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

The associations of negative and disorganization symptoms with verbal fluency in schizophrenia: the mediation effect of processing speed and cognitive flexibility

BACKGROUND

Psychopathological symptoms appear important for cognitive functions in schizophrenia. Nevertheless, the factors and their impact on relationships between negative or disorganization symptoms and verbal fluency are still debatable. The preliminary objective of the study was to compare verbal fluency, including clustering and switching as cognitive strategies, executive functions, and processing speed between individuals with schizophrenia (SZ) and healthy controls (HC). The main aim of the study was to investigate mediation models and identify whether relationships between negative and disorganization symptoms and verbal fluency in schizophrenia are mediated by cognitive flexibility and processing speed.

METHODS

Semantic (animal and fruit) and phonemic (letter k and letter f) fluency tasks, the Berg Card Sorting Test (BCST), and the Color Trails Test (CTT) were administered in the SZ group (n = 108) and a matched HC group (n = 108). The Positive and Negative Syndrome Scale (PANSS) was applied to measure psychopathological symptoms in schizophrenia patients.

RESULTS

SZ produced fewer words, had larger cluster size, and fewer switches in semantic fluency than HC. Moreover, the SZ group had longer completion time in CTT 1 and CTT 2 and higher percent of perseverative and non-perseverative errors in BCST than HC. Three mediation models demonstrated good fit indices, suggesting that processing speed and cognitive flexibility were significant mediators for relationships between: (1) psychopathological symptoms and productivity or semantic clustering in animal fluency; (2) negative symptoms and productivity in semantic or phonemic fluency; and (3) disorganization symptoms and productivity in semantic fluency.

CONCLUSIONS

Individuals with schizophrenia are characterized by a specific performance profile on verbal fluency tasks. They manifest poor productivity and problems using cognitive strategies for semantic fluency. Referring to executive functioning, schizophrenia patients exhibit decreased cognitive flexibility, problem-solving, and formulating concepts, as well as slow processing speed. It was found that processing speed and cognitive flexibility may be understood as the neuropsychological mechanisms modifying the relationships between negative symptoms, disorganization symptoms, and semantic and phonemic fluency. Therefore, these results provide a foundation for including cognitive flexibility and processing speed in cognitive remediation for schizophrenia patients.

Association of Negative Symptoms of Schizophrenia Assessed by the BNSS and SNS Scales With Neuropsychological Performance: A Gender Effect

Objective: The relationship between negative symptoms and neurocognitive performance in schizophrenia is well documented, but the mechanism of these connections remains unclear. The study aims to measure the relationship between the results on the new scales for the assessment of negative symptoms such as Brief Negative Symptom Scale (BNSS) and Self-evaluation of Negative Symptoms (SNS), and the results of some neurocognition tests. The second aim is to assess a possible gender effect on these associations. Methods: The study included 80 patients (40 men, 40 women) with schizophrenia, aged 19-63 (mean 38 years), during the improvement period (total PANSS score <80, unchanged pharmacological treatment in the last 3 weeks). They were assessed using the BNSS, SNS, Personal and Social Performance (PSP) scales, and the tests for neuropsychological performance such as the Trail Making Test (TMT-A, TMT-B), Stroop Color-Word Interference Test, Verbal fluency tests (VFT), Category fluency test (CFT), and Digit Symbol Substitution Test (DSST). Results: Male patients obtained higher scores than females on some PANSS and BNSS items. No gender differences were observed for the SNS scale. Female patients scored better in the PSP and CFT. In male patients, a significant positive correlation between the intensity of negative symptoms measured by the BNSS and the results of PSP with the Trail Making Test was observed. In female patients, we found a positive correlation between the results of BNSS and PSP with the Stroop Color-Word Interference Test. Conclusion: The obtained results confirm the relationship between negative symptoms and neurocognition in schizophrenia patients. However, in male and female patients such association was observed for different cognitive domains. Further research is needed to explain the nature of these differences.

The Relationship between Negative Symptoms and Both Emotion Management and Non-social Cognition in Schizophrenia Spectrum Disorders

OBJECTIVE

There is ongoing debate regarding the relationship between clinical symptoms and cognition in schizophrenia spectrum disorders (SSD). The present study aimed to explore the potential relationships between symptoms, with an emphasis on negative symptoms, and social and non-social cognition.

METHOD

Hierarchical cluster analysis with k-means optimisation was conducted to characterise clinical subgroups using the Scale for the Assessment of Negative Symptoms and Scale for the Assessment of Positive Symptoms in n = 130 SSD participants. Emergent clusters were compared on the MATRICS Consensus Cognitive Battery, which measures non-social cognition and emotion management as well as demographic and clinical variables. Spearman's correlations were then used to investigate potential relationships between specific negative symptoms and emotion management and non-social cognition.

