Neuropsychological differences between first-admission schizophrenia and psychotic affective disorders

Clinical neuropsychological characteristics of bipolar disorder, with a focus on cognitive and linguistic pattern: a conceptual analysis

Neuropsychology is an academic discipline that investigates the intricate interplay between the brain, mind, and behavior. It accomplishes this by examining the underlying structure and activities of the brain, with a particular focus on psychological phenomena such as language, motivation, memory, attention, thinking, consciousness, learning, and efficacy. The assessment of neuropsychological changes in individuals diagnosed with bipolar disorder has received limited attention in comparison to other psychiatric conditions, such as schizophrenia, for instance. Nevertheless, there has been a growing interest in the etiological implications, therapies, preventions, and prognostic factors related to social competence and the quality of life of patients. The objective of this review is to compile and analyze the existing research conducted thus far on the association between cognitive abnormalities and bipolar disorder. This study has examined research conducted across many stages of the condition, including depression and mania. Additionally, it has explored comparative studies involving people with schizophrenia, as well as the potential impact of psychopharmaceutical interventions.

Metabolic risk factors of cognitive impairment in young women with major psychiatric disorder

BACKGROUND

Cognitive performance improves clinical outcomes of patients with major psychiatric disorder (MPD), but is impaired by hyperglycemia. Psychotropic agents often induce metabolism syndrome (MetS). The identification of modifiable metabolic risk factors of cognitive impairment may enable targeted improvements of patient care.

OBJECTIVE

To investigate the relationship between MetS and cognitive impairment in young women with MPD, and to explore risk factors.

METHODS

We retrospectively studied women of 18-34 years of age receiving psychotropic medications for first-onset schizophrenia (SCH), bipolar disorder (BP), or major depressive disorder (MDD). Data were obtained at four time points: presentation but before psychotropic medication; 4-8 and 8-12 weeks of psychotropic therapy; and enrollment. MATRICS Consensus Cognitive Battery, (MCCB)-based Global Deficit Scores were used to assess cognitive impairment. Multiple logistic analysis was used to calculate risk factors. Multivariate models were used to investigate factors associated with cognitive impairment.

RESULTS

We evaluated 2,864 participants. Cognitive impairment was observed in 61.94% of study participants, and was most prevalent among patients with BP (69.38%). HbA1c within the 8-12 week-treatment interval was the most significant risk factor and highest in BP. Factors in SCH included pre-treatment waist circumference and elevated triglycerides during the 8-12 weeks treatment interval. Cumulative dosages of antipsychotics, antidepressants, and valproate were associated with cognitive impairment in all MPD subgroups, although lithium demonstrated a protect effect (all P < 0.001).

CONCLUSIONS

Cognitive impairment was associated with elevated HbA1c and cumulative medication dosages. Pre-treatment waist circumference and triglyceride level at 8-12 weeks were risk factors in SCH. Monitoring these indices may inform treatment revisions to improve clinical outcomes.

Stability of schizophrenia diagnosis in a 10-year longitudinal study on first episode of non-affective psychosis: Conclusions from the PAFIP cohort

OBJECTIVE

To evaluate the 10-year stability of schizophrenia diagnosis in a cohort of first-episode psychosis (FEP) patients and the factors associated with it.

METHODS

Changes in diagnosis of 209 FEP patients were described during 10 years of follow-up. Related factors with maintenance or change of schizophrenia diagnosis were evaluated in prospective and retrospective approaches through binary logistic regressions, ROC and survival curves.

RESULTS

Out of the 209 patients, 126 were diagnosed of schizophrenia 6 months after their inclusion in the clinical program. Prospective analyses showed that eight of those 126 schizophrenia patients had changed to a different diagnosis after 10 years, and predictors of change were better childhood premorbid adjustment, less severity of clinical global impression at baseline, and diagnosis of comorbid personality disorder during follow-up. Retrospectively, out of the 154 patients with schizophrenia in the 10-year assessment, 36 had a different diagnosis at baseline, and those factors related to a different prior diagnosis than schizophrenia were better socioeconomic status and shorter duration of untreated psychosis (DUP). A survival analysis on the timing of schizophrenia diagnosis showed that male gender and longer DUP were predictors of earlier definite diagnosis.

CONCLUSIONS

Diagnostic stability of schizophrenia in our FEP sample is high, especially prospective stability, and the group of patients with diagnostic change corresponded to a milder psychopathological profile before and at the onset of disease. Moreover, we observed a cautious attitude in the diagnosis of schizophrenia in patients with shorter DUP who had schizophrenia diagnosis after 10 years.

A comparison of cognitive performance in the Suffolk County cohort and their unaffected siblings

People diagnosed with schizophrenia and other psychoses demonstrate impaired neuropsychological performance. Their unaffected siblings exhibit mild impairments relative to unrelated controls, suggesting genetic and shared environmental risk for psychosis account for some portion of cognitive impairments observed in cases. However, most sibling studies were conducted early in illness course. Studying cases and unaffected siblings later in life is valuable because diagnostic misclassification is common early in illness, possibly leading to spurious conclusions. This study compared neuropsychological performance of individuals with psychotic disorders (schizophrenia and other psychoses), their unaffected siblings, and controls. Assessments were conducted 20 years after case enrollment in the Suffolk County Mental Health Project, when siblings and controls were added to the protocol. Results showed individuals with schizophrenia and other psychoses performed worse than their matched siblings across domains. Relative to controls, siblings of participants with schizophrenia showed mild deficits in executive function and processing speed, while no significant differences were observed between siblings of those with other psychoses and controls. These findings suggest pre- and post-onset factors impact cognitive deficits in psychosis, but pre-onset factors are more salient in schizophrenia. Additionally, schizophrenia and other psychoses exist on a neurodevelopmental continuum, with schizophrenia being a more severe manifestation.

Long-term Changes in Cognitive Functioning in Individuals With Psychotic Disorders: Findings From the Suffolk County Mental Health Project

IMPORTANCE

It remains uncertain whether people with psychotic disorders experience progressive cognitive decline or normal cognitive aging after first hospitalization. This information is essential for prognostication in clinical settings, deployment of cognitive remediation, and public health policy.

OBJECTIVE

To examine long-term cognitive changes in individuals with psychotic disorders and to compare age-related differences in cognitive performance between people with psychotic disorders and matched control individuals (ie, individuals who had never had psychotic disorders).

DESIGN, SETTING, AND PARTICIPANTS

The Suffolk County Mental Health Project is an inception cohort study of first-admission patients with psychosis. Cognitive functioning was assessed 2 and 20 years later. Patients were recruited from the 12 inpatient facilities of Suffolk County, New York. At year 20, the control group was recruited by random digit dialing and matched to the clinical cohort on zip code and demographics. Data were collected between September 1991 and July 2015. Analysis began January 2016.

