Cognitive patterns in subtypes of schizophrenia.

AIM: Because of the heterogeneity of schizophrenia, this study researched different cognitive patterns in distinct subtypes of schizophrenic patients. METHODS: Thirty-five Diagnostic and Statistical Manual IV (DSM IV) schizophrenic patients and 35 healthy controls were included. Patients were categorized into deficit, disorganized and positive subtypes with the schedule for the deficit syndrome (SDS) and the positive and negative syndrome scale (PANSS). Executive/attentional functions were assessed with the modified card sorting test (MCST), a test of verbal fluency, the trail making test (TMT) and the Stroop color-word test (Stroop test). Episodic memory was explored through the California verbal learning test (CVLT). RESULTS: The positive subtype had some executive/attentional (fluency and Stroop tests) and mnesic performances in the normal range, suggesting the preservation of good cognitive skills. In contrast, the deficit and disorganized subtypes had major mnesic and executive/attentional dysfunctions compared to healthy subjects. The deficit subtype compared to the control group performed predominantly worse on the MCST and fluency, whereas the disorganized subtype had the lowest scores on the TMT and the Stroop test. CONCLUSION: This study showed distinct cognitive patterns in deficit, disorganized and positive patients in comparison with the controls, suggesting a heterogeneous cognitive dysfunction in schizophrenia.     

Executive/attentional cognitive functions in schizophrenic patients and their parents: a preliminary study.

The aim of this study was to determine whether executive/attentional cognitive performances could be considered as markers of vulnerability to schizophrenia.The Stroop Color Word and fluency tests were significantly impaired in schizophrenic patients and their parents compared to controls matched on age and sex while performances on Nelson's Modified Card Sorting Test and the Trail Making Test did not differ.The impairments on the Stroop and fluency could be considered as endophenotypic markers of schizophrenia.     

Executive dysfunctions as potential markers of familial vulnerability to bipolar disorder and schizophrenia

Attentional and executive impairments have been found both in patients with schizophrenia and in their unaffected first-degree relatives, suggesting that they might be considered as familial vulnerability markers. Several studies have shown that the performance of bipolar patients does not significantly differ from that of schizophrenic patients, so that executive and attentional deficits might not be specific to schizophrenia. In the present study, we aimed to identify executive dysfunctions in schizophrenia and bipolar disorder that might be vulnerability trait markers specific to one or common to both of these diseases. We assessed cognitive performance of euthymic bipolar and schizophrenic patients, their unaffected first-degree relatives and a healthy control group, using neuropsychological tasks to test different components of executive function: the Verbal Fluency Test, the Stroop Word Colour Test, the Wisconsin Card Sorting Test and the Trail Making Test. The two groups of patients and their unaffected relatives demonstrated disproportionately increased slowness on the Stroop test in comparison to the normal healthy group. Patients with schizophrenia performed poorly on all the tests in comparison to the normal healthy subjects, while no other impairment was observed in the bipolar patients and in the relatives of schizophrenic and bipolar patients. Enhanced susceptibility to interference and reduced inhibition could be transnosographical markers for a shared familial vulnerability common to schizophrenia and bipolar disorders.     

Neuropsychological correlates of schizophrenic syndromes in patients treated with atypical neuroleptics.

There is widespread evidence that schizophrenic symptomatology is best represented by three syndromes (positive, negative, disorganized). Both the disorganized and negative syndrome have been found to correlate with several neurocognitive dysfunctions. However, previous studies investigated samples predominantly treated with typical neuroleptics, which frequently induce parkinsonian symptoms that are hard to disentangle from primary negative symptoms and may have inflated correlations with neurocognition. A newly developed psychopathological instrument called the Positive and Negative and Disorganized Symptoms Scale (PANADSS) was evaluated in 60 schizophrenic patients. Forty-seven participants treated with atypical neuroleptics performed several neurocognitive tasks.A three-factor solution of schizophrenic symptomatology emerged. Negative symptomatology was associated with diminished creative verbal fluency and digit span backward, whereas disorganization was significantly correlated with impaired Stroop, WCST and Trail-Making Test B performance.Data suggest that disorganization is associated with tasks that demand executive functioning. Previous findings reporting correlations between negative symptomatology and neurocognition may have been confounded by the adverse consequences of typical neuroleptics.     

