Deficits in sustained attention in schizophrenia but not in bipolar disorder

Schizotypy and perceptual span in a non-clinical sample: a virtual reality study

INTRODUCTION

Individuals with high schizotypy or schizophrenia exhibit difficulties in distributing their attention across space, leading to a reduction in their "perceptual span" - the extent of visual space that can be attended to at once. In this study, we aim to explore the correlation between schizotypy and perceptual span in a non-clinical sample to investigate whether perceptual span correlates with schizotypy across its range.

METHODS

Schizotypy was assessed in fifty-five participants using the Schizotypy Personality Questionnaire (SPQ; Raine, 1991). Participants were required to attend to two dynamic targets displayed in a head-mounted virtual reality display. Perceptual span was estimated as the lateral angle of separation between the two targets beyond which performance in the task dropped to threshold.

RESULTS

Participants with higher schizotypy scores performed significantly worse on the task. Of all the factors associated with schizotypy, the shared variance between Disorganisation and Cognitive/Perceptual Factors was most predictive of task performance.

CONCLUSION

The results support the hypothesis that schizotypy predicts perceptual span in non-clinical samples. Furthermore, the demonstration of a reduced perceptual span in individuals with higher trait schizotypy shows that variations in an individual's capacity to divide attention across space can be accurately captured using a virtual reality head-mounted display.

Inferior frontal gyrus seed-based resting-state functional connectivity and sustained attention across manic/hypomanic, euthymic and depressive phases of bipolar disorder

OBJECTIVE

Seed-based resting-state functional connectivity (rs-FC) of inferior frontal gyrus (IFG), as well as sustained attention cognitive deficit are consistently reported to be impaired in bipolar disorders. However, whether these deficits exist across mood states and euthymic state are lacking. We compared rs-FC of IFG and sustained attention of bipolar patients in (hypo) mania, depression and euthymia, with controls. We also explored the interrelationships between clinical, cognitive, and imaging measurements.

METHODS

Participants included 110 bipolar subjects: 46 manic/hypomanic, 35 euthymic, and 29 depressed, matched with 41 healthy controls (HCs) underwent structural magnetic resonance imaging (MRI) and resting-state functional MRI scans. Seed-based functional connectivity analyses were performed focused on bilateral IFG seeds. Clinical symptoms and sustained attention function were measured. Stepwise linear regression analysis was conducted to explore predictors of sustained attention measurements.

RESULTS

Increased rs-FC between right IFG and bilateral frontal pole/superior frontal gyrus, precuneus, and posterior cingulate gyrus, as well as decreased rs-FC between right IFG and sensorimotor areas, anterior middle cingulate gyrus were found in all three bipolar subgroups compared with HCs. Impaired sustained attention measurement was found in bipolar manic/hypomanic and depressive subgroups compared with HCs. Linear regression analyses revealed a significant impact of the manic symptoms and psychotic symptoms on the performance of sustained attention task.

CONCLUSIONS

Our results revealed that IFG seed-based resting-state functional networks involved in emotion regulation and cognitive function were trait-like deficit in bipolar patients. Higher manic levels and psychotic symptoms were predictors of a worse sustained attention performance.

Sustained and selective attention deficits as vulnerability markers to psychosis

The first descriptions of schizophrenia emphasized attention problems patients with schizophrenia have but recent results evidence that other psychotic disorders share them.

We compared the performance in sustained and selective attention between psychotic patients (P), their healthy first degree relatives (R) and healthy volunteers (C) to prove whether these alterations could be an endophenotype of vulnerability to psychosis. We also compared the performance of schizophrenic patients (SZP) and that of patients with other functional psychoses (OP) in order to prove whether these alterations are specific of any psychotic disorder.

Seventy-six P, 70 R and 39 C were included in the study. A selective attention index, comprising TMT A and B and Stroop Test, and a sustained attention index comprising the Continuous Performance Test were calculated. We conducted an univariant general linear model to compare three group performances in these indexes, with age, sex and years of education as a covariables.