MAIN OUTCOMES AND MEASURES

Change in cognitive functioning in 6 domains: verbal knowledge (Wechsler Adult Intelligence Scale-Revised vocabulary test), verbal declarative memory (Verbal Paired Associates test I and II), visual declarative memory (Visual Reproduction test I and II), attention and processing speed (Symbol Digit Modalities Test-written and oral; Trail Making Test [TMT]-A), abstraction-executive function (Trenerry Stroop Color Word Test; TMT-B), and verbal fluency (Controlled Oral Word Association Test).

RESULTS

A total of 705 participants were included in the analyses (mean [SD] age at year 20, 49.4 [10.1] years): 445 individuals (63.1%) had psychotic disorders (211 with schizophrenia spectrum [138 (65%) male]; 164 with affective psychoses [76 (46%) male]; 70 with other psychoses [43 (61%) male]); and 260 individuals (36.9%) in the control group (50.5 [9.0] years; 134 [51.5%] male). Cognition in individuals with a psychotic disorder declined on all but 2 tests (average decline: d = 0.31; range, 0.17-0.54; all P < .001). Cognitive declines were associated with worsening vocational functioning (Visual Reproduction test II: r = 0.20; Symbol Digit Modalities Test-written: r = 0.25; Stroop: r = 0.24; P < .009) and worsening negative symptoms (avolition: Symbol Digit Modalities Test-written: r = -0.24; TMT-A: r = -0.21; Stroop: r = -0.21; all P < .009; inexpressivity: Stroop: r = -0.22; P < .009). Compared with control individuals, people with psychotic disrders showed age-dependent deficits in verbal knowledge, fluency, and abstraction-executive function (vocabulary: β = -0.32; Controlled Oral Word Association Test: β = -0.32; TMT-B: β = 0.23; all P < .05), with the largest gap among participants 50 years or older.

CONCLUSIONS AND RELEVANCE

In individuals with psychotic disorders, most cognitive functions declined over 2 decades after first hospitalization. Observed declines were clinically significant. Some declines were larger than expected due to normal aging, suggesting that cognitive aging in some domains may be accelerated in this population. If confirmed, these findings would highlight cognition as an important target for research and treatment during later phases of psychotic illness.

Cognitive impairment from early to middle adulthood in patients with affective and nonaffective psychotic disorders

BACKGROUND

Cognitive impairment is a core feature of psychotic disorders, but the profile of impairment across adulthood, particularly in African-American populations, remains unclear.

METHODS

Using cross-sectional data from a case-control study of African-American adults with affective (n = 59) and nonaffective (n = 68) psychotic disorders, we examined cognitive functioning between early and middle adulthood (ages 20-60) on measures of general cognitive ability, language, abstract reasoning, processing speed, executive function, verbal memory, and working memory.

RESULTS

Both affective and nonaffective psychosis patients showed substantial and widespread cognitive impairments. However, comparison of cognitive functioning between controls and psychosis groups throughout early (ages 20-40) and middle (ages 40-60) adulthood also revealed age-associated group differences. During early adulthood, the nonaffective psychosis group showed increasing impairments with age on measures of general cognitive ability and executive function, while the affective psychosis group showed increasing impairment on a measure of language ability. Impairments on other cognitive measures remained mostly stable, although decreasing impairments on measures of processing speed, memory and working memory were also observed.

CONCLUSIONS

These findings suggest similarities, but also differences in the profile of cognitive dysfunction in adults with affective and nonaffective psychotic disorders. Both affective and nonaffective patients showed substantial and relatively stable impairments across adulthood. The nonaffective group also showed increasing impairments with age in general and executive functions, and the affective group showed an increasing impairment in verbal functions, possibly suggesting different underlying etiopathogenic mechanisms.

HPA axis in psychotic major depression and schizophrenia spectrum disorders: Cortisol, clinical symptomatology, and cognition

The Hypothalamic Pituitary Adrenal (HPA) axis has been implicated in the pathophysiology of a variety of mood and cognitive disorders. Neuroendocrine studies have demonstrated HPA axis overactivity in major depression, a relationship of HPA axis activity to cognitive performance, and a potential role of HPA axis genetic variation in cognition. In schizophrenia differential HPA activity has been found, including higher rates of non-suppression to dexamethasone challenge and higher salivary cortisol levels, which have been a premonitory risk factor for conversion to psychosis in adolescents at risk for developing schizophrenia. The present study investigated the simultaneous roles HPA axis activity and clinical symptomatology play in poor cognitive performance. Patients with major depression with psychosis (PMD) or schizophrenia spectrum disorder (SCZ) and healthy controls (HC) were studied. All participants underwent a diagnostic interview and psychiatric ratings, a comprehensive neuropsychological battery, and overnight hourly blood sampling for cortisol. Cognitive performance did not differ between the clinical groups, though they both performed more poorly than the HC's across a variety of cognitive domains. Across all subjects, cognitive performance was negatively correlated with higher cortisol, and PMD patients had higher evening cortisol levels than did SCZ and HCs. Cortisol and clinical symptoms, as well as age, sex, and antipsychotic use predicted cognitive performance. Diathesis stress models and their links to symptomatology, cognition, and HPA function are discussed.

Clinical and demographic differences between patients with manic, depressive and schizophrenia-spectrum psychoses presenting to Early Intervention Services in London

AIM

To investigate the relationship between the presenting clinical and demographic characteristics in first-episode psychosis (FEP) patients with their clinical diagnostic grouping 1 year later.

METHODS

Data from 1014 first-presentation psychosis patients from seven London-based Early Intervention Services were extracted from the MiData audit database. Associations between clinical and demographic measures at presentation and clinical diagnosis made at 1 year were assessed with analysis of variance (ANOVA) and Chi-square tests.

RESULTS

The sample comprised 76% of patients with schizophrenia-spectrum diagnoses, 9% with manic psychoses (MP) and 6% with depressive psychoses. Compared to the other 2 groups, patients who were diagnosed as having MP were younger, with higher education and shorter duration of untreated psychosis, and had higher Young Mania Rating Scale scores at presentation and lower Positive and Negative Syndrome Scale (PANSS) negative scores. Patients diagnosed at 1 year as having depressive psychosis were older and more likely to be white, with the lowest PANSS positive scores at baseline. Patients diagnosed at 1 year as having schizophrenia spectrum diagnoses were more likely to be males. Patients in the 3 diagnostic subgroups of psychosis differed on both clinical and demographic characteristics at presentation.

