Racial effects on neuropsychological functioning in schizophrenia

OBJECTIVE: This study assessed the effects of race on neuropsychological functioning in patients with schizophrenia. METHOD: A total of 160 patients with schizophrenia completed an extensive neuropsychological test battery. Scores were standardized to a group of 99 psychiatrically and physically healthy subjects and categorized into seven functional domains: concentration, executive function, language, motor function, spatial memory, verbal memory, and visual processing. RESULTS: African Americans (N=25) had significantly lower mean scores on executive function, language, spatial memory, and visual processing than did Caucasians (N=135). Statistical control for patient and family education eliminated all significant effects. CONCLUSIONS: Educational differences in patients and families may account for some of the performance heterogeneity reported in patients with schizophrenia and should be routinely analyzed with other sociodemographic factors such as race and sex.     

Association of maternal genital and reproductive infections with verbal memory and motor deficits in adult schizophrenia

Maternal exposure to genital and reproductive infections has been associated with schizophrenia in previous studies. Impairments in several neuropsychological functions, including verbal memory, working memory, executive function, and fine-motor coordination occur prominently in patients with schizophrenia. The etiologies of these deficits, however, remain largely unknown. We aimed to assess whether prospectively documented maternal exposure to genital/reproductive (G/R) infections was related to these neuropsychological deficits in offspring with schizophrenia and other schizophrenia spectrum disorders. The cases were derived from a population-based birth cohort; all cohort members belonged to a prepaid health plan. Cases were assessed for verbal memory, working memory, executive function, and fine-motor coordination. Compared to unexposed cases, patients exposed to maternal genital/reproductive infection performed more poorly on verbal memory, fine-motor coordination, and working memory. Stratification by race revealed associations between maternal G/R infection and verbal memory and fine-motor coordination for case offspring of African-American mothers, but not for case offspring of White mothers. Significant infection-by-race interactions were also observed. Although independent replications are warranted, maternal G/R infections were associated with verbal memory and motor function deficits in African-American patients with schizophrenia.     

Frontal release signs among patients with schizophrenia, their first-degree biological relatives, and non-psychiatric controls

BACKGROUND: Frontal release signs (FRS) are a subset of neurological soft signs that are overrepresented among patients with schizophrenia and their unaffected relatives and may be correlated with neuropsychological functioning and chronicity of illness. This study sought to explore FRS and their associations with verbal memory and symptoms of schizophrenia in an African American sample of patients, and FRS and their associations with verbal memory and schizotypal features among first-degree relatives and non-psychiatric controls. METHOD: FRS, verbal memory, schizophrenia symptoms (in patients), and schizotypal features (in relatives and controls) were assessed in 63 patients with schizophrenia and related disorders, 33 of their unaffected first-degree relatives, and 51 controls. RESULTS: Patients and their relatives displayed greater FRS than controls. Among relatives and controls, greater FRS were related to greater self-reported disorganized and interpersonal features of schizotypal personality disorder. FRS were not associated with patients' schizophrenia symptoms in the expected direction. In the entire sample, greater FRS were associated with poorer verbal working memory. CONCLUSIONS: Because they are easy to assess, may be correlated with neuropsychological functioning, and appear to covary with level of genetic diathesis for schizophrenia, the study of FRS may shed light on the neurodevelopmental processes that underlie schizophrenia.     

Working memory deficit as a core neuropsychological dysfunction in schizophrenia

OBJECTIVE: This study tested the hypothesis that impaired working memory is a core deficit underlying multiple neuropsychological deficits in schizophrenia patients. METHOD: The subjects were 27 men with stable chronic schizophrenia treated with atypical antipsychotics and 38 normal participants. They were assessed with a battery of neuropsychological tests. Verbal working memory was measured with the WAIS digit span tests, and the Dot Test was used to test spatial working memory. RESULTS: In the patients, verbal working memory showed significant correlations with visual retention, visual orientation, simple motor function, visuomotor coordination, and executive function but not with memory for objects, memory for faces, recognition of facial emotions, or attention. Spatial working memory showed significant correlations with visual retention, visual orientation, memory for objects, memory for faces, and simple motor function but not attention, executive function, or visuomotor coordination. In the comparison group, no correlations between working memory and other neuropsychological functions were found. CONCLUSIONS: These findings support the hypothesis that working memory is a core deficit in schizophrenia. The authors postulate that the lower capacity for verbal and spatial "on-line storage" is rate limiting in the performance of other cognitive functions. Executive functions rely critically on the phonetic loop, complex visual functions such as object and face memory rely on the spatial on-line storage system (visuospatial scratch pad), while other functions such as visual orientation depend critically on both capacities.     