We found significant differences between the indexes when we compared P, R and C. No differences in performance were found between SZP and OP. Our data showed that sustained and selective attention alterations could be a vulnerability factor to psychotic disorders in general, but they were not specific of schizophrenia.

Sustaining attention to simple visual tasks: a central deficit in schizophrenia? A systematic review

Impairments in sustained attention, that is, the ability to achieve and maintain the focus of cognitive activity on a given stimulation source or task, have been described as central to schizophrenia. Today, sustained attention deficit is still considered as a hallmark of schizophrenia. Nevertheless, current findings on this topic are not consistent. To clarify these findings, we attempt to put these results into perspective according to the type of assessment (i.e., overall and over time assessment), the participants' characteristics (i.e., clinical and demographic characteristics), and the paradigms (i.e., traditionally formatted tasks, go/no-go tasks, and the sustained attention task) and measures used. Two types of assessment lead to opposite findings; they do not evaluate sustained attention the same way. Studies using overall assessments of sustained attention ability tend to reveal a deficit, whereas studies using over time assessments do not. Therefore, further research is needed to investigate the underlying cognitive control mechanisms of changes in sustained attention in schizophrenia.

RETRACTED: The effects of perceptual load in processing emotional facial expression in psychotic disorders

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the authors and Editor-in-Chief. The Authors have recently discovered an error in the database that affects the results and, consequently, the discussion, conclusions and abstract of this article on the effects of perceptual load and task-irrelevant facial expression during a target-letter discrimination task in psychotic disorders. The error was discovered by the Authors during the analysis of new data using the same experimental task, but collected from a distinct clinical sample, and involves a systematic error in the database: pictures of one actor were coded as depicting the same valence (angry, happy, neutral) during the programming of the experimental task, regardless of the real facial expression portraited by the picture in each trial. As a result, the information provided by the ‘Emotion’ variable in the database, created by the E-Prime software for each participant during the performance of the task, was not correct. Because the Authors used the ‘Emotion’ variable to perform the statistical analysis, the results of lower accuracy for individuals diagnosed with psychotic disorders in trials where the task-irrelevant stimuli are happy facial expressions - as revealed by a significant interaction between group and facial expression (p = .016) and between group, perceptual load and facial expression (p = .027) - are not correct, thus partially affecting the discussion, conclusions and abstract of the manuscript. Besides the ‘Emotion’ variable, the raw database contains the filename of the picture presented in each trial. Therefore, the Authors were able to correct the error and to re-analyse the data, and will proceed with the submission for publication of the corrected version of the manuscript. The error had no influence on the design and procedure of the experimental task, as the order of the pictures was fully randomized per participant. The Authors apologize for the inconvenience caused by these mistakes and agree with the retraction. The Authors advise all researchers to pay special attention when scripting/coding the stimuli to be used in the experimental tasks, and to confirm all scripting/coding with independent researchers, whenever possible, to prevent mistakes (Strand, 2021). The Journal apologizes that these errors were not detected during peer review.

Not All Differences between Patients with Schizophrenia and Healthy Subjects Are Pathological: Performance on the Conners' Continuous Performance Test

OBJECTIVE

This study analyzed attentional performance in patients with schizophrenia during a continuous performance task requiring a high response rate.

METHOD

The Conners' Continuous Performance Test-II (CPT-II) was administered to 64 patients with schizophrenia and 64 healthy comparison subjects. A cross-sectional design was used in order to allow analysis of the means between patients and healthy subjects. Differences in performance were assessed for significance using ANCOVA. Percentiles were also analyzed in order to determine whether a participant showed normal or pathological performance. Pearson's correlation was used to detect possible relationships between attentional performance and psychopathology.

RESULTS

Of the 12 CPT-II measures, response style and slowing of reaction time (RT) between targets increased to similar extents between patients and healthy comparison subjects. Patients performed significantly less well than non-patient group on all other measures. Nevertheless, patient's performance on four of these measures remained within the normal range, and patient's performance on the remaining measures qualified as pathological only in the case of variability in hit RT. No significant correlations between attention performance and symptoms were found.