The behavioural assessment of the dysexecutive syndrome as a tool to assess executive functions in schizophrenia

Recent research into the cognitive dysfunctions in schizophrenia has focused on executive deficits. This study investigates performance of patients with schizophrenia on the recently developed Behavourial Assessment of the Dysexecutive Syndrome (BADS). Matched groups of 24 patients with schizophrenia and 17 healthy volunteers were administered the BADS, the Modified Card Sorting Test (MCST), the Tower of London (TOL), a test of general intelligence, and measures of daily functioning. Performance of the schizophrenic group was significantly below that of the control group on the BADS and the MCST, but not on the TOL. The BADS correlated weakly with the MCST. Both tests showed a modest correlation with daily functioning. The BADS appears to offer a useful contribution to the assessment of executive deficits in schizophrenia.     

Convergent validity and neuropsychological correlates of the schedule for the assessment of negative symptoms (SANS) attention subscale

Cognitive deficits have come to be viewed as a hallmark feature of schizophrenic illness. Although laboratory based assessment of patients' cognitive deficits has been well investigated, few studies to date have examined the utility of clinical ratings of cognitive symptoms using the Schedule for the Assessment of Negative Symptoms (SANS) attention subscale. In this report, we examined the convergence between clinical ratings of cognitive impairment using the SANS attention subscale and performance on a variety of neurocognitive tests designed to measure attentional impairment, as well as other cognitive constructs such as working memory and executive functioning. A total of 56 acute schizophrenic inpatients were clinically rated with the SANS and completed the Continuous Performance Test, Digit Span Distraction Test, Wisconsin Card Sorting Task, and the Trailmaking Test. A series of correlational and regression analyses were conducted to test the concurrent and discriminant validity of the SANS attention subscale. Performance measures of attention, but not working memory or executive functioning, were significantly correlated with and moderately predicted the severity of SANS rated inattention. Additionally, the attention subscale was discriminated from the other SANS negative symptom subscales in predicting a laboratory measure of attentional functioning. The SANS attention subscale demonstrated both concurrent and discriminant validity. These data indicate that attentional dysfunction in schizophrenia can be meaningfully rated and interpreted using the SANS.     

Neuropsychological and activity of daily living script performance in patients with positive or negative schizophrenia

Cognitive and psychiatric determinants of impairment of complex activities of daily living (ADLs) were investigated in 33 schizophrenic patients and 16 normal comparison subjects. The schizophrenic patients were cognitively impaired and were deficient in the ADL. However, the impairment of ADL could not be explained specifically by impairment of higher-order executive function or by negative symptoms: memory functions were more related to impairment of ADL and positive symptoms as much as the negative ones. Positive symptoms were significantly related to commissive errors in the ADL, whereas negative symptoms were nonsignificantly related to omissive errors. Negative symptoms were significantly more related to memory impairment than to impairment on measures of higher-order executive function (working memory). This investigation demonstrates that an ecologically oriented approach to test development and measurement of ADL is fruitful in understanding schizophrenia-especially if it is constrained by cognitive constructs compatible with the phenomenology of the disease.     

Neurocognitive changes and negative symptoms in schizophrenia

It is widely recognized that schizophrenic disorders are often associated with impairments of cognitive performance. More recently, disorders of higher cognitive control processes ("executive control functions") have captured the attention of researchers as they can considerably impair patients' abilities to live an independent life. Apart from that, considering the heterogeneity of schizophrenia, there have been attempts to relate psychopathological syndromes to changes in distinct cognitive domains. The present review selectively focuses on evidence associating negative symptoms in schizophrenia with deficient performance in specific executive domains. Neurobiological evidence points to biochemical, structural and functional abnormalities in the frontal cortex and associated fronto-subcortical circuits as a common basis of both schizophrenic negative symptoms and disorders of executive control. In a multitude of neuropsychological studies, an association between negative symptoms and problems in the domains of response inhibition, multitasking, cognitive flexibility, contextual updating, problem solving and verbal fluency has been reported. In some cases, however, the disorganization syndrome but not the negative syndrome has been linked with impaired behaviour in these domains. The inconsistencies might be partly due to the unsatisfactory differentiation between the two symptom complexes. Future research should furthermore consider a more precise differentiation between primary and secondary negative symptoms. Finally, the assessment of executive control functions should be both specific and ecologically valid.     