RESULTS

Four distinct clinical subgroups were identified: 1. high hallucinations, 2. mixed symptoms, 3. high negative symptoms, and 4. relatively asymptomatic. The high negative symptom subgroup was found to have significantly poorer emotion management than the high hallucination and relatively asymptomatic subgroups. No further differences between subgroups were observed. Correlation analyses revealed avolition-apathy and anhedonia-asociality were negatively correlated with emotion management, but not non-social cognition. Affective flattening and alogia were not associated with either emotion management or non-social cognition.

CONCLUSIONS

The present study identified associations between negative symptoms and emotion management within social cognition, but no domains of non-social cognition. This relationship may be specific to motivation, anhedonia and apathy, but not expressive deficits. This suggests that targeted interventions for social cognition may also result in parallel improvement in some specific negative symptoms.

Stability of Verbal Fluency in Outpatients with Schizophrenia

While it is well established that individuals with schizophrenia exhibit a wide range of neurocognitive deficits, there is significant heterogeneity in this regard. Impairments in verbal fluency appear to present consistently across most individuals with the illness. The present study examined the stability of verbal fluency abilities in chronic schizophrenia longitudinally. It was hypothesized that semantic but not phonemic verbal fluency performance would be stable over one year. Data was extracted from a larger study that followed 53 outpatients (70% male; mean age = 39.2 years) diagnosed with schizophrenia or schizoaffective disorder. At each testing interval (baseline, 6, and 12 months), the Brief Assessment of Cognition in Schizophrenia was administered, which included phonemic (i.e., F, S) and semantic (i.e., animals) verbal fluency tasks. No significant differences were found across time points for semantic and phonemic verbal fluency with respect to mean number of words generated, clustering, and switching. The findings provide evidence of stability in semantic and phonemic verbal fluency abilities in chronic schizophrenia. Moving forward, it would be valuable to examine verbal fluency performance longitudinally across multiple stages of illness (i.e., clinically high-risk to chronic schizophrenia).

Color Trails Test: A New Set of Data on Cognitive Flexibility and Processing Speed in Schizophrenia

BACKGROUND

Although schizophrenia patients have been reported to manifest deficits in cognitive flexibility and lower processing speed (measured with i.a., the Color Trails Test, CTT), there still remain a few matters that require further investigation. We have therefore formulated three research aims: 1) to examine the factor structure of CTT in schizophrenia patients and healthy controls, 2) to compare different CTT performance measures in the two groups, 3) to investigate the relationship between these measures and selected psychopathological symptoms in the patient group.

METHODS

Sixty-seven patients with paranoid schizophrenia and 67 healthy controls, matched for gender, age, number of years of education, and overall cognitive functioning underwent assessment of cognitive flexibility and processing speed with the CTT.

RESULTS

Factor analysis of CTT variables based on the principal component method revealed a four-factor solution in both groups. Compared with healthy controls, the patients performed poorer on CTT 1 time, CTT 2 time, 2-1 difference, prompts in CTT 2, and had higher regression factor scores for Factor 1 (reflecting the slower speed of perceptual tracking). Furthermore, significant links were found between some CTT measures, and negative and disorganization symptoms.

CONCLUSIONS

Schizophrenia patients exhibit problems with speed of perceptual tracking and executive processes dependent on processing speed. Our results may be useful for the development of neuropsychological diagnostic methods for schizophrenia patients. It seems that, compared to other CTT indices, CTT 1 time, CTT 2 time, and 2-1 difference are more appropriate measures of cognitive performance in schizophrenia patients.

The Relationship Between Cognitive Dysfunction and Symptom Dimensions Across Schizophrenia, Bipolar Disorder, and Major Depressive Disorder

Background: Cognitive dysfunction is considered a core feature among schizophrenia (SZ), bipolar disorder (BD), and major depressive disorder (MDD). Despite abundant literature comparing cognitive dysfunction among these disorders, the relationship between cognitive dysfunction and symptom dimensions remains unclear. The study aims are a) to identify the factor structure of the BPRS-18 and b) to examine the relationship between symptom domains and cognitive function across SZ, BD, and MDD. Methods: A total of 716 participants [262 with SZ, 104 with BD, 101 with MDD, and 249 healthy controls (HC)] were included in the study. One hundred eighty participants (59 with SZ, 23 with BD, 24 with MDD, and 74 HC) completed the MATRICS Consensus Cognitive Battery (MCCB), and 507 participants (85 with SZ, 89 with BD, 90 with MDD, and 243 HC) completed the Wisconsin Card Sorting Test (WCST). All patients completed the Brief Psychiatric Rating Scale (BPRS). Results: We identified five BPRS exploratory factor analysis (EFA) factors ("affective symptoms," "psychosis," "negative/disorganized symptoms," "activation," and "noncooperation") and found cognitive dysfunction in all of the participant groups with psychiatric disorders. Negative/disorganized symptoms were the most strongly associated with cognitive dysfunctions across SZ, BD, and MDD. Conclusions: Our findings suggest that cognitive dysfunction severity relates to the negative/disorganized symptom domain across SZ, BD, and MDD, and negative/disorganized symptoms may be an important target for effective cognitive remediation in SZ, BD, and MDD.

