Cognitive functioning and positive and negative symptoms in schizophrenia

The present study examined schizophrenics' performance on a variety of cognitive measures in order to explore the relationship between schizophrenic symptoms and cognitive performance. The Wechsler Adult Intelligence Scale and a battery of neuropsychological tests, developed at the Montreal Neurological Institute, were administered to 38 acutely ill, hospitalized schizophrenics. Patients were diagnosed using DSM III criteria. Negative symptoms were assessed with the SANS and positive symptoms with the SAPS. Both the cognitive tests and the symptom rating scales were re-administered to this sample at a 6 month follow-up period. Analyses revealed that, at both time periods cognitive deficits were more likely to be associated with high negative symptom ratings than with positive symptoms. Only certain tests showed significant improvement at the follow-up period. Furthermore, improved cognitive functioning was related to an improvement in positive, but not negative, symptoms.     

Kraepelinian subtype and deficit syndrome in chronic schizophrenia

The present study examined the clinical overlap between the Kraepelinian and deficit subtypes of schizophrenia. A total of 103 patients with schizophrenia were divided into four groups on the basis of the presence or absence of the two classifications, and the demographic and clinical characteristics of the groups were statistically compared. There was a significant overlap of Kraepelinian and deficit status, but nevertheless the retention of both classifications appears to be justified.     

Cognitive deficit in schizophrenia and its neurochemical basis

Cognitive impairment is a central feature of schizophrenia and has been correlated with negative symptoms and impaired social functioning. There is a growing body of data suggesting that the so-called atypical antipsychotic drugs (e.g. clozapine, risperidone, and olanzapine) are better at enhancing cognitive function than traditional neuroleptics. Preclinical studies of information processing using a pre-pulse inhibition model show that the mechanism of action of both olanzapine and clozapine for cognitive enhancement may involve glutamatergic/N-methyl-D-aspartate (NMDA) antagonism. Using positron emission tomography, we have described the metabolic and neurochemical correlates of cognitive impairment induced by glutamatergic/NMDA antagonism. A better understanding of the underlying causes of cognitive impairment may contribute to elucidating the pathophysiology of schizophrenia and the development of more efficacious treatments for this disorder.     

Cognitive impairment and enduring negative symptoms: a comparative study of geriatric and nongeriatric schizophrenia patients

Chronically institutionalized geriatric (n = 174; average length of hospitalization = 35.1 years) and nongeriatric (n = 59; average length of hospitalization = 17.3 years) schizophrenia patients were classified with regard to their enduring negative symptoms (ENS) over a year. All patients completed neuropsychological tests that have been previously found to be implicated in geriatric schizophrenia: the Mini-Mental State Examination (MMSE), the Modified Boston Naming Test, Constructional Praxis, and Word List Learning and Delayed Recall. With MMSE scores used as covariates, ENS status and age group effects were examined on the cognitive measures at the second assessment. Results indicated that there was considerable specificity of cognitive impairment in the ENS syndrome even in patients with a chronic course of unremitting illness. Furthermore, when specific cognitive measures were examined and global impairment statistically controlled for, patients with ENS manifested a distinct pattern of impairment, rather than uniformly inferior performance. In particular, patients with ENS performed more poorly on tests putatively sensitive to frontal and parietal lobe functions, replicating earlier results on younger patients with a much better overall functional outcome. These data suggest that ENS defines a distinct subgroup of patients that can be identified even against the backdrop of chronic institutionalization.     

Assessment of negative and positive symptoms in schizophrenia

Reliable, convenient rating scales to assess negative and positive symptoms in schizophrenia are necessary to evaluate further the theoretical and clinical importance of this division of symptoms and signs. The authors describe the application of the Rasch model, a probabilistic, item-independent, and sample-independent test construction procedure to the development of scales for both types of symptoms. The scales for negative and positive symptoms, which are based separately on the Schedule for Affective Disorders and Schizophrenia-Current (SADS-C) and the Nurses' Observation Scale for Inpatient Evaluation (NOSIE), demonstrated excellent reliability and temporal stability (i.e., yielded a rank order of patients that remained stable over time). The pattern of interscale correlations supports the view that positive symptoms, cognitive-affective negative symptoms, and social withdrawal are independent of one another.     