Executive deficits in chronic PTSD related to political violence

Twenty-two subjects with chronic PTSD were compared to 23 subjects with no diagnoses (NPD) on tests of executive functioning (EF) that are assumed to have clinical significance after exposure to political violence. METHOD: The three cognitive components of EF, intentionality, inhibition and executive memory [Burgess, P. W., Alderman, N., Evans, J., Emslie, H., Wilson, B. A. (1998). The ecological validity of tests of executive function. Journal of the International Neuropsychological Society, 4, 547-58], were measured using the Tower of London, Stroop Color-Word Test and Wisconsin Card Sorting Test (WCST), respectively. RESULTS: The PTSD group was impaired on tasks measuring automatic processing and executive memory. Executive memory problems were related to elevated posttraumatic symptoms, but the executive components intentionality and inhibition did not differentiate the groups. Arousal and intrusive symptoms had no impact on intentionality. CONCLUSION: Posttraumatic symptoms are related to automatic processing problems and impairment in executive memory. Observed dysfunctions in mental flexibility could have a negative impact on the cognitive processing of traumatic memory, thus preventing from recovery.     

Performance on the Modified Card Sorting Test and its relation to psychopathology in adolescents and young adults with 22q11.2 deletion syndrome

Background   Approximately one-third of individuals with 22q11.2 deletion syndrome (22q11DS), a common genetic disorder highly associated with intellectual disabilities, may develop schizophrenia, likely preceded by a mild to moderate cognitive decline.
Methods   We examined adolescents and young adults with 22q11DS for the presence of executive function deficits using a modified version of the Wisconsin Card Sorting Test (MCST) and assessed whether specific performances were associated with concurrent schizophrenia-prodrome symptoms. We also examined possible relationships between MCST performance and broader indices of psychopathology, including self-reported internalising and externalising behavioural symptoms.
Results   Participants with 22q11DS scored significantly below age-matched controls on seven out of nine MCST measures, and poorer MCST performance was associated with increased positive prodromal and internalising behavioural symptoms.
Conclusions   The schizophrenia-prodrome in 22q11DS involves executive dysfunction, and longitudinal investigation is necessary to examine if specific executive function impairments precedes or co-occurs with the emergence of behavioural psychopathology.     

精神分裂症患者大脑两半球功能协同异常研究

目的：探索精神分裂症患者大脑两半球功能协同异常。方法：对20例以阳性症状为主的男性精神分裂症患者和20名男性正常人进行对照,采用两耳分听技术分别测验大脑两半球在刺激驱动条件（自动加工）和指令驱动条件（控制加工）时的注意与执行功能。结果：在刺激驱动条件下,精神分裂症患者表现为两耳分听汉语单字词的左耳（右半球）优势,而正常人则为右耳（左半球）优势;在注意左耳或右耳时患者的被注意耳的成绩虽有明显提高,但对另一侧耳刺激信息加工的抑制能力与正常人相比明显减弱,差异显著。结论：精神分裂症患者两半球功能协同有障碍,其大脑功能一侧化异常,可能与此有关。     

The generalized pattern of neuropsychological deficits in outpatients with chronic schizophrenia with heterogeneous Wisconsin Card Sorting Test results

Forty schizophrenic outpatients and 40 normal subjects were assessed using extensive clinical (eg, Brief Psychiatric Rating Scale, Scale for the Assessment of Negative Symptoms and Scale for the Assessment of Positive Symptoms) and neuropsychological (extended Halstead-Reitan Battery) measures. The schizophrenic patients had multiple neuropsychological deficits on tests of complex conceptual reasoning, psychomotor speed, new learning and incidental memory, and both motor and sensory-perceptual abilities. Neuropsychological impairment correlated more strongly with negative than positive symptoms. Overall, the schizophrenic outpatients showed relatively modest increases in the number of perseverative responses on the Wisconsin Card Sorting Test of abstraction flexibility. A subgroup of these schizophrenic patients seemed to be particularly impaired on the Wisconsin Card Sorting Test. This pattern of results, in conjunction with previous studies, supports the idea that, while some schizophrenic patients may have fixed, frontally based dysfunctions, these dysfunctions may be most prominent, and even fixed, in deteriorated, kraepelinian patients. These data provide evidence for diffuse and far-reaching deficits in a majority of outpatients with chronic schizophrenia.     