CONCLUSIONS

These results suggest that although patients may show lower attentional functioning than non-patients on tasks requiring a high response rate, their attentional performance remains within the normal range on most dimensions.

The role of attention processes in facial affect recognition in schizophrenia

INTRODUCTION

Studies investigating the involvement of attention processes in facial affect recognition (FAR) have been contradictory, with some suggesting a generalised cognitive deficit, whereas others a specialised deficit in affect recognition. Given the ubiquity of both attention and emotion perception deficits in schizophrenia, we examined whether specific attentional processes, in fact, mediate FAR.

METHODS

Patients with schizophrenia (n = 38) and healthy controls (n = 24) performed tests assessing FAR and attention processes, specifically, visual attention (Trail Making Test A), sustained attention/inhibition (Rapid Visual Processing subtest; Cambridge Automated Neuropsychological Test Battery), and attention to details in facial features (AFF). AFF and FAR were assessed with newly devised experimental procedures.

RESULTS

Hierarchical multiple regression analyses showed a similar pattern of association between attention processes and FAR in both participant groups with respect to all attention processes investigated, predicting FAR accuracy. Additionally, visual attention predicted accuracy in happiness, disgust and surprise, whereas AFF predicted accuracy in anger and fear. Regarding FAR processing speed, no attention process predicted participants' performance on correct responses; AFF response speed predicted participants' FAR response speed, but only on incorrect responses.

DISCUSSION

The present findings highlight the role of attentional processes in emotion recognition, as deficits in the former were predictive of impairments in the latter. Furthermore, AFF appears to be involved in the discrimination of negatively valenced facial expressions. The lack of association between attentional processes and FAR processing speed, particularly regarding correct responses, might reflect the differential pattern of activation of cortical and subcortical structures involved in these cognitive processes.

Electrical mapping in bipolar disorder patients during the oddball paradigm

Bipolar disorder (BD) is characterized by an alternated occurrence between acute mania episodes and depression or remission moments. The objective of this study is to analyze the information processing changes in BP (Bipolar Patients) (euthymia, depression and mania) during the oddball paradigm, focusing on the P300 component, an electric potential of the cerebral cortex generated in response to external sensorial stimuli, which involves more complex neurophysiological processes related to stimulus interpretation. Twenty-eight bipolar disorder patients (BP) (17 women and 11 men with average age of 32.5, SD: 9.5) and eleven healthy controls (HC) (7 women and 4 men with average age of 29.78, SD: 6.89) were enrolled in this study. The bipolar patients were divided into 3 major groups (i.e., euthymic, depressive and maniac) according to the score on the Clinical Global Impression--Bipolar Version (CGI-BP). The subjects performed the oddball paradigm simultaneously to the EEG record. EEG data were also recorded before and after the execution of the task. A one-way ANOVA was applied to compare the P300 component among the groups. After observing P300 and the subcomponents P3a and P3b, a similarity of amplitude and latency between euthymic and depressive patients was observed, as well as small amplitude in the pre-frontal cortex and reduced P3a response. This can be evidence of impaired information processing, cognitive flexibility, working memory, executive functions and ability to shift the attention and processing to the target and away from distracting stimuli in BD. Such neuropsychological impairments are related to different BD symptoms, which should be known and considered, in order to develop effective clinical treatment strategies.

Controlled shifting of attention in schizophrenia and bipolar disorder through a dichotic listening paradigm

The dichotic listening (DL) task was developed originally to examine bottom-up or "automatic" information processing. More recently, however, it has been used as a tool in the study of top-down or "controlled" information processing. This has been done by including forced-choice conditions, wherein the examinee is required to focus attention on one or the other ear. It has been widely utilized with patients with schizophrenia, who exhibit rather severe deficits in managing their attention, but not with other patient groups, such as patients with bipolar disorder. In the present study, we examined potential performance similarities in the DL listening task. In total, the sample consisted of 38 patients with schizophrenia, 20 patients with psychotic bipolar disorder and 35 healthy individuals, who performed a DL task with verbal stimuli once at the beginning of their hospitalization and again on the last day before discharge. Our findings indicated that both patient groups showed similarly diminished performance when compared to healthy participants at both times of administration. Symptom improvement between the two evaluations did not significantly influence performance in the DL task. In conclusion, impaired automated and controlled information processing appears to be a common deficit in both schizophrenia and bipolar disorder.