Dexamethasone suppression test in positive and negative schizophrenia

Fifty-four inpatients with a DSM-III diagnosis of schizophrenia were studied. Patients were divided into positive and negative subtypes of schizophrenia according to Andreasen's criteria. Blood samples were obtained from all patients for 2 consecutive days to determine plasma cortisol concentrations before and after a single administration (1 mg, p.o.) of dexamethasone at 11 p.m. The results revealed a significant increase in plasma cortisol levels in schizophrenic patients, with 40% of the patients being nonsuppressors on the dexamethasone suppression test. A higher percentage (62.5%) of patients with the negative form of schizophrenia were nonsuppressors.     

Neuroleptic responsivity of negative and positive symptoms in schizophrenia

The authors prospectively examined the effects of double-blind, placebo-controlled neuroleptic withdrawal and administration on ratings of negative and positive symptoms in 19 young patients with chronic schizophrenia. Negative symptoms were significantly reduced by neuroleptic treatment, and negative and positive symptoms demonstrated similar patterns of reduction and exacerbation during neuroleptic treatment and withdrawal, respectively. The changes in negative and positive symptoms induced by neuroleptic treatment and withdrawal were not significantly correlated, however. The negative and positive symptom profiles of individual patients were significantly altered by neuroleptic treatment, indicating limitations to the cross-sectional classification of patients on the basis of predominance of one or the other symptom group. The authors discuss implications for the neurobiological underpinnings of negative and positive symptoms.     

Comorbid substance-use in schizophrenia: relation to positive and negative symptoms

As substance use disorders (SUD) are common in schizophrenia patients, we tested the hypothesis that comorbid patients (SUD[+]) have more positive vs. negative symptoms than non-comorbid (SUD[-]) patients. From reports identified by literature-searching we compared Positive and Negative Syndrome Scale (PANSS) ratings in schizophrenia patients with and without SUD using meta-analytic methods. Among 9 comparisons (N=725 subjects), SUD[+] patients were more often men, and abused alcohol>cannabis>cocaine. SUD[+] patients had very significantly higher PANSS-positive, and lower PANSS-negative scores. Comorbid SUD in schizophrenia patients was associated with male sex and higher PANSS positive to lower negative scores. Cause-effect relationships remain to be clarified.     

Assessment of enduring deficit and negative symptom subtypes in schizophrenia.

The clinical importance of subtypes based on enduring deficit or negative symptoms was examined in a group of schizophrenic patients who were assessed twice over a 1-year period. Subgroups of patients with high levels of enduring negative or deficit symptoms, based on the Scale for the Assessment of Negative Symptoms and the Quality of Life Scale, had a poorer prognosis and were consistently worse in social adjustment, quality of life, and thought disorder over the year than were patients with less severe negative symptoms. Subtypes based on Andreasen's negative schizophrenia classification and on enduring thought disorder were only weakly related to other symptoms and social adjustment. Social-skill deficits were weakly related to the enduring negative symptom subtype and Andreasen's negative schizophrenia. The results suggest that enduring negative and deficit symptoms may be associated with a poor outcome in schizophrenia, including more severe positive symptoms, lower levels of social adjustment, and a poorer quality of life.     

Social burden of positive and negative schizophrenia.

Sixty patients diagnosed as 'positive' or 'negative' schizophrenics were studied to evaluate social burden experienced by a key relative. The study had a prospective design and the patients were followed for a period of six months. At the time of initial assessments, in the 'positive schizophrenia' group, no significant correlation between ratings on psychopathology and social burden was observed, although at the end of the period of follow-up significant reductions in ratings on psychopathology and social burden as well as significant correlation between severity of psychopathology and burden of care were noted. In the 'negative schizophrenia' group, the severity of psychopathology and social burden were significantly correlated, but at the end of six months no significant change either in severity of psychopathology or social burden emerged.     