精神分裂症患者认知功能损害与阴阳性症状的关系

目的：探讨精神分裂症认知功能损害与阴性、阳性症状的关系。方法:至73例入组的患者随机给予利培酮、氯氮平治疗12周,并于治疗前、后盲法评定Wisconsin卡片分类测验（WCST）,Wechsler记忆测验（WMS）,阴状症状评定量表（SANS）与阳性症状评定量表（SAPS）。结果：治疗前精神分裂症患者的阴性症状、阳性症状均与认知功能有显著相关。主要与执行功能相关;注意障碍与记忆相关。治疗后,仅SAPS中怪异行为得分与WCST的持续反应数、持续错误数显著相关。结论：精神分裂症的认知功能损害是原发性的,并不是在阳性、阴性症状基础上产生的。     

Executive functions in adolescents with schizotypal personality disorder

Adolescents meeting diagnostic criteria for schizotypal personality disorder (SPD) are presumed to be at risk for developing schizophrenia in adulthood, making them an important group for exploring the developmental trajectory of the disease. Deficits in executive functioning have been documented in schizophrenia patients and adults with SPD. The present study examined executive functions in adolescents with SPD. It was predicted that the SPD group would score below comparison groups (normals and adolescents with other disorders) on measures of executive function, and that those with greater 'negative' signs of SPD would show more pronounced performance deficits. Analyses revealed that the performance of the SPD subjects was impaired relative to the other groups on the modified Wisconsin Card Sorting Test (MCST), but not on the Tower of London or the Controlled Oral Word Association Test. Consistent with prediction, regression analyses indicated that MCST deficits were associated with greater negative signs of SPD, but not positive signs.     

氯丙嗪和氯氮平对未经系统治疗精神分裂症患者认知功能的影响

目的 比较典型和非典型抗精神病药对未经系统治疗的精神分裂症患者认知功能的影响.方法 将164例未经系统治疗的精神分裂症住院患者随机分为氯丙嗪组(83例)和氯氮平组(81例),进行双盲对照治疗研究.于治疗前和治疗第12周末各做1次韦氏成人智力量表(WAIS-R)、韦氏记忆量表(WMS)、铁槽铁钉测验、手指敲击试验、动作功能测验、手功能协调测验、连线测验A和B、威斯康星卡片分类测验(WCST)及言语流利性测验10项神经心理测查.结果 治疗第12周末,氯氮平组各项认知功能测查结果 均明显好于氯丙嗪组(P<0.05～0.01);在控制入组时测查的水平和可能的干扰因素(年龄、文化程度和治疗第12周末的阳性症状、阴性症状、药物副反应的程度)后,大部分检测指标两组间差异仍有显著性[氯丙嗪组和氯氮平组WAIS-R操作智商分别为(76.8±19.2)分和(90.5±16.9)分,WMS总分分别为(56.3±24.5)分和(75.4±21.9)分,完成连线测验B的时间分别为(213.9±97.4)s和(143.7±78.5)s,P均=0.000];氯氮平组各项认知功能指标均有所好转,而氯丙嗪组在16项认知功能指标中有7项恶化.结论 未经系统治疗的精神分裂症患者在第1次住院治疗时,氯氮平对其认知功能有改善作用,而氯丙嗪对认知功能的某些方面有损害.     

Processing of context information in schizophrenia: relation to clinical symptoms and WCST performance

Failure in contextual information processing has been hypothesized as being the single function responsible for several impairments in cognitive tasks and symptoms, through an involvement of the prefrontal cortex, in patients with schizophrenia. A variant of the Continuous Performance Test (CPT) designed specifically to elicit deficits in the processing of contextual information has been administered to 20 schizophrenic patients and 20 healthy controls. The relation to Wisconsin Card Sorting Test (WCST), relatively specific to prefrontal damage and executive dysfunctioning, and clinical status by using scales for the assessment of positive, negative symptoms and outcome has been investigated. The data show that multi-episode schizophrenic patients manifest inability to use contextual information to inhibit habitual response to an ambiguous stimulus and to maintain information across delay, without a general attention deficit. We also found a relationship between contextual reasoning and WCST unique errors, hallucinations, formal thought disorders, and outcome evaluation. Our results further support the hypothesis that the deficit of contextual reasoning could account for cognitive impairments and symptoms of patients with schizophrenia.     