P300 aberration in first-episode schizophrenia patients: a meta-analysis

BACKGROUND

Decreased P300 amplitude is one of the most consistent findings in patients with schizophrenia. However, whether prolonged P300 latency occurs in patients with schizophrenia, especially first-episode schizophrenia (FES) patients, remains controversial.

METHODS

A meta-analyses of P300 aberration in FES patients and healthy control(HC) group was conducted. The meta-regression analysis was performed using a random effects model. The pooled standardized effect size (PSES) was calculated as the division of the difference between the means of the two groups by the common standard deviation.

RESULTS

A total of 569 FES patients and 747 HCs were included in this meta-analysis. P300 amplitude was significantly reduced (PSES = -0.83, 95% CI: -1.02-0.65, P = 0.00001) and P300 latency was delayed significantly in FES patients (PSES = -0.48, 95% CI: 0.14-0.81, P = 0.005). The meta-regression analysis showed that task difficulty was a source of heterogeneity.

CONCLUSIONS

The meta-analysis confirms that disrupted information processing is found in FES patients, which is manifested by smaller P300 amplitude and delayed P300 latency.

Reduced P3a amplitudes in antipsychotic naïve first-episode psychosis patients and individuals at clinical high-risk for psychosis

Event related potentials (ERP) associated with early sensory information processing have been proposed as possible vulnerability markers for psychosis. Compared to other ERPs reported in schizophrenia research, like Mismatch Negativity (MMN), little is known about P3a, an ERP related to novelty detection. The aim of this study was to analyze the MMN-P3a complex in 20 antipsychotic naïve first-episode psychosis patients (FEP), 23 antipsychotic naïve individuals at clinical high-risk for psychosis (CHR) and 24 healthy controls. The MMN-P3a amplitudes and latencies were obtained during a passive auditory mismatch frequency deviant ERP paradigm and analyzed in frontal and central scalp regions. There were no significant differences in MMN amplitude between groups. There was a significant group difference in P3a due to reduced amplitude (F[2,64] = 3.7, p = 0.03) in both CHR and FEP groups (Mean difference (MD) = 0.39, p = 0.04 and MD = 0.49, p = 0.02, respectively) compared to the control group and this effect was most prominent on the right side (Group × laterality effect: MD = 0.57, p < 0.01 and MD = 0.58, p < 0.01, respectively). No significant differences were observed for MMN or P3a latencies between groups. Although a P3a decrement in chronic schizophrenia and FEP has been previously reported, our results suggest that this novelty detection impairment is present even in pre-psychosis stages in antipsychotic naïve subjects. This study supports the evidence that P3a could represent a neurophysiological vulnerability marker for the development of psychosis.

Experiencing malevolent voices is associated with attentional dysfunction in psychotic patients

Inattention in people with schizophrenia is common. However, there has been little research on the association between inattention and auditory hallucinations. The aim of the study was to investigate how inattention is affected by beliefs about voices as benevolent and malevolent and perceived control of voices. A total of 31 patients who experienced auditory hallucinations and who met the criteria for schizophrenia or other psychosis completed the attention subscale of the Scale for the Assessment of Negative Symptoms (SANS) and the Connors’ Continuous Performance Test II (CCPT-II). The revised Beliefs About Voices Questionnaire (BAVQ-R) was used to assess malevolent and benevolent beliefs about voices, and severity of auditory hallucinations (the Psychotic Symptom Rating Scales; PSYRATS) was used to assess perceived control of voices and frequency of voices. Levels of depression (the Beck Depression Inventory; BDI), anxiety (the Beck Anxiety Inventory; BAI), severity of overall psychiatric symptoms (the Brief Psychiatric Rating Scale; BPRS), and severity of negative symptoms (SANS) were assessed to control for their potential confounding effects. The relations between the variables were explored with correlations and multiple hierarchical regression analyses. The results indicated that more malevolent, but not more benevolent, beliefs about voices predicted lower levels of attention, independently of general psychiatric symptoms and various other psychotic symptoms such as frequency of and perceived control of voices. These findings suggest an important relationship between malevolent beliefs about voices and levels of inattention. The possible impact of changing beliefs about voices to improve attentional functioning is discussed.