女性精神分裂症患者认知障碍与阴、阳性症状关系的探讨

目的 研究女性精神分裂症患者认知障碍与阴、阳性症状群的关系.方法 将新入院且未经治疗的女性精神分裂症患者按要求分为阳性症状群组(P组)和阴性症状群组(N组),并分别做韦氏记忆量表(WMS)和威斯康星卡片分类测验(WCST)检查.结果 WMS检查显示,阳性症状群组明显优于阴性症状群组,有显著性差异,健康对照组理解因子显著优于阳性症状组,但其他各因子与阳性对照组无显著性差异.WCST检查阳性症状群组Rc、Re、Rpe三因子明显优于阴性症状群组,阳性症状群组和健康对照组无显著性差异.结论 女性分裂症患者认知障碍与阴性症状群的关系明显较阳性症状群密切.     

Risperidone,negative symptoms and cognitive deficit in schizophrenia: an open study

The aim of this study was to evaluate the effects of a new antipsychotic compound on negative symptoms and cognitive deficit in schizophrenia. Psychiatric symptoms and cognition were assessed in 25 patients with schizophrenia, at baseline and after they had taken risperidone for 4 weeks. The Positive and Negative Symptoms Scale (PANSS), the Wisconsin Card Sorting Test (WCST) and two WAIS sub-tests were used to assess the patients. After the study period, both negative and positive symptoms and also measures of cognitive performance improved significantly. The WCST results correlated with negative symptom scores before and after treatment. This suggests that negative symptoms and cognitive deficit have a common underlying substrate which is the target of the risperidone treatment. Our data show that risperidone may have a substantial effect on complex cognitive functions in schizophrenia, and they suggest that certain cognitive deficits are relatively dependent on the negative symptoms of this disorder.     

以阴、阳性症状为主的精神分裂症患者威斯康星卡片分类测验的比较研究

目的探讨精神分裂症患者认知功能障碍的特点。方法对２３例以阴性症状为主的精神分裂症、３０例以阳性症状为主的精神分裂症和２８名正常人进行了威斯康星卡片分类测验（ＷＣＳＴ）。结果显示以阴性症状为主的精神分裂症患者的总测验次数、持续错误数和非持续错误数明显高于以阳性症状为主的精神分裂症患者和正常人，差异有显著性（Ｐ＜０．０５）。同时发现，ＷＣＳＴ的以上测验指标在两组患者之间差异亦有显著性（Ｐ＜０．０５）。相关分析显示，以阴性症状为主的精神分裂症患者的Ａｎｄｒｅａｓｅｎ阴性症状量表总分与简明精神病评定量表的迟滞因子分和持续错误数呈显著正相关（ｒ分别为０．４３７２和０．４５５１）。结论提示精神分裂症患者存在执行功能障碍，其中阴性症状可能与额叶功能缺陷有关。     

Cognitive and clinical predictors of success in vocational rehabilitation in schizophrenia

Cognitive impairments in schizophrenia appear to be associated with social problem solving, social and vocational functioning, and psychosocial skill acquisition. The present study examined the relationship of cognitive functioning, as well as clinical symptoms, to vocational outcomes among individuals with schizophrenia. One hundred and twelve participants with DSM-IV schizophrenia spectrum diagnoses underwent a comprehensive neuropsychiatric evaluation after enrolling in one of several employment programs. The neuropsychological evaluation examined verbal learning and memory, attention, speed of information processing, and executive functioning. Clinical symptoms were evaluated with the Positive and Negative Syndrome Scale (PANSS). Vocational outcomes were assessed 4 months after baseline assessment and included both measures of employment outcome (e.g., earnings) and of work performance as assessed by the Work Behavior Inventory (WBI). Negative symptoms, learning and memory performance, processing speed, and executive functioning were related to hours, weeks, and wages earned on the job. Stepwise multiple regression analyses found that among baseline clinical and cognitive predictors, only verbal learning and memory and cognitive disorganization symptoms were significant predictors of work behaviors 4 months later. Learning and memory were the only significant predictors of integrated employment at 4 months. These results suggest specific aspects of cognition may be modestly predictive of vocational outcomes.     