Familial resemblance for executive functions in families of schizophrenic and bipolar patients

Executive dysfunctions are considered to be putative markers of familial/genetic vulnerability to both schizophrenia and bipolar disorder. However, familial resemblance must be demonstrated before executive functions are used as a potential endophenotype. The aim of this study was to investigate familial resemblance for executive functions in families of schizophrenic and bipolar subjects. We assessed executive functions by means of two tests - the Wisconsin Card Sorting Test (WCST) and the Trail Making Test (TMT) - in 351 subjects from five populations: schizophrenic patients, bipolar patients, a group of relatives for each patient group and controls. For both tests, cognitive assessment results were consistent with previous studies: schizophrenic patients showed the greatest impairment, followed by bipolar patients and then the two groups of relatives. In families of bipolar patients we observed familial resemblance for the WCST and part A and part B of the TMT. However, by contrast with the classical point of view, considering executive measures to be markers of genetic vulnerability to schizophrenia, we did not demonstrate familial resemblance for either of the two executive tests in families of schizophrenic patients. Thus, executive measures, as assessed by the WCST or the TMT, should not be used as endophenotypes in genetic studies of schizophrenia unless confounders are identified and their effects eliminated.     

Relationship of affect recognition with psychopathology and cognitive performance in schizophrenia.

The purpose of the present study was to explore the relationship between emotion perception and both psychopathology and cognitive functioning in a group of Greek patients with schizophrenia. Thirty-five patients with schizophrenia were assessed with computerized tests of emotion perception, using visual faces (Kinney's Affect Matching Test, KAMT), prosody (Affective Prosody Test, APT), and visual everyday scenarios (Fantie's Cartoon Test, FCT), as well as a facial recognition test (Kinney's Identity Matching Test, KIMT). The patients were also evaluated with the symptoms dimensions derived from the PANSS (positive, negative, cognitive, depression, and excitement) and a battery of neuropsychological tests measuring executive functions, attention, working memory, verbal and visual memory, visuospatial ability, and visual scanning/psychomotor speed. The three emotion perception and face recognition tests correlated significantly with each other. The KAMT was significantly related to the cognitive symptoms dimension of the PANSS and executive functions. The FCT was significantly related to level of education and attention. Finally, the APT was significantly related to the cognitive symptoms dimension, executive functions, and attention. Our findings regarding the significant relationships of affect perception, both facial and vocal, as well as in everyday scenarios, with several cognitive abilities support the notion that deficits in decoding affective information in schizophrenia could be attributed to impairment in more basic neurocognitive domains.     

Cognitive dysfunctions in medicated and unmedicated patients with recent-onset schizophrenia

Schizophrenia is associated with impairments in many cognitive domains on which the influence of antipsychotics, whether conventional or atypical, remains unclear. We conducted a study of recent-onset schizophrenic patients (DSM IV) that included unmedicated (n=19), and medicated (n=19) patients matched for age and IQ. Both groups of patients had comparably low extra-pyramidal symptoms (EPS). Cognitive tasks included attentional tasks (alertness and divided attention tests), a working memory task (a verbal n-back test) and the Wisconsin Card Sorting Test (WCST). After adjustment for the Total PANSS score, we found no significant difference between the two groups of patients in any of the cognitive tasks. When compared to a group of healthy controls (n=20) matched for IQ level, unmedicated patients performed significantly worse in all cognitive tasks, with significantly longer reaction times for alertness, divided attention and working memory. These results confirm the presence of cognitive impairments in attentional and executive functions in recent-onset patients whether or not they are medicated. There was no evidence that either conventional or atypical antipsychotics had an influence on patients when EPS were excluded. Altogether, our results further support the idea that cognitive deficits in schizophrenia are enduring features per se and cannot be considered as secondary to psychiatric symptoms or to the adverse effects of medication. In addition our results suggest that antipsychotics do not have a major effect on these impairments.     

Correlation between clinical syndromes and neuropsychological tasks in unmedicated patients with recent onset schizophrenia

The aim of this study is to circumscribe the cognitive deficits according to schizophrenic syndromes in a population of sub-acute untreated patients. We have studied the cross-sectional correlation between cognitive deficits and schizophrenic symptoms, in a group of 24 untreated patients (including 17 neuroleptic-naive patients) with recent onset of the disease. A task of alertness, a working memory (WM) test (including two levels of difficulty) and an abbreviated version of the Wisconsin Card Sorting Test (WCST) were selected. WM deficits and poor performance on the WCST were highly correlated with disorganized symptoms, modestly with the positive syndrome and not with the negative syndrome. Thus, disorganized symptoms, more than any other, appear to be related to the impairment of executive function and WM in recent onset unmedicated patients with schizophrenia.