CONCLUSIONS

There were significant clinical and demographic differences at presentation between FEP patients who received different clinical diagnoses at 1 year. Future work should determine the extent to which these differences can be used to guide clinical care.

Neuropsychological functioning in early and chronic stages of schizophrenia and psychotic bipolar disorder

BACKGROUND

Neuropsychological impairment is common in schizophrenia and psychotic bipolar disorder. It has been hypothesized that the pathways leading to impairment differ between disorders. Cognitive impairment in schizophrenia is believed to result largely from atypical neurodevelopment, whereas bipolar disorder is increasingly conceptualized as a neuroprogressive disorder. The current investigation tested several key predictions of this hypothesis.

METHODS

Current neuropsychological functioning and estimated premorbid intellectual ability were assessed in healthy individuals (n = 260) and a large, cross-sectional sample of individuals in the early and chronic stages of psychosis (n = 410). We tested the following hypotheses: 1) cognitive impairment is more severe in schizophrenia in the early stage of psychosis; and 2) cognitive decline between early and chronic stages is relatively greater in psychotic bipolar disorder. Additionally, individuals with psychosis were classified as neuropsychologically normal, deteriorated, and compromised (i.e. below average intellectual functioning) to determine if the frequencies of neuropsychologically compromised and deteriorated patients were higher in schizophrenia and psychotic bipolar disorder, respectively.

RESULTS

Neuropsychological impairment in the early stage of psychosis was more severe in schizophrenia. Psychotic bipolar disorder was not associated with relatively greater cognitive decline between illness stages. The frequency of neuropsychologically compromised patients was higher in schizophrenia; however, substantial portions of both schizophrenia and psychotic bipolar disorder patients were classified as neuropsychologically compromised and deteriorated.

CONCLUSIONS

While schizophrenia is associated with relatively greater neurodevelopmental involvement, psychotic bipolar disorder and schizophrenia cannot be strictly dichotomized into purely neuroprogressive and neurodevelopmental illness trajectories; there is evidence of both processes in each disorder.

Medication adherence in first-episode psychosis and its association with psychopathology

BACKGROUND

The purpose of the study was to follow-up the individuals with first-episode psychosis (FEP) for a period of 1 year to assess their medication adherence rates and to identify the association between medication adherence and psychopathology.

MATERIALS AND METHODS

In a 1 year longitudinal study, 59 individuals with FEP were assessed for their sociodemographic profile and medication adherence at 1 month and 12-month follow-up period using a semi-structured per forma. Positive and negative symptoms were assessed by positive and negative syndrome scale (PANSS) while the functioning by global assessment of functioning (GAF) scale.

RESULTS

Nearly 85% of the individuals were adherent with medications during the 1-month follow-up period, 32.2% were poorly adherent at the end of 12 months. Among various factors examined for association with medication adherence, positive and negative symptoms, and global functioning of the individuals at the end of 12 months were found to significant associated with poor medication adherence.

CONCLUSION

There is a high rate of medication nonadherence in individuals with FEP at 12-month follow-up, and factors affecting nonadherence should be addressed specifically to improve medication adherence in these individuals.

Cognitive Deficits in Psychotic Disorders: A Lifespan Perspective

Individuals with disorders that include psychotic symptoms (i.e. psychotic disorders) experience broad cognitive impairments in the chronic state, indicating a dimension of abnormality associated with the experience of psychosis. These impairments negatively impact functional outcome, contributing to the disabling nature of schizophrenia, bipolar disorder, and psychotic depression. The robust and reliable nature of cognitive deficits has led researchers to explore the timing and profile of impairments, as this may elucidate different neurodevelopmental patterns in individuals who experience psychosis. Here, we review the literature on cognitive deficits across the life span of individuals with psychotic disorder and psychotic-like experiences, highlighting the dimensional nature of both psychosis and cognitive ability. We identify premorbid generalized cognitive impairment in schizophrenia that worsens throughout development, and stabilizes by the first-episode of psychosis, suggesting a neurodevelopmental course. Research in affective psychosis is less clear, with mixed evidence regarding premorbid deficits, but a fairly reliable generalized deficit at first-episode, which appears to worsen into the chronic state. In general, cognitive impairments are most severe in schizophrenia, intermediate in bipolar disorder, and the least severe in psychotic depression. In all groups, cognitive deficits are associated with poorer functional outcome. Finally, while the generalized deficit is the clearest and most reliable signal, data suggests specific deficits in verbal memory across all groups, specific processing speed impairments in schizophrenia and executive functioning impairments in bipolar disorder. Cognitive deficits are a core feature of psychotic disorders that provide a window into understanding developmental course and risk for psychosis.

Integrating non-drug treatments in early schizophrenia

There is a range of psychological interventions for established schizophrenia. These include family interventions, motivational interventions for substance misuse and for non-adherence to medication, cognitive remediation for neurocognitive deficits and cognitive–behavioural therapy for symptoms. Psychological interventions may explicitly target risk factors for poor outcome, such as substance use, or protective factors, such as adherence to medication, or be directed at specific symptoms or deficits. There is emerging evidence for efficacy of psychological treatments during, following and even prior to the first episode. Important areas for further study are how different treatment modalities can interact productively and patient and carer preferences for treatment. Many trials of psychological treatments have design flaws and this tends to overestimate the treatment effect.

Cognitive impairment in schizophrenia and depression: A comparison of stability and course

Cognitive deficits are clinically relevant features in schizophrenia and depression, yet little comparative data on changes in both disorders is available. This study compares cognitive performance of inpatients with schizophrenia (N = 52) and unipolar major depression (N = 67) during psychiatric treatment, assessing performance twice: after admission to hospital (acute) and prior to discharge (postacute) on average seven weeks later. A group of healthy controls was tested at comparable intervals. Data was analyzed using a multivariate linear model. Patients with schizophrenia and depression showed significantly impaired performance compared to healthy controls. On follow-up both patient groups showed improved performance. Contrary to expectation, patients with schizophrenia showed greater improvement in verbal memory, visual memory, and psychomotor speed than depressive patients. Verbal fluency presented as a possible candidate to differentiate between both disorders. Similar profiles of generalized cognitive deficits were observed in both patient-groups on acute and postacute assessment, which might indicate trait-like deficits with persistent functional implications in both disorders. Findings do not support assumptions of greater cognitive impairment in schizophrenia compared to depression. A distinction of the disorders on the grounds of cognitive functioning seems to be less specific than presumed.

Health status and mobility limitations are associated with residential and employment status in schizophrenia and bipolar disorder

INTRODUCTION

Schizophrenia (SCZ) and bipolar disorder (BP) are linked to multiple impairments in everyday functioning which share cognitive and symptom risk factors. Other risk factors for critical aspects of every day functioning (e.g., gainful employment; residential independence) such as physical health have not been evaluated, despite poor health in SCZ and BP.