Relationship between psychopathology and cognitive functioning in schizophrenia

The purpose of this study was to delineate the relationship between positive, negative, cognitive, depressive, and excitement symptom dimensions of schizophrenia and cognitive functioning. Fifty-eight patients with schizophrenia (DSM-IV criteria) were assessed using the Positive and Negative Syndrome Scale (PANSS) and a battery of neuropsychological tests (executive function/abstraction, verbal and spatial working memory, verbal and nonverbal memory/learning, attention, visuospatial ability, and psychomotor speed). The cognitive symptom dimension correlated with executive functions, attention, verbal memory, and spatial ability. Severity of the negative symptom dimension was related to impairment in the structure of the semantic knowledge system, verbal memory, and auditory attention. In contrast, severity of the positive symptom dimension correlated only with impairment in the structure of the semantic knowledge system, and psychomotor speed. Finally, severity of the depressive and excitement symptom dimension was not associated with cognition. Correlations between symptom dimensions and cognitive measures were at best modest. Severity of cognitive and negative symptoms was mainly correlated with deficits on executive functions, semantic memory, and verbal memory, while positive symptoms only with semantic memory. These correlations were modest, suggesting that psychopathology and cognitive deficits in schizophrenia are caused, at least partially, by distinct pathophysiological processes.     

Neuropsychological performance in schizotypal personality disorder: importance of working memory

BACKGROUND: Cognitive deficits consistently have been reported in schizophrenia patients and in patients with schizotypal personality disorder. For this study, the authors wanted to identify which of the domains of cognitive impairment represent "core" deficits of schizophrenia, comparing subjects with schizotypal personality disorder to two comparison groups: healthy volunteers and patients with personality disorders unrelated to schizophrenia. METHOD: Three groups completed a neuropsychological battery: patients with DSM-III-R schizotypal personality disorder (N=82); patients with DSM-III-R personality disorders unrelated to schizophrenia (i.e., a personality disorder other than schizotypal, schizoid, or paranoid [N=44]); and healthy volunteers (N=63). The battery included the California Verbal Learning Test, Trailmaking Test parts A and B, the Dot test of working memory, the Stroop Color and Word Test, the Paced Auditory Serial Addition Test, the WMS visual reproduction test, and the WAIS-R vocabulary and block design. RESULTS: Normative standards for performance that controlled for age, gender, and education were created from the scores of the healthy volunteers. Overall, schizotypal personality disorder patients performed significantly worse than the healthy volunteers and those with personality disorders unrelated to schizophrenia. Specifically, patients with schizotypal personality disorder demonstrated impaired performance on the Paced Auditory Serial Addition Test, WMS visual reproduction test, Dot test, and California Verbal Learning Test. In addition, in a regression analysis, performance on the Paced Auditory Serial Addition Test demonstrated the largest effect size. Indeed, it accounted for unique variance above and beyond all other cognitive measures, since controlling for Paced Auditory Serial Addition Test performance abolished group differences across all other measures. CONCLUSIONS: Patients with schizotypal personality disorder demonstrated moderate cognitive impairment compared with healthy volunteers (significant for seven out of 11 measures). These differences reached statistical significance for tasks of working memory, episodic memory, and delayed recall. Working memory performance accounted for the group differences. This study supports the view that working memory represents a core deficit of schizophrenia spectrum disorders.     