The visual P3a in schizophrenia and bipolar disorder: effects of target and distractor stimuli on the P300

Amplitude reduction of the P300 event-related potential has long been suggested as a marker for schizophrenia. However, recent research has shown that this reduction in the P300 amplitude is not specific to schizophrenia as it can also be observed in related illnesses such as bipolar disorder. Due to this lack of specificity the P300 elicited using traditional oddball paradigms may be a less valuable endophenotypic marker. The current study employed a cognitively demanding three-stimulus oddball paradigm to elicit the P300 to visual target and distracting stimuli. Patients with schizophrenia showed amplitude reductions of P300 components to targets, distractors and frequent stimuli. The P300 in patients with bipolar disorder was not significantly different from either group. The pattern of results may further the understanding of the nature of the impairment in schizophrenia.

Sustained attention deficits among HIV-positive individuals with comorbid bipolar disorder

Difficulties with sustained attention have been found among both persons with HIV infection (HIV+) and bipolar disorder (BD). The authors examined sustained attention among 39 HIV+ individuals with BD (HIV+/BD+) and 33 HIV-infected individuals without BD (HIV+/BD-), using the Conners' Continuous Performance Test-II (CPT-II). A Global Assessment of Functioning (GAF) score was also assigned to each participant as an overall indicator of daily functioning abilities. HIV+/BD+ participants had significantly worse performance on CPT-II omission errors, hit reaction time SE (Hit RT SE), variability of SE, and perseverations than HIV+/BD- participants. When examining CPT-II performance over the six study blocks, both HIV+/BD+ and HIV+/BD- participants evidenced worse performance on scores of commission errors and reaction times as the test progressed. The authors also examined the effect of current mood state (i.e., manic, depressive, euthymic) on CPT-II performance, but no significant differences were observed across the various mood states. HIV+/BD+ participants had significantly worse GAF scores than HIV+/BD- participants, which indicates poorer overall functioning in the dually-affected group; among HIV+/BD+ persons, significant negative correlations were found between GAF scores and CPT-II omission and commission errors, detectability, and perseverations, indicating a possible relationship between decrements in sustained attention and worse daily-functioning outcomes.

Insights into theory of mind in schizophrenia: the impact of cognitive impairment

The ability to mentalize and attribute beliefs, intentions and desires to others has been found by the vast majority of studies to be impaired in patients with schizophrenia. However, it is not yet clear if this deficit in Theory of Mind (ToM) is independent of their also well established deficits in basic cognitive functioning. In the present study, we sought to clarify the above relationship by exploring patients' ToM impairment after controlling for their putative cognitive deficits. We examined 36 patients with schizophrenia and 30 healthy matched controls on first and second order tasks of ToM and on commonly used neuropsychological tests. Patients performed poorly on ToM tasks even after controlling for their cognitive deficits, particularly on second order ToM. The present findings contribute to the understanding of the mechanism of ToM, suggesting that ToM deficits are core characteristics in schizophrenia and relatively independent of patients' cognitive impairment.

Prefrontal and paralimbic metabolic dysregulation related to sustained attention in euthymic older adults with bipolar disorder

OBJECTIVE

  Reports of sustained attention deficits in the euthymic phase of bipolar disorder have been variable, and have yet to be related to cerebral metabolism. In the present study, we evaluated relationships between cognitive performance deficits and resting cerebral metabolism in euthymic older adults with bipolar disorder.

METHODS

  Sixteen older (mean age 58.7 years) euthymic outpatients with bipolar disorder (10 type I, 6 type II; 44% female) and 11 age-matched healthy controls received resting positron emission tomography with (18) fluorodeoxyglucose and, within 10 days, the Conners' Continuous Performance Test-II, a commonly used measure of sustained attention and inhibitory control.