METHODS

We analyzed 20-year follow-up data from the Suffolk County Mental Health Project cohort of consecutive first admissions with a psychotic disorder to 12 psychiatric facilities in Suffolk County, NY, between September 1989 and December 1995. Both 20-year symptom, health, and cognition data, and the 20-year course of weight gain were included as predictors of employment and residence status.

RESULTS

The analysis sample consisted of 122 participants with SCZ ad BP, with SCZ participants less likely to work or live independently. Correlational analyses showed symptoms and cognition predicted vocational outcomes in both samples. The effect of diagnosis was significant for both gainful employment and independence in residence. After consideration of diagnosis, mobility and negative symptoms predicted gainful employment in both samples, but there were no additional predictors of residential independence. Prospective analysis of BMI found that baseline BMI, but not changes during the 20-year follow up, predicted labor force participation.

DISCUSSION

Health status limitations were associated with residential and, particularly, employment status independent from other, previously established predictors of everyday outcomes, including cognition and symptoms. The importance of health status limitations for predicting outcome was confirmed in both SCZ and BP, with schizophrenia representing the more impaired group.

Working memory predicts presence of auditory verbal hallucinations in schizophrenia and bipolar disorder with psychosis

OBJECTIVE

The recent dramatic increase in research investigating auditory verbal hallucinations (AVHs) has broadened the former narrow focus on schizophrenia to incorporate additional populations that experience these symptoms. However, an understanding of potential shared mechanisms remains elusive. Based on theories suggesting a failure of top-down cognitive control, we aimed to compare the relationship between AVHs and cognition in two categorical diagnoses of psychosis, schizophrenia and psychotic bipolar disorder.

METHOD

A total of 124 adults aged 21-60 participated, of whom 76 had present-state psychosis (schizophrenia, n = 53; bipolar disorder with psychosis, n = 23), and 48 were non-clinical controls. Diagnosis and hallucination presence was determined using the Structured Clinical Diagnostic Interview for DSM-IV TR. AVHs severity was assessed using the Positive and Negative Syndrome Scale. Participants also completed the MATRICS cognitive battery.

RESULTS

The bipolar disorder with psychosis group performed better than the schizophrenia group for cognitive domains of Processing speed, Attention, Working memory (WM), and Visual memory. Hierarchical binary logistic regression found that WM significantly predicted presence of AVHs in both psychotic groups, but diagnosis did not significantly increase the predictive value of the model. A hierarchical multiple linear regression found that schizophrenia diagnosis was the only significant predictor of hallucination severity.

CONCLUSIONS

The findings of this study-the first, to our knowledge, to compare the relationship between AVHs and MATRICS domains across schizophrenia and bipolar disorder with psychosis-support theories that deficits in WM underly the genesis of AVHs. WM potentially represents a shared mechanism of AVHs across diagnoses, supporting dimensional classifications of these psychotic disorders. However, non-cognitive factors predictive of hallucination severity may be specific to schizophrenia.

Sustained Attention and Visual Processing Speed in Children and Adolescents with Bipolar Disorder and other Psychiatric Disorders

To investigate the cognitive functioning of children and adolescents with bipolar illness, 112 child and adolescent psychiatric inpatients and day-hospital patients at a state psychiatric hospital were administered the Wechsler Intelligence Scale for Children–III (WISC–III) as part of an admission psychological assessment. There were 22 patients with Bipolar Disorder and 90 with other psychiatric disorders; all were between 8 and 17 years of age. The patients with Bipolar Disorder had a mean age of 14 yr., a mean Verbal IQ of 78, a mean Performance IQ of 76, and a mean Full Scale IQ of 75. When their WISC–III scores were compared with those who had Schizophrenia Spectrum disorders (Schizophrenia and Schizoaffective Disorder), Psychosis Not Otherwise Specified, Attention Deficit Hyperactivity Disorder, and Conduct Disorder and Oppositional Defiant Disorder, there were no significant between-group mean differences for Verbal IQ, but patients with Bipolar Disorder had a significantly lower mean Performance IQ than those with ADHD and those with Conduct Disorder and Oppositional Defiant Disorder. Contrary to the expectation that the patients with Bipolar Disorder might have better sustained attention (higher Digit Span scores) than those with Schizophrenia Spectrum disorders and worse visual processing speed (lower Coding scores) than the other diagnostic groups, the bipolar patients' Digit Span and Coding scores did not differ significantly from those of the other groups. The patients with Psychosis, Not Otherwise Specified had significantly lower mean Performance IQ, Full Scale IQ, and Coding than the ADHD and the Conduct Disorder and Oppositional Disorder groups.

Biological aspects and candidate biomarkers for psychotic bipolar disorder: A systematic review

AIM

We carried out a systematic review of the available literature about potential biomarkers of psychotic bipolar disorder (BD-P), a specific subset presenting worse outcome and greater risk of relapse than non-psychotic bipolar disorder (BD-NP).

METHODS

We searched the main psychiatric databases (PubMed, ISI Web of Knowledge, PsychInfo). Only original articles with the main topic of BD-P compared to schizophrenia/BD-NP/healthy controls (HC) written in English from 1994 to 2015 were included.

RESULTS

BD-P patients presented higher kynurenic acid levels in the cerebrospinal fluid, elevated anti- S accharomyces cerevisiae antibodies levels, and lower serum levels of dehydroepiandrosterone sulfate and progesterone than BD-NP/HC. Event-related potentials abnormalities have been identified in BD-P with respect to BD-NP. BD-P patients also presented bigger ventricles but similar hippocampal volumes compared to BD-NP/HC. Although the results are contrasting, some cognitive deficits seemed to be related to the psychotic dimension of bipolar affective disorder, such as impairment in verbal/logical memory, working memory, verbal and semantic fluency and executive functioning. Finally, polymorphisms of genes, such as NRG1, 5HTTLPR (s), COMT, DAOA and some chromosome regions (16p12 and 13q), were positively associated with BD-P.

CONCLUSION

Data about the identification of specific biomarkers for BD-P are promising, but most of them have not yet been replicated. They could lead the clinicians to an early diagnosis and proper treatment, thus ameliorating outcome of BD-P and reducing the biological changes associated with a long duration of illness. Further studies with bigger samples are needed to detect more specific biological markers of the psychotic dimension of bipolar affective disorder.