A diffusion weighted imaging study of basal ganglia in schizophrenia

OBJECTIVES

Several magnetic resonance imaging (MRI) studies provided evidence of selective brain abnormalities in schizophrenia, both in cortical and subcortical structures. Basal ganglia are of particular interest, given not only the high concentration of dopaminergic neurons and receptors, but also for their crucial role in cognitive functions, commonly impaired in schizophrenia. To date, very few studies explored basal ganglia using diffusion imaging, which is sensitive to microstructural organization in brain tissues. The aim of our study is to explore basal ganglia structures with diffusion imaging in a sizeable sample of patients affected by schizophrenia and healthy controls.

METHODS

We enrolled 52 subjects affected by schizophrenia according to DMS-IV-R criteria and 46 healthy controls. Diffusion weighted images were obtained using a 1.5 Tesla scanner and apparent diffusion coefficient (ADC) values were determined in axial and coronal sections at the level of basal ganglia.

RESULTS

Patients affected by schizophrenia showed a significantly higher ADC compared to healthy controls in the left anterior lenticular nucleus (F = 3.9, p = .05). A significant positive correlation between right anterior lenticular nucleus and psychotropic dosages was found (r = 0.4, p = .01).

CONCLUSIONS

Our study provides evidence of lenticular nucleus microstructure alterations in schizophrenia, potentially sustaining cognitive and motor deficits in schizophrenia. Key points The basal ganglia structures was explored with diffusion imaging in a sizeable sample of patients affected by schizophrenia and healthy controls. Patients affected by schizophrenia showed a significantly higher ADC compared to healthy controls in the left anterior lenticular nucleus. Our study provides evidence of lenticular nucleus microstructure alterations in schizophrenia, potentially sustaining cognitive and motor deficits in schizophrenia.

Theory of mind and schizophrenia in young and middle-aged patients: Influence of executive functions

Theory of Mind (ToM) is compromised in schizophrenia, and responsible for social disability. We aim to study the correlation between ToM deficits and Executive Functions (EF), using the Faux Pas Test (FPT) for ToM evaluation, Behavioral Assessment of the Dysexecutive Syndrome (BADS) and Wisconsin Card Sorting Test (WCST) for EF assessment. Two groups of patients with schizophrenia were included: 22 young (18-35 years-old) and 18 middle-aged (>50 years-old) Patients, compared to age-matched Controls. We found worst FPT performances in both groups of patients, but with a more generalized pattern of dysfunction in the middle-aged patient group. This group had worse EF scores than both controls and younger patients. The association of EF with FPT items was uneven. In young patients only empathy (Q6) remained significant after controlling for EF and level of education, while in middle-aged patients faux pas explanation (Q4), false belief (Q5) and total scores remained significant. In young patients only affective TOM was impaired. No correlation was found with clinical symptoms, nor age at onset of the disease. We conclude that ToM deficit arises early during the course of the illness (already present in young patients), increases in middle-aged patients, and relates only partially with EF.

[Preventing violence in schizophrenia with cognitive remediation]

OBJECTIVES

The association between schizophrenia and violence represents an important issue in psychiatry. Often highly publicized, violent acts raise the question of their detection, prevention, management and treatment. There is no single, direct and exclusive link between aggressiveness and the underlying psychiatric disorder. On the contrary, the processes underlying this violence are multiple and interlinked. In addition to static and dynamic risk factors, cognitive deficits play an important role in the genesis and maintenance of violent and aggressive behavior.

METHODS

Using recent data from the international literature and the main databases, we first clarify the role played by cognitive deficits in the violence of patients with schizophrenia. We then evaluate the place of psychosocial interventions such as cognitive remediation and social cognitive training in managing the violent and aggressive behavior of these patients.