Dynamic and Static Cognitive Deficits in Schizophrenia and Bipolar Disorder After the First Episode

Few studies have comprehensively examined the profile of cognitive functioning in first episode psychosis patients throughout the lifespan, and from first episode to chronic stage. We assessed functioning in general and specific cognitive functions, comparing both schizophrenia (N = 64) and bipolar I (N = 19) patients to controls (N = 103). Participants were from a population-based, case-control study of first episode psychosis patients, who were followed prospectively up to 10 years post first admission. A cognitive battery was administered at baseline and follow-up. By combining longitudinal and cross-sectional data, we were able to examine the cognitive profile of patients and controls throughout the entire age range of our sample (16–65). Schizophrenia patients exhibited widespread declines in IQ, executive function, visual memory, language ability, and verbal knowledge. However, the ages at which these declines occurred differed between functions. Deficits in verbal memory, working memory, processing speed, and visuospatial ability, on the other hand, were present at the first episode, and remained relatively static thereafter. Bipolar I patients also showed declines in IQ, verbal knowledge, and language ability, albeit at different ages to schizophrenia patients and only in verbal functions. Deficits on measures of verbal memory, processing speed, and executive function remained relatively static. Thus, both schizophrenia and bipolar I patients experienced cognitive decline in general and specific functions after the first episode, but the age at which these declines occurred differed between disorder and function. Cognitive remediation efforts may be most fruitful when targeting individual functions during specific time periods throughout adulthood.     

Working memory in schizophrenia: a review

INTRODUCTION: Working memory refers to a limited capacity system for temporary storage and processing of information that is known to depend on the integrity of the prefrontal cortex. It has been classically described as composed of a "central executive" that performs control, selection and planning functions, and two "slave" systems: on the one hand, the phonological loop that holds verbal, speech-based representations, and on the other hand, the visuospatial sketchpad that manipulates spatial and object visual representations. LITERATURE FINDINGS: Studies in schizophrenia have used different tasks that tap different processes within the working memory. Despite the variety of measures, there is solid neuropsychological evidence that patients with schizophrenia demonstrate deficits in all subsystems of working memory. Several studies have shown no correlations between working memory deficits and age, gender, premorbid IQ, duration of disease or positive syndrome, but a correlation has been found with a low-educational level, and negative and disorganization symptoms. Neuroimaging studies have provided evidence of an involvement of the dorsolateral-prefrontal cortex during working memory performance. Many studies have demonstrated a functional deficit in this area. However, several recent studies have reported either equal or increased activation of the dorsolateral-prefrontal cortex in schizophrenia during working memory performance. Working memory deficits are present early in the course of schizophrenia and they have been shown to be consistently associated with reduced levels of elementary social skills and learning capacity. Unaffected relatives of individuals with schizophrenia and individuals diagnosed with schizotypal personality demonstrate deficits in tasks designed to measure working memory function. Working memory dysfunctions might be suitable candidate markers for vulnerability. Certain executive sub-processes seem to be the most heritable component of the working memory. Working memory deficits in schizophrenia may benefit from specific stimulation of receptors such as the dopaminergic D1 receptor, adrenergic alpha-2A receptor or nicotinic receptors. Few studies on the effect of antipsychotic medication on working memory in schizophrenia have been carried out and their results are highly variable. Atypical antipsychotic drugs, notably risperidone, have appeared to improve performance in working memory tasks. Cognitive exercises can improve working memory with a six-month persistent effect.     

Neuropsychological function in obsessive-compulsive disorder: effects of comorbid conditions on task performance.