The Longitudinal Course of Schizophrenia Across the Lifespan: Clinical, Cognitive, and Neurobiological Aspects

Despite several decades of research, our knowledge of the long-term course of schizophrenia (SZ) is hampered by a lack of homogeneity of both research methods and phenotypic definitions of SZ's course. We provide a comprehensive review of the course of SZ by applying stringent methodological and diagnostic study-selection criteria. We report on positive and negative symptoms, cognition, and findings obtained by neuroimaging. In addition, we perform a meta-analysis of longitudinal studies of cognition in humans. We selected 35 human studies focusing on a narrow SZ phenotype, employing a follow-up duration of six months or more and consistent methodology at the different measurement points. For the meta-analysis on global cognitive change, eight and four studies were used to compare SZ to healthy and psychiatric controls, respectively. We find that the course of SZ is characterized by a constancy or even improvement of positive and negative symptoms and by fairly stable cognitive impairment, reflecting structural frontal and temporal cortical pathology. Progressive changes of the frontal cortex appear to develop in parallel with changes in symptomatology and executive impairment. Despite stable differences in cognition between patients and controls over the time intervals studied, high heterogeneity in the magnitude of effect sizes is present, and age is identified as one of its potential sources. Meta-regression shows these magnitudes to depend on the age at study inclusion. For future research, a combination of longitudinal and cross-sectional research designs is warranted to better account for potential cohort effects.

Meta-analysis of Cognitive Impairment in First-Episode Bipolar Disorder: Comparison With First-Episode Schizophrenia and Healthy Controls

Neurocognitive deficits are evident both in established schizophrenia and bipolar disorder (BP). However, it has been suggested that schizophrenia, but not BP, is characterized by neurodevelopmental abnormalities that can lead to cognitive deficits at the earliest stages of the illness. The aim of this meta-analytic review was to compare neurocognitive deficits in first-episode BP (FEBP) with healthy controls and first-episode schizophrenia (FES) patients. The current meta-analysis included a total of 22 adult studies and involved comparisons of 533 FEBP patients with 1417 healthy controls and 605 FEBP and 822 FES patients. FEBP patients were significantly impaired in all cognitive domains (d = 0.26-0.80) and individual tasks (d = 0.22-0.66) investigated. FES patients significantly underperformed FEBP patients in most cognitive domains (d = 0.05-0.63) and on individual tasks (d = 0.13-0.77). Neuropsychological impairment, which is comparable to chronic BP, was evident in FEBP. Similar to chronic patients, cognitive functions in FEBP lie intermediate between FES and healthy controls. Neurodevelopmental factors are likely to play a significant role not only in schizophrenia but also in BP.

Comparison of cognitive deficits among drug-naive patients with schizophrenia and major depressive disorder

BACKGROUND

Cognitive deficits have been well-established among patients with severe mental illness. The aim of this study was to clarify the patterns of cognitive deficits in drug-naive patients with schizophrenia and non-psychotic major depressive disorder (MDD) as compared with controls.

METHODS

Thirty drug-naïve participants with schizophrenia, 30 counterparts with non-psychotic MDD, and 30 age-, sex-, and education years-matched healthy controls were recruited. Neuropsychological tests, including the Wisconsin Card Test (WCST), the Continuous Performance Test (CPT) and the Finger Tapping Test (FTT), were administered.

RESULTS

Patients with schizophrenia performed more poorly than the patients with MDD and the normal controls in the WCST. The patients with schizophrenia and the patients with MDD both performed more poorly than the normal controls in the CPT. The patients with MDD also performed more poorly than the normal controls in the FTT.

LIMITATIONS

The age of onset of MDD in this study was younger than in previous reports. The cross-sectional design, small sample sizes, and limited numbers of neuropsychological domains in this study are all obstacles to making a clear causal conclusion.

CONCLUSIONS

These results revealed a distinct pattern of neurocognitive dysfunction among drug-naive patients with schizophrenia and MDD, which may imply different underlying neurobiological mechanisms in schizophrenia and MDD.

The neurocognitive functioning in bipolar disorder: a systematic review of data

BACKGROUND

During the last decades, there have been many different opinions concerning the neurocognitive function in Bipolar disorder (BD). The aim of the current study was to perform a systematic review of the literature and to synthesize the data in a comprehensive picture of the neurocognitive dysfunction in BD.

METHODS

Papers were located with searches in PubMed/MEDLINE, through June 1st 2015. The review followed a modified version of the recommendations of the Preferred Items for Reporting of Systematic Reviews and Meta-Analyses statement.

RESULTS

The initial search returned 110,403 papers. After the deletion of duplicates, 11,771 papers remained for further evaluation. Eventually, 250 were included in the analysis.

CONCLUSION

The current review supports the presence of a neurocognitive deficit in BD, in almost all neurocognitive domains. This deficit is qualitative similar to that observed in schizophrenia but it is less severe. There are no differences between BD subtypes. Its origin is unclear. It seems it is an enduring component and represents a core primary characteristic of the illness, rather than being secondary to the mood state or medication. This core deficit is confounded (either increased or attenuated) by the disease phase, specific personal characteristics of the patients (age, gender, education, etc.), current symptomatology and its treatment (especially psychotic features) and long-term course and long-term exposure to medication, psychiatric and somatic comorbidity and alcohol and/or substance abuse.

Impairments of working memory in schizophrenia and bipolar disorder: the effect of history of psychotic symptoms and different aspects of cognitive task demands

Comparisons of cognitive impairments between schizophrenia (SZ) and bipolar disorder (BPD) have produced mixed results. We applied different working memory (WM) measures (Digit Span Forward and Backward, Short-delay and Long-delay CPT-AX, N-back) to patients with SZ (n = 23), psychotic BPD (n = 19) and non-psychotic BPD (n = 24), as well as to healthy controls (HC) (n = 18) in order to compare the level of WM impairments across the groups. With respect to the less demanding WM measures (Digit Span Forward and Backward, Short-delay CPT-AX), there were no between group differences in cognitive performance; however, with respect to the more demanding WM measures (Long-delay CPT-AX, N-back), we observed that the groups with psychosis (SZ, psychotic BPD) did not differ from one another, but performed poorer than the group without a history of psychosis (non-psychotic BPD). A history of psychotic symptoms may influence cognitive performance with respect to WM delay and load effects as measured by Long-delay CPT-AX and N-back tests, respectively. We observed a positive correlation of WM performance with antipsychotic treatment and a negative correlation with depressive symptoms in BPD and with negative symptoms in SZ subgroup. Our study suggests that WM dysfunctions are more closely related to a history of psychosis than to the diagnostic categories of SZ and BPD described by psychiatric classification systems.