RESULTS

  Bipolar disorder patients had significantly more omission errors (z = 2.53, p = 0.01) and a trend toward more commission errors (z = 1.83, p < 0.07) than healthy controls. Relative to healthy controls, among bipolar disorder subjects commission errors were more strongly related to inferior frontal gyrus [Brodmann area (BA) 45/47] hypometabolism and paralimbic hypermetabolism. In bipolar disorder subjects, relative to controls, omission errors were more strongly related to dorsolateral prefrontal (BA 9/10) hypometabolism and greater paralimbic, insula, and cingulate hypermetabolism.

CONCLUSIONS

  In older adults with bipolar disorder, even during euthymia, resting-state corticolimbic dysregulation was related to sustained attention deficits and inhibitory control, which could reflect the cumulative impact of repeated affective episodes upon cerebral metabolism and neurocognitive performance. The relative contributions of aging and recurrent affective episodes to these differences in bipolar disorder patients remain to be established.

Deficits in visual sustained attention differentiate genetic liability and disease expression for schizophrenia from Bipolar Disorder

BACKGROUND

There is mounting evidence for shared genetic liability to psychoses, particularly with respect to Schizophrenia (SZ) and Bipolar Disorder (BD), which may also involve aspects of cognitive dysfunction. Impaired sustained attention is considered a cardinal feature of psychoses but its association with genetic liability and disease expression in BD remains to be clarified.

METHODS

Visual sustained attention was assessed using the Degraded Symbol Continuous Performance Test (DS-CPT) in a sample of 397 individuals consisting of 50 remitted SZ patients, 119 of their first degree relatives, 47 euthymic BD patients, 88 of their first degree relatives and 93 healthy controls. Relatives with a personal history of schizophrenia or bipolar spectrum disorders were excluded. Performance on the DS-CPT was evaluated based on the response criterion (the amount of perceptual evidence required to designate a stimulus as a target) and sensitivity (a signal-detection theory measure of signal/noise discrimination).

RESULTS

We found no effect of genetic risk or diagnosis for either disorder on response criterion. In contrast, impaired sensitivity was seen in SZ patients and to a lesser degree in their relatives but not in BD patients and their relatives. These findings were not attributable to IQ, medication, age of onset or duration of illness.

CONCLUSIONS

Our results argue for the specificity of visual sustained attention impairment in differentiating SZ from BD. They also suggest that compromised visual information processing is a significant contributor to these deficits in SZ.

Sustained attention as a potential endophenotype for bipolar disorder

OBJECTIVE

Nowadays, it is accepted that to identify the biological basis of psychiatric illnesses it would be useful to deconstruct them into the most basic manifestations, such as cognitive deficits. The aim of this study was to set attention deficit as a stable vulnerability marker of bipolar disorder.

METHOD

Sustained attention was evaluated by the Continuous Performance Test (DS-CPT) in 143 euthymic bipolar patients and 105 controls. To estimate the influence of clinical profile in attention, patients completed a semi-structured interview.

RESULTS

Bipolar patients showed a deficit in attention during euthymic periods. This disturbance correlated with years of evolution, age of onset and age of first hospitalisation; and was not influenced by other clinical data.

CONCLUSION

Sustained attention may be considered as an endophenotype of the illness.

Is semantic memory impaired in schizophrenia? A systematic review and meta-analysis of 91 studies

INTRODUCTION

Semantic memory impairments in schizophrenia have been reported across a wide range of neuropsychological tests. Set against a backdrop of fairly widespread cognitive impairments, it is difficult to know whether there is a primary, or secondary, impairment of semantic memory in schizophrenia. Also, whether there is a profile of differential impairment across the range of neuropsychological tests.

METHODS

Employing a systematic search strategy, 91 papers were identified which have assessed participants with schizophrenia on a measure of semantic memory. A series of meta-analyses were then conducted which provided combined weighted means for performance on tasks of naming, word-picture matching, verbal fluency, priming, and categorisation.

RESULTS

An uneven profile of impairment is reported with large effect sizes for tests of naming and verbal fluency, medium effect sizes for word-picture matching and association and small effect sizes for categorisation and priming tests.