BACKGROUND: Neuropsychological testing reveals a pattern of impairment among patients with obsessive-compulsive disorder (OCD) which implicates the orbitofrontal region. Studies of neuropsychological function in OCD differ regarding performance deficits on classical tests of frontal executive function. In some studies, OCD patients did not demonstrate impaired performance on tests of executive function. However, other researchers have documented performance deficits among OCD patients on measures of executive function. Patients with OCD also exhibit performance deficits on tests of visual/spatial memory and verbal memory. Again, in some studies, OCD patients did not demonstrate impaired performance on tests of memory function. How can we account for the conflicting findings? One possibility is that performance deficits on tests of cognitive function are associated with comorbid conditions. In prior work, we observed that OCD patients who did poorly on executive function tasks obtained high scores on a measure of schizotypal personality. A second possibility is that executive function deficits among patients with OCD are associated with comorbid depressive symptoms. METHOD: In the present study, a comprehensive neuropsychological test battery was administered to patients with OCD and matched healthy control subjects. We also administered dimensional measures of schizotypal personality and depression to patients with OCD and controls. We conducted analyses of covariance (ANCOVA), with scores on measures of schizotypal personality and depression used as covariates. RESULTS: OCD patients demonstrated performance deficits on measures of delayed memory, response inhibition, alternation learning, and obtained significantly higher scores on measures of disinhibition, impulsivity, and temporolimbic symptoms; however, OCD patients did not exhibit impaired performance on tests of executive function and verbal fluency, and did not report a significantly greater number of dysexecutive symptoms, when coexistent depressive and schizotypal symptoms were taken into account. CONCLUSION: Findings are consistent with the contention that dysfunction of an orbitofrontal-limbic network underlies OCD.     

Neuropsychological functions in patients with bipolar I and bipolar II disorder

Objectives:  The literature reports persistent cognitive impairments in patients with bipolar disorder even after prolonged remission. However, a majority of studies have focused only on bipolar I disorder (BP-I), primarily because bipolar II disorder (BP-II) is often underdiagnosed or misdiagnosed. More attention should be paid to the differences between BP-I and BP-II, especially the aspects of neuropsychological functioning. We examined the different neuropsychological functions in BP-I and BP-II patients and compared them with those of healthy controls.
Methods:  The study included 67 patients with interepisode bipolar disorder (BP-I: n = 30; BP-II: n = 37) and 22 healthy controls compared using a battery of neuropsychological tests that assessed memory, psychomotor speed, and certain aspects of frontal executive function.
Results:  The BP-I group performed poorly on verbal memory, psychomotor speed, and executive function compared to the BP-II and control groups. Both bipolar groups performed significantly less well than the control group on measures of working memory and psychomotor speed, while the BP-II group showed an intermediate level of performance in psychomotor speed compared to the BP-I and control groups. There was no difference between the groups on visual memory.
Conclusions:  BP-I was characterized by reduced performance in verbal memory, working memory, psychomotor speed, and executive function, while BP-II patients showed a reduction only in working memory and psychomotor speed. Cognitive impairment existed in both subtypes of bipolar disorder, and was greater in BP-I patients. Rehabilitation interventions should take into account potential cognitive differences between these bipolar subtypes.     

Neuropsychological functioning in first-break, never-medicated adolescents with psychosis

The purpose of the current study was to examine neuropsychological functioning in a group of never-medicated first-break adolescents with psychosis. It is the first report of cognition in a sample of adolescents with psychosis in which all patients were drug-naive. Twenty-nine adolescent patients (mean age = 16.07; SD = 2.00; 15 male and 14 female patients) experiencing their first psychotic episode and 17 age-matched and sex-matched normal volunteers (mean age = 16.88; SD = 2.39; 9 male and 8 female subjects) were recruited and assessed with a neuropsychological battery. Measures of attention, memory, language, executive functioning, perceptual motor processing, and motor speed were obtained. Psychiatric symptomatology, estimated verbal IQ, and parental socioeconomic status were also determined. Patients with psychosis were significantly more impaired than normal volunteers; effect sizes were greatest in the areas of executive functioning, attention, and memory, and significantly smaller in areas of language, perceptual motor processing, and motor speed. The pattern was not altered when differences in verbal IQ and parental socioeconomic status were controlled. Sex and age interactions indicated that younger male patients were particularly impaired. The findings demonstrate neuropsychological deficits in adolescents with psychosis and suggest that cognitive deficits are core symptoms in psychotic disorders.     

