia is still unclear, and understanding the nature of these deficits could help improve treatment of chronic symptoms and functional disability. An important mechanism in emotional functioning is attention to affective information. People with schizophrenia (n = 48) and a nonpsychiatric comparison group (n = 28) completed an affective interference task, a task used to assess attention to affective information. Given that the affective interference task also involves prepotent response inhibition, participants also completed a very similar, but nonaffective, cognitive interference task that involves prepotent inhibition but does not require attention to affective information. Results revealed that people with schizophrenia exhibited decreased affective interference on trials with a shorter length of time between the onset of the cue and onset of the target but increased cognitive interference at all time lengths between the cue and target onsets used in the study. In addition, decreased affective interference was associated with increased anhedonia and increased reports of wanting to ignore positive emotions. In contrast, increased cognitive interference was associated with increased communication disturbances and alogia. Overall, these results suggest that there may be a decrease in attention to affective information in schizophrenia and that affective interference is related to anhedonia. At the same time, these results provide further evidence of cognitive control prepotent inhibition deficits in schizophrenia, which are related to communication disturbances and alogia.

The nature and extent of working memory dysfunction in schizophrenia

This study aimed to examine verbal and visual-spatial working memory (WM) dysfunction in patients with schizophrenia. We compared 60 patients with schizophrenia with 57 healthy controls (matched for age, educational level, and IQ) on three WM tasks. Patients with schizophrenia performed significantly more poorly than healthy controls on verbal, visual, and spatial WM tests. Moreover, WM deficits were inversely associated with both the positive and negative symptoms of the patients. Taken together, these findings suggest that there are pervasive WM impairments in patients with schizophrenia. In addition, clinical features may play a significant role in the expression of WM deficits.

Semantics, pragmatics, and formal thought disorders in people with schizophrenia

BACKGROUND

The aim of this study was to analyze how formal thought disorders (FTD) affect semantics and pragmatics in patients with schizophrenia.

METHODS

The sample comprised subjects with schizophrenia (n = 102) who met the criteria for the disorder according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition Text Revision. In the research process, the following scales were used: Positive and Negative Syndrome Scale (PANSS) for psychopathology measurements; the Scale for the Assessment of Thought, Language, and Communication (TLC) for FTD, Word Accentuation Test (WAT), System for the Behavioral Evaluation of Social Skills (SECHS), the pragmatics section of the Objective Criteria Language Battery (BLOC-SR) and the verbal sections of the Wechsler Adults Intelligence Scale (WAIS) III, for assessment of semantics and pragmatics.

RESULTS

The results in the semantics and pragmatics sections were inferior to the average values obtained in the general population. Our data demonstrated that the more serious the FTD, the worse the performances in the Verbal-WAIS tests (particularly in its vocabulary, similarities, and comprehension sections), SECHS, and BLOC-SR, indicating that FTD affects semantics and pragmatics, although the results of the WAT indicated good premorbid language skills.

CONCLUSION

The principal conclusion we can draw from this study is the evidence that in schizophrenia the superior level of language structure seems to be compromised, and that this level is related to semantics and pragmatics; when there is an alteration in this level, symptoms of FTD appear, with a wide-ranging relationship between both language and FTD. The second conclusion is that the subject's language is affected by the disorder and rules out the possibility of a previous verbal impairment.

Alogia and formal thought disorder: differential patterns of verbal fluency task performance

BACKGROUND

There is evidence that alogia and formal thought disorder (FTD), two prominent speech symptoms in schizophrenia, are associated with different patterns of verbal fluency task deficits. Verbal fluency is thought to involve several cognitive mechanisms, including controlled retrieval, semantic memory, and context processing.

METHODS

The current research examined whether alogia and FTD were associated with different patterns of verbal fluency performance and whether these patterns of verbal fluency performance would implicate deficits in controlled retrieval, semantic memory, or context processing. In the current research, 34 people with schizophrenia completed letter and category fluency tasks and detailed ratings of alogia and FTD symptoms were made from typed transcripts.

RESULTS

Overall, alogia was associated with increased response latency between each word on the category fluency task, suggesting an association between alogia and poor controlled retrieval. In contrast, FTD was associated with a decreased proportion of semantically-related words on letter fluency, suggesting an association between FTD and poor context processing.