Common and disease-specific dysfunctions of brain systems underlying attentional and executive control in schizophrenia and bipolar disorder

Schizophrenia and bipolar disorder broadly overlap in multiple areas involving clinical phenomenology, genetics, and neurobiology. Still, the investigation into specific elementary (sub-)processes of executive functioning may help to define clear points of distinction between these categorical diagnoses to validate the nosological dichotomy and, indirectly, to further elucidate their pathophysiological underpinnings. In the present behavioral study, we sought to separate common from diagnosis-specific deficits in a series of specific elementary sub-functions of executive processing in patients with schizophrenia and bipolar disorder. For our purpose, we administered a modern and multi-purpose neuropsychological task paradigm to equal-sized and matched groups of schizophrenia patients, patients with bipolar disorder, and healthy control subjects. First, schizophrenia patients compared to the bipolar group exhibited a more pronounced deficit in general measures of task performance comprising both response speed and accuracy. Additionally, bipolar patients showed increased advance task preparation, i.e., were better able to compensate for response speed deficits when longer preparation intervals were provided. Set-shifting, on the other hand, was impaired to a similar degree in both patient groups. Finally, schizophrenia patients exhibited a specific deficit in conflict processing (inhibitory control) and the shielding of task-relevant processing from distraction (i.e., attentional maintenance). The present investigation suggests that specific neuropsychological measures of elementary executive functions may represent important points of dissociation between schizophrenia and bipolar disorder, which may help to differentiate the pathophysiological underpinnings of these major psychiatric disorders. In this context, the present findings highlight the measures of inhibitory control and attentional maintenance as promising candidates.

Generalized and specific neurocognitive deficits in psychotic disorders: utility for evaluating pharmacological treatment effects and as intermediate phenotypes for gene discovery

A growing body of research suggests that schizophrenia and bipolar disorder share overlapping clinical, neurobiological, and genetic features, raising important questions about the boundaries and distinctiveness of these 2 major psychiatric disorders. A generalized cognitive impairment has long been understood to be a core feature of schizophrenia. More recently, it has become apparent that cognitive impairment also occurs in bipolar disorder, particularly in those patients with a history of psychotic symptoms. Whether a generalized deficit exists across a spectrum of psychotic disorders is less clearly established. Additionally, in the context of a broad impairment, it remains a significant challenge to identify deficits in specific cognitive processes that may have distinct neurochemical or regional brain substrates and linkages to particular risk-associated genetic factors. In this article, we review the findings from neuropsychological studies across a spectrum that includes schizophrenia, schizoaffective and bipolar disorders, and conclude the available evidence strongly supports that a generalized deficit is present across psychotic disorders that differs in severity more so than form. We then consider the implications of generalized and specific deficits in psychosis for 2 areas of research--the evaluation of pharmacological treatments targeting cognitive deficits, and the investigation of cognitive intermediate phenotypes in family genetic studies. Examples from the literature that touch on the relevance of the generalized deficit in these contexts are provided, as well as consideration for the continued need to identify specific impairments that are separable from the generalized deficit in order to advance drug and gene discovery.

Cognitive compromise in bipolar disorder with chronic cannabis use: cause or consequence?

This article briefly reviews the neuropsychological deficits associated with bipolar disorder and examines how substance abuse, in particular chronic cannabis use, may contribute to these. The focus of the article is cannabis, owing to its popularity in patients with bipolar disorder, although many studies focus on its use in conjunction with other substances. The findings are contextualized within bipolar disorder, examining functional outcome.

A comparison of cognitive functioning in acute schizophrenia and depression

OBJECTIVE

Even though cognitive deficits are well recognised in schizophrenia and depression, direct comparisons between the disorders are scarce in literature. This study aims to assess specificity and degree of cognitive deficits in inpatients with acute schizophrenia and unipolar major depression.

METHODS

A neuropsychological test battery was administered to 76 schizophrenic patients, 102 patients with unipolar major depression and 85 healthy controls (HCs), assessing verbal learning [Rey Auditory Verbal Learning Test (RAVLT)], processing speed (Trail Making Test), verbal fluency and visual memory (Wechsler Memory Scale-Revised test).

RESULTS

Both patient groups were significantly impaired compared with HCs with regard to all test outcomes. The schizophrenia group (SG) performed significantly worse in the Wechsler Memory Scale and verbal fluency than the depression group (DG). The DG reached significantly lower scores than the SG in the RAVLT delayed recall subtest. No significant group difference between SG and DG was found for the Trail Making Test and the RAVLT direct recall trails.

CONCLUSION

Our results indicate that cognitive impairment is present in both disorders. Schizophrenic patients performed worse than patients with unipolar depression in only two of the administered tests. Differences in cognitive performance between the groups are not as general as often assumed. Therefore, during the acute phase of illness, a diagnostic classification on the grounds of the patients' neurocognitive performance has to be done with caution.

Education and employment levels among Jamaican patients newly diagnosed with schizophrenia and bipolar disorder

BACKGROUND

Comparisons between persons with bipolar disorder and those with schizophrenia are not well researched in the Caribbean.

AIMS

To compare the educational and occupational attainments in Jamaicans diagnosed with these two disorders.

METHODS

Data on diagnosis, educational level, type of employment and other basic socio-demographic variables were collected from Jamaican hospital patients who were newly diagnosed with schizophrenia or bipolar disorder. Fisher's exact and χ2 tests, as well as binary logistic regression, were used to explore how these characteristics varied according to diagnosis. Statistical significance was taken at p < .05.

RESULTS

Schizophrenia was associated with significantly lower educational attainment than bipolar disorder (p = .022 for educational level attained; p = .026 for completion of secondary school). The majority (87.1%) of the 93 patients included in the analysis had no specific marketable job skills. However, the proportion of persons with bipolar disorder who had such skills was three times the corresponding proportion of persons with schizophrenia.

CONCLUSIONS

The low educational achievement among persons with schizophrenia makes education a potentially important area for interventions targeted at this group. Because gross deficiencies in job skills were common to both patient groups, improvement in job skill levels is an important goal for persons with either of these disorders.

Lifetime depressive disorders and adherence to anti-retroviral therapy in HIV-infected Ugandan adults: a case-control study

BACKGROUND

There is limited information on the impact of lifetime depressive disorders on adherence to ART.

AIM

We examined the association between lifetime depressive disorders and adherence to anti-retroviral therapy (ART) among a rural clinic-based HIV positive population. We further explored whether this association was mediated by current depression and moderated by gender.

METHODS

Two hundred HIV positive individuals who had<95% adherence and two hundred HIV positive individuals who had ≥95% adherence were screened for depression using the self-reporting questionnaire (SRQ-20) and evaluated with the Mini neuropsychiatric interview (MINI). Multivariate logistic regression was used to assess the association between lifetime depressive disorders and adherence to ART. The logistic regression model of Baron and Kenny was used to evaluate the mediating effect of current depression. Hierarchical binomial logistic regression was used to evaluate the moderating effect of gender.