Longitudinal study of symptoms and cognitive function in chronic schizophrenia

There is conflicting evidence of a relationship between changes in symptoms and cognitive functioning in schizophrenia. This study investigated longitudinal changes in psychopathology and cognitive functioning in chronic schizophrenia utilising three different dimensional models of symptomatology. Sixty-two patients diagnosed with DSM-IV schizophrenia or schizoaffective disorder were examined on two occasions over a period of 6 months for symptom improvement, measured by Positive and Negative Syndrome Scale (PANSS) [Kay et al., Schizophr. Bull. 13 (1987) 261]. Participants also completed a comprehensive battery of neuropsychological tasks designed to assess attention, verbal and non-verbal memory, psychomotor processing and executive/frontal functioning on both occasions. Twenty-five control subjects were assessed for comparison purposes. Severity of negative symptoms predicted poor neuropsychological performance on IQ, verbal fluency and memory measures at occasion one. However, using regression analyses, significant improvements in symptom ratings over time using two-, three- or five-dimensional models did not predict improvements in any aspect of cognitive functioning measured, except motor speed. The results do not suggest a causal relationship between the course of symptoms and neuropsychological functioning in chronic schizophrenia.     

Visual perception and working memory in schizotypal personality disorder

OBJECTIVE: Patients affected by schizophrenia show deficits in both visual perception and working memory. The authors tested early-stage vision and working memory in subjects with schizotypal personality disorder, which has been biologically associated with schizophrenia. METHOD: Eleven subjects who met DSM-III-R criteria for schizotypal personality disorder and 12 normal comparison subjects were evaluated. Performance thresholds were obtained for tests of visual discrimination and working memory. Both form and trajectory processing were evaluated for each task. RESULTS: Subjects with schizotypal personality disorder showed intact discrimination of form and trajectory but were impaired on working memory tasks. CONCLUSIONS: These data suggest that subjects with schizotypal personality disorder, unlike patients affected by schizophrenia, have relatively intact visual perception. Subjects with schizotypal personality disorder do show specific deficits on tasks of comparable difficulty when working memory demands are imposed. Schizotypal personality disorder may be associated with a more specific visual processing deficit than schizophrenia, possibly reflecting disruption of frontal lobe systems subserving visual working memory operations.     

Neuropsychological profile of patients with juvenile myoclonic epilepsy: a controlled study of 50 patients

The purpose of this study was to verify possible cognitive dysfunction in patients with juvenile myoclonic epilepsy (JME) and its relationship to factors related to epilepsy and schooling. Fifty subjects diagnosed with JME and 50 controls underwent neuropsychological assessment evaluating intellectual functions, attention, memory, executive functions, and language. The patients were further divided into two subgroups on the basis of educational level: < or = 11 and >11 years of formal education. Participants diagnosed with JME scored significantly below age-, education-, and gender-matched controls on neuropsychological measures of attention, immediate verbal memory, mental flexibility, control of inhibition, working memory, processing speed, verbal delayed memory, visual delayed memory, naming, and verbal fluency. A positive correlation was observed between duration of epilepsy and cognitive decline. However, in the group of patients with >11 years of education, this correlation was not significant. In this series of patients with JME, neuropsychological evaluation suggests widespread cognitive dysfunction outside the limits of the frontal lobes. The duration of epilepsy correlated with cognitive decline, and patients with higher education manifested less progression of deficits.     