CONCLUSIONS

This uneven profile supports the claim that a degradation of semantic knowledge may not be adequate in explaining the semantic memory impairment in schizophrenia. This conclusion is supported by the data which report a relationship between an executive dysfunction and poor priming and fluency performance particularly. The data support a link between Formal Thought Disorder and semantic memory impairments on tests of naming and verbal fluency but on other tests evidence is equivocal.

A meta-analytic investigation of neurocognitive deficits in bipolar illness: profile and effects of clinical state

A meta-analysis of neuropsychological studies of patients with bipolar disorder comprised of 42 studies of 1,197 patients in euthymia, 13 studies consisting of 314 patients in a manic/mixed phase of illness, and 5 studies of 96 patients in a depressed state. Cohen d values were calculated for each study as the mean difference between patient and control group score on each neuropsychological measure, expressed in pooled SD units. For euthymia, results revealed impairment across all neuropsychological domains, with d values in the moderate-to-large range (d = .5 - .8) for the vast majority of measures. There was evidence of large effect-size impairment on measures of verbal learning (d = .81), and delayed verbal and nonverbal memory (d = .80 - .92), while effect-size impairment on measures of visuospatial function was small-to-moderate (d <or= .55). Patients tested during a manic/mixed or depressed phase of illness showed exaggerated impairment on measures of verbal learning, whereas patients tested during a depressed phase showed greater decrement on measures of phonemic fluency. These results suggest that bipolar illness during euthymia is characterized by generalized moderate level of neuropsychological impairment with particular marked impairment in verbal learning and memory. These results also show that a subset of these deficits moderately worsen during acute disease states.

Course of cognitive functioning in first-episode psychosis: a comparison between schizophrenia and non schizophrenia psychosis

AIMS

To describe the course of cognitive functioning in first-episode psychosis and to determine possible differences in the degree and trajectory of cognitive deficits between schizophrenia and non-schizophrenia first-episode psychosis.

METHOD

We assessed attention, working memory, and executive functioning in 57 patients with first-episode psychosis both at baseline and at 1-year of follow-up.

RESULTS

For the overall group, significant reductions were found in the percentage of omission and commission errors for the sustained attention task (p<0.001 and p=0.001, respectively), in the total time to complete the Stroop-I task (p<0.001), in the percentage of omission errors for the working memory task (p=0.001), and in the percentage of perseverative errors for the Wisconsin card sorting test (WCST; p<0.001), as well as a significant increase in the number of categories completed in the WCST (p<0.001). The remaining cognitive variables analyzed remained stable (4 of the 10 variables tested). The pattern of change was similar for patients with schizophrenia (n=20) and non-schizophrenia (n=37) in the areas of attention and working memory. For executive functioning, the non-schizophrenia group showed a more beneficial pattern of change. No significant differences were detected in cognitive performance among subgroups at baseline or at the 1-year follow-up.

CONCLUSION

The course of cognitive deficits in first-episode psychosis showed significant improvements over the 1-year period in the areas of attention, working memory and executive functioning. Neuropsychological performance did not seem to be specific enough to distinguish between patients with schizophrenia and non-schizophrenia first-episode psychosis, at least during the first year.

Meta-analyses of cognitive functioning in euthymic bipolar patients and their first-degree relatives

BACKGROUND

Previous work suggests that impairments in executive function and verbal memory in particular may persist in euthymic bipolar patients and serve as an indicator of genetic risk (endophenotype).

METHOD

A systematic review of the literature was undertaken. Effects sizes were extracted from selected papers and pooled using meta-analytical techniques.

RESULTS

In bipolar patients, large effect sizes (d>0.8) were noted for executive functions (working memory, executive control, fluency) and verbal memory. Medium effect sizes (0.5<d<0.8) were reported for aspects of executive function (concept shifting, executive control), mental speed, visual memory, and sustained attention. Small effect sizes (d<0.5) were found for visuoperception. In first-degree relatives, effect sizes were small (d<0.5), but significantly different from healthy controls for executive function and verbal memory in particular.