RESULTS

HIV positive individuals with lifetime depressive disorders had an increased risk of non-adherence to ART after controlling for education status, income, self-efficacy, perceived social support, cognitive impairment and current alcohol use disorders [AOR=1.68, 95%CI (1.02-2.79), p=0.04]. This association was stronger in females than males [AOR= 4.76, 95%CI (1.52-14.97), p=0.008].

LIMITATIONS

Findings cannot be generalized to ART naïve individuals or those using ART for less than six months.

CONCLUSION

Lifetime depressive disorders are associated with increased risk of non-adherence to ART in rural women with HIV infection in southern Uganda. Detection and treatment of depression can potentially improve adherence with HIV treatment in this setting.

Functional impairment in people with schizophrenia: focus on employability and eligibility for disability compensation

BACKGROUND

The Social Security Administration (SSA) is considering whether schizophrenia may warrant inclusion in their new "Compassionate Allowances" process, which aims to identify diseases and other medical conditions that invariably quality for Social Security disability benefits and require no more than minimal objective medical information. This paper summarizes evidence on the empirical association between schizophrenia and vocational disability. A companion paper examines the reliability and validity of schizophrenia diagnosis which is critically relevant for granting a long-term disability on the basis of current diagnosis.

METHODS

This is a selective literature review and synthesis, based on a work plan developed in a meeting of experts convened by the National Institute of Mental Health and the SSA. This review of the prevalence of disability is focused on the criteria for receipt of disability compensation for psychotic disorders currently employed by the SSA.

RESULTS

Disability in multiple functional domains is detected in nearly every person with schizophrenia. Clinical remission is much more common than functional recovery, but most patients experience occasional relapses even with treatment adherence, and remissions do not predict functional recovery. Under SSA's current disability determination process, approximately 80% of SSDI/SSI applications in SSA's diagnostic category of "Schizophrenia/Paranoid Functional Disorders" are allowed, compared to around half of SSDI/SSI applications overall. Moreover, the allowance rate is even higher among applicants with schizophrenia. Many unsuccessful applicants are not denied, but rather simply are unable to manage the process of appeal after initial denials.

DISCUSSION

Research evidence suggests that disability applicants with a valid diagnosis of schizophrenia have significant impairment across multiple dimensions of functioning, and will typically remain impaired for the duration of normal working ages or until new interventions are developed.

Beyond the broken error-related negativity: functional and diagnostic correlates of error processing in psychosis

BACKGROUND

Studies of event-related potentials have consistently shown that schizophrenia is associated with a blunted error-related negativity (ERN), indicating a deficit in error monitoring. It is unknown whether this deficit is unique to schizophrenia or is common to psychotic disorders more broadly, and its associations with clinical characteristics of the illness are not well understood.

METHODS

The ERN and the error positivity (Pe) were recorded from 33 individuals with schizophrenia, 45 individuals with other psychotic disorders, and 33 healthy control subjects. Patients were drawn from a cohort with psychotic disorders followed since first hospitalization and diagnosed by consensus based on 10 years of observation.

RESULTS

The ERN was profoundly blunted in the patient group, regardless of diagnosis, indicating that this deficit is not unique to schizophrenia. The Pe, meanwhile, was blunted only among individuals with schizophrenia, indicating that the ERN and Pe are differentially related to psychotic illnesses. A blunted ERN was associated with more severe negative symptoms and poorer real-world functioning, as indicated by unemployment and re-hospitalization over 10 years of illness. Although reduced compared with control subjects, ERN amplitude was greater in patients with higher neuroticism, indicating that error processing is moderated by personality differences in the same manner as in healthy populations.

CONCLUSIONS

The current study advances the literature by evaluating diagnostic specificity and functional correlates of impaired error processing in psychosis.

Can genetics inform the management of cognitive deficits in schizophrenia?

There is no doubt that schizophrenia has a significant genetic component and a number of candidate genes have been identified for this debilitating disorder. Of note, several of these are implicated in cognition. Cognitive deficits constitute core symptoms of schizophrenia, and while current antipsychotic treatment strategies aim to help psychosis-related symptomatology, the cognitive symptom domain is largely inadequately treated. A number of other pharmacological approaches (e.g. using drugs that target specific neurotransmitter systems) have also been attempted for the amelioration of cognitive deficits in this population; however, these too have had limited success so far. Psychological interventions appear promising, though there has been speculation regarding whether or not these produce long-term functional improvements. Pharmacogenetic studies of the cognitive effects of currently available antipsychotics, although in relatively early stages, suggest that the treatment of cognitive deficits in schizophrenia may be advanced by focusing on genetic variants associated with specific cognitive dysfunctions in the general population and using this to match the most relevant pharmacological and/or psychological interventions with the genetic and cognitive profiles of the target population. Such a strategy would encourage bottom-up advances in drug development and provide a platform for individualised treatment of cognitive deficits in schizophrenia.

Dissociable and common deficits in inhibitory control in schizophrenia and bipolar disorder

Current research focuses on delineating the neurobiological boundaries between familial risk for schizophrenia (SZ) and bipolar disorder (BD). Available evidence suggests that inhibitory control may be affected in both disorders. Inhibitory control relies on the dual processes of contextual information maintenance and response inhibition. This study investigated the effect of familial risk of SZ or BD on these two aspects of inhibitory control. Seventeen healthy first-degree relatives of patients with BD (BD-R), 15 healthy relatives of patients with SZ (SZ-R) and 23 demographically matched controls were compared in terms of their performance during Controlled Oral Word Association (COWA), which measures contextually driven response selection, and during the Hayling Sentence Completion Test (HSCT), which assesses contextual response selection and inhibition. Compared to controls and BD-R, SZ-R showed deficits in contextual information processing that resulted in spontaneous errors in the COWA as well as deficits in response inhibition during the HSCT that resulted in higher error rates. BD-R also showed deficits in response inhibition during the HSCT relative to controls, which were, however, less pronounced than for SZ-R. Both relatives groups had longer response times. Our results suggest that failure in contextual maintenance is primarily associated with familial risk for SZ, while response inhibition may be a shared marker of familial risk for both disorders.