精神分裂症首次发病患者及其健康同胞认知功能的比较研究

目的 比较精神分裂症首次发病患者与健康同胞及正常对照认知功能的差异,探讨精神分裂症在认知功能领域的内表型.方法 采用目前常用的范畴流畅测验(CFT)、数字符号编码测验(DSCT)、连线测验(TMT)、韦克斯勒记忆量表第3版(WMS-Ⅲ)空间广度测验(WMS-ⅢSST)、霍普金斯词汇学习测验-修订版(HVLT-R)、简易视觉空间记忆测验-修订版(BVMT-R)、定步调听觉连续加法测验(PASAT)和威斯康星卡片分类测验-64(WCST-64)对92例精神分裂症首次发病患者(患者组)、56例健康同胞(同胞组)和62名健康对照者(对照组)的认知功能进行检测.结果 (1)患者组所有神经心理测验成绩均差于对照组,差异有统计学意义(P＜0.01).(2)同胞组的CFT、DSCT、TMT、HVLT-R即刻记忆和延迟记忆、BVMT-R即刻记忆、PASAT、WCST-64持续错误数、持续反应数和完成分类数的测验成绩差于对照组,差异有统计学意义(P＜0.05).(3)患者组与同胞组的CFT、WCST-64中的持续错误数、持续反应数和完成分类数测验成绩分别为(18.40±12.12)分比( 18.86±5.19)分、(16.48±8.19)分比(14.80±5.86)分、(18.76±10.91)分比(16.86 ±7.73)分、(1.33±2.81)分比(1.63±1.36)分,2组比较差异无统计学意义(P＞0.05),其他神经心理测验成绩比较,患者组差于同胞组,差异有统计学意义(P＜0.05).结论 精神分裂症首次发病患者存在处理速度、工作记忆、言语记忆、空间记忆、注意警觉和执行功能广泛性的认知功能损害,精神分裂症健康同胞存在处理速度、言语记忆、视觉记忆、注意警觉、执行功能的认知缺陷;语义流畅性功能和执行功能可能是精神分裂症的潜在内表型.     

Neuropsychological profile of cognitively impaired patients with schizophrenia

OBJECTIVE: Our purpose in undertaking the present study was to explore the existence of specific areas of cognitive deficits within the context of generalized poor performance in a group of Greek patients with schizophrenia. We also sought to identify any patients who might be cognitively normal. METHOD: Participants were 70 patients with schizophrenia and 42 healthy control subjects. The 2 groups were matched on age and male-female ratio but differed in their level of education. A battery of neuropsychological tests was selected to assess executive functions/abstraction, fluency, verbal and spatial working memory, verbal and nonverbal memory, attention, visuospatial ability, and psychomotor speed. RESULTS: Patients with schizophrenia performed more poorly than healthy control subjects, when we controlled for differences in level of education, on executive functions, working memory, verbal memory, nonverbal memory, fluency, visuospatial ability, and attention. In contrast, no significant differences were found between the 2 groups on psychomotor speed. Patients showed a more pronounced deficit on executive functions, verbal and visual memory, and visuospatial ability. Overall, 13% to 62% of the patients with schizophrenia scored within 1 SD of the mean z scores of healthy control group depending on the cognitive domains examined. In the entire sample of patients with schizophrenia, however, no individual scored within 1 SD of the mean z scores of the control group in all cognitive domains. CONCLUSIONS: We found a generalized deficit in cognitive functioning in a group of patients with schizophrenia. We failed to find any individual patients who were healthy across all cognitive areas. The current neuropsychological profile, indicating widespread impairment, is comparable to that reported in the international literature and thus appears to be characteristic of schizophrenia. Our findings of increased difficulties with executive functions, verbal and visual memory, and visuospatial ability support previous suggestions of generalized brain dysfunction in the pathophysiology of schizophrenia.     

Auditory verbal hallucinations and cognitive functioning in healthy individuals

Auditory verbal hallucinations (AVH) are a characteristic symptom in schizophrenia, and also occur in the general, non-clinical population. In schizophrenia patients, several specific cognitive deficits, such as in speech processing, working memory, source memory, attention, inhibition, episodic memory and self-monitoring have been associated with auditory verbal hallucinations. Such associations are interesting, as they may identify specific cognitive traits that constitute a predisposition for AVH. However, it is difficult to disentangle a specific relation with AVH in patients with schizophrenia, as so many other factors can affect the performance on cognitive tests. Examining the cognitive profile of healthy individuals experiencing AVH may reveal a more direct association between AVH and aberrant cognitive functioning in a specific domain. For the current study, performance in executive functioning, memory (both short- and long-term), processing speed, spatial ability, lexical access, abstract reasoning, language and intelligence performance was compared between 101 healthy individuals with AVH and 101 healthy controls, matched for gender, age, handedness and education. Although performance of both groups was within the normal range, not clinically impaired, significant differences between the groups were found in the verbal domain as well as in executive functioning. Performance on all other cognitive domains was similar in both groups. The predisposition to experience AVH is associated with lower performance in executive functioning and aberrant language performance. This association might be related to difficulties in the inhibition of irrelevant verbal information.     