CONCLUSIONS

Executive function and verbal memory are candidate bipolar endophenotypes given large deficits in these domains in bipolar patients and small, but intermediate, cognitive impairments in first-degree relatives.

Predicting quality of life impairment in chronic schizophrenia from cognitive variables

BACKGROUND

The aim of this study was to see whether and how cognition deficit predicts quality of life impairments in schizophrenia patients.

METHOD

The Computerized Cambridge Automated Neuropsychological Test Battery, the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q) and the Quality of Life Scale (QLS) were used to assess 62 patients with chronic schizophrenia. Step-wise multiple regression analysis was used in order to determine cognitive variables that would predict the scores of each Q-LES-Q and QLS domain scores.

RESULTS

Regression analysis revealed a significant association of the cognitive deficits with both general and domain-specific quality of life impairment measured with Q-LES-Q and QLS. Deficits in executive functions, visual sustained attention, memory and motor skills have been found to be valid predictors both before and after controlling for the severity of symptoms, emotional distress, side effects, age, education, and illness duration.

CONCLUSIONS

This study suggests that deficits in executive functioning, attention, memory and motor skills substantially contributes to predicting impairments across a wide range of HRQL domains, and, consequently, to quality of life appraisal in schizophrenia. Cognitive predictors cannot be attributed to illness-related and background variables. It can be concluded that, when aiming at the improvement of quality of life in schizophrenia patients, cognitive functioning should be targeted.

Alterações neuropsicológicas no transtorno bipolar

OBJETIVO: Revisão sistemática dos estudos controlados publicados nos últimos 15 anos sobre alterações neuropsicológicas no transtorno bipolar. MÉTODO: Foi realizado um levantamento bibliográfico no Medline, Lilacs, PubMed e ISI, selecionando-se o período de 1990 a 2005. Os estudos foram organizados a partir da comparação entre a amostra selecionada (bipolar versus outra patologia versus controles saudáveis). Nós só incluímos estudos controlados e com uma amostra de pacientes maior que 10, totalizando 73 artigos, do quais 53 foram selecionados para esta revisão. RESULTADOS: Pacientes com transtorno bipolar apresentam dificuldades em vários domínios cognitivos, sendo que alguns persistem mesmo após remissão dos sintomas. Os déficits encontrados se localizaram basicamente nas funções executivas. Na comparação com pacientes portadores de esquizofrenia, os bipolares apresentam perfil de alterações cognitivas mais leves, o que aponta para diferenças em termos de prognóstico da doença e para anormalidades em circuitos neuroanatômicos específicos. Houve correlação positiva entre déficits cognitivos e número de episódios ou internações. As medicações utilizadas para estabilização do humor podem ter um impacto negativo na cognição. CONCLUSÕES: Os prejuízos são sugestivos de disfunção em circuitos fronto-estriatais específicos que podem, em parte, explicar as dificuldades na adaptação psicossocial destes pacientes. Estudos futuros devem avaliar a eficácia de programas de reabilitação neuropsicológica, os quais visam, por meio de treinos cognitivos, minimizar o impacto dos déficits encontrados na vida diária dos pacientes.

Sustained attention deficits in manic and euthymic patients with bipolar disorder

Sustained attention deficits are proposed to be both state and trait indicators of bipolar disorder. The nature of these deficits and their association with medication and symptoms is not clear yet. The aim of this study was to investigate the impairments in various components of sustained attention task in euthymic and manic patients and was to investigate the relationship between the deficits in the manic state and medication effects. The performances of 37 manic patients, 34 euthymic patients with bipolar disorder and 34 control subjects on eight scores from Conners' CPT II, reflecting three different dimensions of sustained attention were compared. Similar to some recent findings, euthymic patients had decreased target sensitivity (omission errors) and response time inconsistency. The increased false responding (commission errors), perseveration and vigilance deficits were prominent in the manic patients. These state dependent impairments could not be explained by the impact of medication. In contrast, the exacerbation of seemingly trait-related impairments in the manic state can be at least partly explained by the impact of pharmacological therapy.