RESULTS

Executive functions and working memory are the most studied neurocognitive functions in the field of violence in schizophrenia. Impulsivity, lack of cognitive flexibility, lack of adaptation and inhibition of automatic motor responses, and altered anger regulation may explain this relationship. Three main components of social cognition are associated with violent behaviors in schizophrenia: (1) the recognition of facial emotions through the inoperability of systems of "emotional monitoring", violent inhibition and recognition of informative facial zones; (2) the theory of the mind through the erroneous interpretation of the intentions of others; (3) the attributional style through the preferentially aggressive over interpretation of social situations and weak capacities of introspection. Overall, cognitive biases inhibit response in a socially acceptable manner and increase the risk of responding impulsively and aggressively to a stressful or provocative situation. In this context, we studied the place held by psychosocial interventions in the management of the violent and aggressive behaviors of these patients. Various cognitive remediation programs have shown their feasibility in people with schizophrenia and neurocognitive deficits with a history of violence as well as their effectiveness in reducing violence, mainly by reducing impulsivity. Similarly, specific programs dedicated to social cognitive training such as Social Cognition and Interaction Training (SCIT), Reasoning and Rehabilitation Mental Health Program (R&R2 MHP) and Metacognitive Training (MCT) have shown their positive impact on the control and reduction of global aggressive attitudes and on the numbers of physical and verbal aggressive incidents in schizophrenia. The improvement of social cognition would be achieved through the amendment of interpersonal relationships and social functioning. These interventions are effective at different stages of disease progression, in patients with varied profiles, on violent attitudes in general and on the number of verbal and physical attacks, whether for in-patients or out-patients. Beneficial effects can last up to 12months after termination of the study program. The interest of these interventions is preventive if the subject never entered in a violent register or curative in case of a personal history of violence. This type of care can be considered from a symptomatic point of view by limiting downstream the heavy consequences of such acts, but also etiologically by acting on one of the causes of violent behavior. Compliance with the eligibility criteria, carrying out a prior functional analysis and confirmation of the major impulsive part of the patient's violence are prerequisites for the use of these programs. Similarly, the early introduction of such therapies, their repetition over time and the integration of the patient into a comprehensive process of psychosocial rehabilitation will ensure the best chance of success.

CONCLUSIONS

Some cognitive impairments appear to have their place in the genesis, progression and maintenance of violent acts of individuals with schizophrenia. Their management thus opens new therapeutic perspectives such as cognitive remediation, still rarely used in this aim, to complement the action of the traditional care tools. However, further therapeutic trials are needed before considering cognitive remediation and social cognitive training as central care modalities in the therapeutic control of violence in schizophrenia.

Cognitive remediation and social cognitive training for violence in schizophrenia: a systematic review

A significant correlation exists between violence and schizophrenia (SCZ). Recent studies matched some cognitive deficits like strong risk factors for violence with interesting applications in terms of treatment. Our objective was to conduct a systematic review of the effectiveness of cognitive remediation (CR) and social cognitive training (SCT) in the management of violent and aggressive behaviors in SCZ.

METHODS

The electronic databases Pubmed, Web of Science, Cochrane Library and ScienceDirect were searched in, using combinations of terms relating to SCZ, CR and violence. Studies were selected and data were extracted using a PRISMA statement. Inclusion criteria were adults with SCZ and a documented collection of disruptive and violent behaviors, for whom researchers had used a CR or SCT program.

RESULTS

Eleven studies were identified, two related to non-specific CR intervention and nine to codified CR or SCT programs. Results showed that these programs had a positive impact on the control and reduction of global aggressive attitudes and physical assaults. Therapeutic targets were social cognition and executive functions through the improvement of interpersonal relationships and impulsivity feature respectively. Effectiveness was proved at various stages of the illness, in different types of patients and units, with effects persisting for up to 12 months after interruption of CR. Conclusions are limited by some methodological restrictions.

CONCLUSION

Although current evidences need to be completed with further randomized studies, CR and SCT appear to be promising approaches in the management of violence in SCZ.

Determinants of cerebral hemodynamics during the Trail Making Test in schizophrenia

Patients with schizophrenia show deficits in cognitive functioning, and studies on cerebral hemodynamics have revealed aberrant patterns of mean cerebral blood flow velocity (MFV), an equivalent of cerebral blood flow (CBF). Therefore, we carried out a controlled study that assessed MFV in schizophrenia during a well-known neuropsychological task, the Trail Making Test (TMT). We measured MFV in the middle cerebral arteries using functional transcranial Doppler sonography in 15 schizophrenia patients and 15 healthy subjects. In comparison to healthy subjects, patients performed poorer on the TMT-A and the TMT-B, and there was increased cerebral blood flow velocity during the TMT-B. A comparison of subgroups of patients and controls matched in performance on the TMT-B revealed that these patients still showed significantly increased cerebral blood flow velocity. Increased MFV in schizophrenia suggests specific alterations of cerebral hemodynamics during the Trail Making Test, Part B, which are not detectable during visuomotor activity, and which are independent of performance. These findings emphasize the pathophysiological importance of cognitive functioning in schizophrenia, but cast doubts whether performance in this particular test plays a relevant role for CBF abnormalities in schizophrenia.