CONCLUSIONS

Alogia and FTD appear to be associated with unique patterns of fluency performance, implicating separate cognitive mechanisms.

Using computational patients to evaluate illness mechanisms in schizophrenia

BACKGROUND

Various malfunctions involving working memory, semantics, prediction error, and dopamine neuromodulation have been hypothesized to cause disorganized speech and delusions in schizophrenia. Computational models may provide insights into why some mechanisms are unlikely, suggest alternative mechanisms, and tie together explanations of seemingly disparate symptoms and experimental findings.

METHODS

Eight corresponding illness mechanisms were simulated in DISCERN, an artificial neural network model of narrative understanding and recall. For this study, DISCERN learned sets of autobiographical and impersonal crime stories with associated emotion coding. In addition, 20 healthy control subjects and 37 patients with schizophrenia or schizoaffective disorder matched for age, gender, and parental education were studied using a delayed story recall task. A goodness-of-fit analysis was performed to determine the mechanism best reproducing narrative breakdown profiles generated by healthy control subjects and patients with schizophrenia. Evidence of delusion-like narratives was sought in simulations best matching the narrative breakdown profile of patients.

RESULTS

All mechanisms were equivalent in matching the narrative breakdown profile of healthy control subjects. However, exaggerated prediction-error signaling during consolidation of episodic memories, termed hyperlearning, was statistically superior to other mechanisms in matching the narrative breakdown profile of patients. These simulations also systematically confused autobiographical agents with impersonal crime story agents to model fixed, self-referential delusions.

CONCLUSIONS

Findings suggest that exaggerated prediction-error signaling in schizophrenia intermingles and corrupts narrative memories when incorporated into long-term storage, thereby disrupting narrative language and producing fixed delusional narratives. If further validated by clinical studies, these computational patients could provide a platform for developing and testing novel treatments.

Glutamatergic model psychoses: prediction error, learning, and inference

Modulating glutamatergic neurotransmission induces alterations in conscious experience that mimic the symptoms of early psychotic illness. We review studies that use intravenous administration of ketamine, focusing on interindividual variability in the profundity of the ketamine experience. We will consider this individual variability within a hypothetical model of brain and cognitive function centered upon learning and inference. Within this model, the brains, neural systems, and even single neurons specify expectations about their inputs and responding to violations of those expectations with new learning that renders future inputs more predictable. We argue that ketamine temporarily deranges this ability by perturbing both the ways in which prior expectations are specified and the ways in which expectancy violations are signaled. We suggest that the former effect is predominantly mediated by NMDA blockade and the latter by augmented and inappropriate feedforward glutamatergic signaling. We suggest that the observed interindividual variability emerges from individual differences in neural circuits that normally underpin the learning and inference processes described. The exact source for that variability is uncertain, although it is likely to arise not only from genetic variation but also from subjects' previous experiences and prior learning. Furthermore, we argue that chronic, unlike acute, NMDA blockade alters the specification of expectancies more profoundly and permanently. Scrutinizing individual differences in the effects of acute and chronic ketamine administration in the context of the Bayesian brain model may generate new insights about the symptoms of psychosis; their underlying cognitive processes and neurocircuitry.

Action and object naming in schizophrenia

Patients with schizophrenia demonstrate impaired action verbal fluency, but no study has examined verb-noun differences using picture naming. The present study compared object and action naming in 20 adult patients diagnosed with schizophrenia (DSM-IV-TR, Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition, Text Revision; American Psychiatric Association, 2000) criteria, and 20 demographically matched healthy controls, using pictures. Overall, schizophrenic patients showed poorer naming than controls on all measures of object and action lexical semantic access and retrieval despite normal comprehension for action and object names. Results further indicated that action names were significantly more difficult to retrieve than object names in schizophrenic patients. The absence of dissociation in comprehension of action and object names but semantic errors in naming both classes suggests intact conceptual-semantic stores among middle-aged community-dwelling outpatients with schizophrenia but difficulties mapping semantics onto the lexicon. Action-naming impairments can arise from both semantic and postsemantic origins in schizophrenia. These results have implications for the neurobiology of language given the association between both schizophrenia and verb processing and frontal damage. Moreover, the issue being addressed is important for a cognitive characterization of schizophrenia and for an understanding of the representations of action and object names in the brain.