Preliminary analysis of positive and negative syndrome scale in ketamine-associated psychosis in comparison with schizophrenia

ObjectiveStudies of the effects of the N-methyl-d-aspartate (NMDA) glutamate receptor antagonist, ketamine, have suggested similarities to the symptoms of schizophrenia. Our primary goal was to evaluate the dimensions of the Positive and Negative Syndrome Scale (PANSS) in ketamine users (acute and chronic) compared to schizophrenia patients (early and chronic stages).MethodWe conducted exploratory factor analysis for the PANSS from four groups: 135 healthy subject administrated ketamine or saline, 187 inpatients of ketamine abuse; 154 inpatients of early course schizophrenia and 522 inpatients of chronic schizophrenia. Principal component factor analyses were conducted to identify the factor structure of the PANSS.ResultsFactor analysis yielded five factors for each group: positive, negative, cognitive, depressed, excitement or dissociation symptoms. The symptom dimensions in two schizophrenia groups were consistent with the established five-factor model (Wallwork et al., 2012). The factor structures across four groups were similar, with 19 of 30 symptoms loading on the same factor in at least 3 of 4 groups. The factors in the chronic ketamine group were more similar to the factors in the two schizophrenia groups rather than to the factors in the acute ketamine group. Symptom severities were significantly different across the groups (Kruskal–Wallis χ²(4) = 540.6, p < 0.0001). Symptoms in the two ketamine groups were milder than in the two schizophrenia groups (Cohen's d = 0.7).ConclusionOur results provide the evidence of similarity in symptom dimensions between ketamine psychosis and schizophrenia psychosis. The interpretations should be cautious because of potential confounding factors.     

Olfactory acuity in the positive and negative syndromes of schizophrenia

The olfactory thresholds of 46 schizophrenic subjects were measured. This group yielded 11 patients with a stringently defined positive syndrome and 12 with a negative syndrome when rated with the Positive and Negative Syndrome Scale. The negative group had a significantly (p less than 0.01) higher olfactory threshold than the positive group although neither of the groups differed significantly from a control group. Implications of this finding are discussed.     

Premorbid personality and positive and negative symptoms in schizophrenia.

The relationship between premorbid personality and schizophrenic symptoms assessed by the Scales for the Assessment of Positive and Negative Symptoms was explored in 115 DSM-III-R schizophrenics. The frequencies of normal, schizoid-schizotypal and other DSM-III-R personality disorders were 44%, 39% and 17%. Affective flattening and alogia were significantly more frequently present and severe in the schizoid-schizotypal group than in the rest of the patients. There were no differences in positive symptoms. It is suggested that, in some cases, negative symptoms are merely the persistence or exacerbation of schizoid traits present prior to the emergence of schizophrenic symptoms. These results should be cautiously interpreted because the premorbid personality was diagnosed in a retrospective way and the negative symptoms were assessed cross-sectionally.     

Differential efficacy of olanzapine for deficit and nondeficit negative symptoms in schizophrenia

OBJECTIVE: Atypical antipsychotic medications have generally been found to be more effective than conventional antipsychotics in the treatment of negative symptoms. Whether the benefits derived from the atypical agents are the result of improvements in primary versus secondary negative symptoms is unclear. The authors examined the effects of olanzapine on primary and secondary negative symptoms for patients with severe negative symptoms who did or did not have the deficit syndrome.METHOD: Thirty-nine outpatients with schizophrenia and severe negative symptoms were assessed for the presence of the deficit syndrome and entered into a 12-week, open-label study of olanzapine. Positive and negative symptoms, extrapyramidal side effects, quality of life, and level of functioning of the patients were assessed at baseline and endpoint.RESULTS: All 39 patients completed the 12-week protocol; 13 of the patients had deficit negative symptoms, and 26 had nondeficit negative symptoms. Patients who had nondeficit negative symptoms demonstrated improvements in positive and negative symptoms, level of functioning, and extrapyramidal side effects over baseline. In contrast, patients meeting criteria for the deficit syndrome improved significantly over baseline only in extrapyramidal side effects.CONCLUSIONS: The results of this study suggest that olanzapine is efficacious for secondary negative symptoms in schizophrenia but fail to support the contention that olanzapine has a direct beneficial effect on primary negative symptoms.