Cognitive features in euthymic bipolar patients in old age

Objectives:  Studies of cognition in bipolar disorder (BD) have reported impairments in processing speed, working memory, episodic memory, and executive function, but they have primarily focused on young and middle-aged adults. In such studies, the severity of cognitive deficits increases with the duration of illness. Therefore, one would expect more pronounced deficits in patients with longstanding BD. The first aim of the present study was to determine the pattern and the magnitude of cognitive impairment in older euthymic BD patients. The second aim was to explore the interrelationship between these cognitive deficits and determine whether they reflect a single core impairment or the co-occurrence of independent cognitive deficits.
Methods:  Twenty-two euthymic elderly BD patients and 22 controls, matched for gender, age, and education, underwent a comprehensive neuropsychological assessment.
Results:  Compared to controls, BD patients had significantly reduced performance in processing speed, working memory, verbal fluency, and episodic memory, but not in executive function. Hierarchical regression analyses showed that verbal fluency and working memory impairments were fully mediated by changes in processing speed. This was not the case for the episodic memory dysfunction.
Conclusion:  The cognitive profile in older euthymic BD cases is similar to the one described in younger BD cohorts. Our results further suggest that impaired processing speed plays a major role in the cognitive changes observed in BD patients except for deficits in episodic memory, thus providing strong evidence that processing speed and episodic memory are two core deficits in elderly BD patients.     

Cognitive and prepulse inhibition deficits in psychometrically high schizotypal subjects in the general population: relevance to schizophrenia research

Schizophrenia and schizotypal personality disorder share common clinical profiles, neurobiological and genetic substrates along with Prepulse Inhibition and cognitive deficits; among those, executive, attention, and memory dysfunctions are more consistent. Schizotypy is considered to be a non-specific "psychosis-proneness," and understanding the relationship between schizotypal traits and cognitive function in the general population is a promising approach for endophenotypic research in schizophrenia spectrum disorders. In this review, findings for executive function, attention, memory, and Prepulse Inhibition impairments in psychometrically defined schizotypal subjects have been summarized and compared to schizophrenia patients and their unaffected first-degree relatives. Cognitive flexibility, sustained attention, working memory, and Prepulse Inhibition impairments were consistently reported in high schizotypal subjects in accordance to schizophrenia patients. Genetic studies assessing the effects of various candidate gene polymorphisms in schizotypal traits and cognitive function are promising, further supporting a polygenic mode of inheritance. The implications of the findings, methodological issues, and suggestions for future research are discussed. (JINS, 2012, 18, 1-14).     

Cognitive functioning in the early course of first-episode schizophrenia spectrum disorders

OBJECTIVE: The aim of this study was to examine possible cognitive changes throughout the early course of schizophrenia spectrum disorders. METHOD: Forty-two patients, aged 15-50 years, admitted to a first episode psychosis program (PAFIP) serving to the community of Cantabria (Spain) and 43 healthy volunteers completed a brief battery of five neurocognitive tests at four time-points over 3 months. The cognitive testing comprise five domains: attention, visuomotor speed, declarative memory, working memory and executive function. Baseline assessment occurred within 72 hour after the initiation of standard pharmacological treatment, and after then parallel forms of the tests were applied at week-2, week-6, and month-3. RESULTS: Patient scores showed a significant impairment compared to healthy volunteers in the five cognitive domains at baseline and week-2 assessments. After the first 3 months of antipsychotic treatment, the patient group performance reached healthy volunteers level on executive function (Stroop interference) and immediate verbal memory tests. In contrast, performance on working memory, sustained attention, visuomotor speed, and verbal memory delayed recall domains still remained below healthy volunteers, although visuomotor processing speed showed a significant improvement. CONCLUSION: Schizophrenia spectrum patients show heterogeneous patterns and degrees of cognitive changes that contribute to stress the importance of when, what, and how neurocognitive functioning in the early phases of the illness is evaluated.