Verbal fluency, semantics, context and symptom complexes in schizophrenia

Lexical-semantic access and retrieval was examined in 15 adults diagnosed with schizophrenia and matched controls. This study extends the literature through the inclusion of multiple examinations of lexical-semantic production within the same patient group and through correlating performance on these tasks with various positive and negative clinical symptoms. On tasks of verbal fluency, meaning generation, sentence production using contextual information and confrontation naming, participants with schizophrenia made significantly more semantic errors on naming tasks; produced fewer meanings for homophones; produced fewer items on semantic, phonological, cued and switching fluency tasks; and produced more errors on sentence production tasks when compared to healthy controls. Significant correlations were also observed between ratings of psychomotor poverty and measures of semantic production and mental inflexibility. This study has provided additional evidence for deficits in lexical-semantic retrieval which are not due to underlying semantic store degradation, do not involve phonological based retrieval, and at the level of sentence generation appear to vary as a function of the contextual constraints provided.

CNTRICS final task selection: working memory

The third meeting of the Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia (CNTRICS) was focused on selecting promising measures for each of the cognitive constructs selected in the first CNTRICS meeting. In the domain of working memory, the 2 constructs of interest were goal maintenance and interference control. CNTRICS received 3 task nominations for each of these constructs, and the breakout group for working memory evaluated the degree to which each of these tasks met prespecified criteria. For goal maintenance, the breakout group for working memory recommended the AX-Continuous Performance Task/Dot Pattern Expectancy task for translation for use in clinical trial contexts in schizophrenia research. For interference control, the breakout group recommended the recent probes and operation/symmetry span tasks for translation for use in clinical trials. This article describes the ways in which each of these tasks met the criteria used by the breakout group to recommend tasks for further development.

Distinct conflict resolution deficits related to different facets of Schizophrenia

An important issue in understanding the nature of conflict processing is whether it is a unitary or multidimensional construct. One way to examine this is to study whether people with impaired conflict processing exhibit a general pattern of deficits or whether they exhibit impairments in distinct aspects of conflict processing. One group who might exhibit conflict deficits are people with schizophrenia. Schizophrenia is a heterogeneous disorder, with one way to break down the heterogeneity of schizophrenia is to examine specific symptoms. Previous research has found that specific symptoms of schizophrenia are associated with specific deficits in conflict processing. In particular, disorganization is associated with increased response conflict, alogia is associated with increased retrieval conflict, and anhedonia is associated with increased emotional conflict. Moreover, there is evidence that different types of conflict processing are unassociated with each other. This evidence suggests that conflict processing is a multidimensional construct and that different aspects of schizophrenia are associated with impairments in processing different types of conflict.

Cognitive correlates of schizophrenia signs and symptoms: III. Hallucinations and delusions

We examined the cognitive correlates of hallucinations and delusions in 47 schizophrenia spectrum individuals. Hallucinations were significantly negatively correlated with performance on episodic memory tasks, and were not significantly associated with performance on tasks measuring fluency or concentration/attention. Although hallucinations were more strongly associated with performance on verbal than non-verbal memory tasks, the difference was not statistically significant. There was also a trend for hallucinations to be associated with poorer performance on working memory tasks, though this association was eliminated when episodic memory performance was taken into account. Delusions were not significantly associated with any of the cognitive measures.

Cognitive correlates of schizophrenia signs and symptoms: II. Emotional disturbances

We examined the cognitive and motor correlates of emotional disturbances in 47 schizophrenia spectrum individuals. Neither affective flattening nor anhedonia was significantly associated with tasks measuring working memory or attention/concentration, or with overall performance on tasks measuring fluency or episodic memory. In contrast, as expected, emotional disturbances were associated with patterns of hemispheric lateralization. Affective flattening and anhedonia were both associated with episodic memory laterality and there were similar trends with motor laterality. Anhedonia was also associated with medication motor side effects.