Relationship of neurocognitive deficits to diagnosis and symptoms across affective and non-affective psychoses

INTRODUCTION

Neurocognitive dysfunction is believed to be a core feature of schizophrenia and is increasingly recognized as a common symptom dimension in bipolar disorder. Despite a copious literature on neurocognition in these disorders, the relationship amongst neurocognition, symptoms, and diagnosis remains unclear. We examined neurocognitive functioning in a cross-diagnostic sample of patients with psychotic disorders. Based on previous findings, it was hypothesized that neurocognitive functioning would be impaired in all three patient groups, and that groups would be similarly impaired on all neuropsychological measures. Additionally, we predicted that negative symptoms but not positive, general, or mood symptoms, would be associated with neurocognitive functioning.

METHOD

Neurocognitive functioning and symptoms were assessed in participants with schizophrenia (n=25), schizoaffective disorder (n=29), or bipolar disorder with psychosis (n=31), and in healthy controls (n=20).

RESULTS

Neurocognitive functioning was significantly impaired in all patient groups, and groups did not differ by diagnosis on most measures. A series of linear regressions revealed that negative symptoms (but no other clinical symptom) predicted poorer executive functioning across groups. Diagnosis was not a significant predictor of any neurocognitive variable.

DISCUSSION

Neurocognitive deficits were pronounced in this cross-diagnostic sample of patients with psychotic disorders, and did not differ by diagnosis. Neurocognitive dysfunction may represent a symptom dimension that spans diagnostic categories, and may reflect shared pathogenic processes. As neurocognitive dysfunction is among the strongest predictors of outcome in patients, efforts to treat these deficits, which have shown promise in schizophrenia, should be extended to all patients with psychosis.

Prevalence and factors associated with depressive disorders in an HIV+ rural patient population in southern Uganda

BACKGROUND

Depressive disorders are estimated to occur in nearly half of HIV-infected individuals worldwide.

AIM

To examine the prevalence and cardinal demographic, psychosocial and clinical features associated with having any depressive disorder, sub-clinical depression, current and lifetime depressive disorders among patients with human immunodeficiency virus (HIV) in southern Uganda.

METHODS

Five hundred HIV+ individuals were screened for depression using a 20 item self-reporting questionnaire (SRQ-20) and evaluated with the mini neuropsychiatric interview(MINI) that assessed current and lifetime depressive disorders.

RESULTS

The prevalence estimates of any depressive disorder, subclinical depression, both current and lifetime major depression, and bipolar depression were 46.4%, 17.8%, 25% and 3.6% respectively. In comparison to non-depressed patients, those with sub-clinical depression were less likely to have high levels of self-efficacy, more likely to be using ART for less than one year, have advanced HIV disease and current alcohol use disorders (AUD's). Those with both current and lifetime depressive disorders were less likely to be 85% adherent to antiretroviral therapy (ART), have social support and high levels of self-efficacy, more likely to have tuberculosis and past manic episodes. Those with only lifetime depressive disorders were more likely to have current AUD's and past manic episodes.

LIMITATIONS

Information concerning exposures and outcomes was collected simultaneously, thus causal relationships are difficult to establish.

CONCLUSIONS

Sub-clinical depression, major depression and bipolar depression are widespread among HIV patients receiving ART. Integration of mental health services into HIV Care is desperately needed.

Evolution of neuropsychological dysfunction during the course of schizophrenia and bipolar disorder

BACKGROUND

Neurocognitive dysfunction in schizophrenia (SZ), bipolar (BD) and related disorders represents a core feature of these illnesses, possibly a marker of underlying pathophysiology. Substantial overlap in domains of neuropsychological deficits has been reported among these disorders after illness onset. However, it is unclear whether deficits follow the same longitudinal pre- and post-morbid course across diagnoses. We examine evidence for neurocognitive dysfunction as a core feature of all idiopathic psychotic illnesses, and trace its evolution from pre-morbid and prodromal states through the emergence of overt psychosis and into chronic illness in patients with SZ, BD and related disorders.

METHOD

Articles reporting on neuropsychological functioning in patients with SZ, BD and related disorders before and after illness onset were reviewed. Given the vast literature on these topics and the present focus on cross-diagnostic comparisons, priority was given to primary data papers that assessed cross-diagnostic samples and recent meta-analyses.

RESULTS

Patients with SZ exhibit dysfunction preceding the onset of illness, which becomes more pronounced in the prodrome and early years following diagnosis, then settles into a stable pattern. Patients with BD generally exhibit typical cognitive development pre-morbidly, but demonstrate deficits by first episode that are amplified with worsening symptoms and exacerbations.

CONCLUSIONS

Neuropsychological deficits represent a core feature of SZ and BD; however, their onset and progression differ between diagnostic groups. A lifetime perspective on the evolution of neurocognitive deficits in SZ and BD reveals distinct patterns, and may provide a useful guide to the examination of the pathophysiological processes underpinning these functions across disorders.

Patterns of attentional deficits and emotional bias in bipolar and major depressive disorder

OBJECTIVES

Previous studies have reported deficits in selective attention and specific emotional biases in patients with bipolar (BP) disorder. The extent to which these distinguish BP patients from those with major depressive disorder (MDD) remain unclear. We aimed to examine the relationship between selective attentional impairments and emotional biases in symptomatic and euthymic BP, and symptomatic MDD patients.

DESIGN

A between-group design was used. The time taken for BP patients to perform on Stroop tasks was compared with that in patients with MDD, and a normal healthy control group.

METHODS

BP patients during manic (N = 14) and depressed (N = 13) episodes, and euthymia (N = 15), together with symptomatic patients with MDD (N = 17) and normal healthy controls (N = 18) were matched for IQ, gender, and age. Selective attention was measured using the Golden (1978) version of the Stroop task, and emotional bias, using the Lyon, Startup, and Bentall (1999) version of the emotional Stroop task.

RESULTS

On the Card Stroop, all patients were significantly slower than normal healthy controls on all three conditions. On the emotional Stroop Test, all patients were slower on neutral, positive, and negative conditions.

CONCLUSIONS

Our findings suggest that both BP and MDD patients demonstrate impaired performance on neutral and emotionally salient attentionally demanding tasks. The finding of impaired performance in all patients on baseline conditions in each task, however, indicates the need for inclusion of additional baseline conditions in these tasks in order to elucidate the nature of attentional impairments specific to these patient populations.

Cognitive functioning in subjects with recent-onset psychosis from a low-middle-income environment: multiple-domain deficits and longitudinal evaluation

Cognitive deficits are a key feature of recent-onset psychosis, but there is no consensus on whether such deficits are generalized or confined to specific domains. Besides, it is unclear whether cognitive deficits: a) are found in psychotic patients in samples from outside high-income countries; and b) whether they progress uniformly over time in schizophrenia and affective psychoses. We applied 12 tests organized into eight cognitive domains, comparing psychosis patients (n = 56, time from initial contact = 677.95+/-183.27 days) versus healthy controls (n=70) recruited from the same area of São Paulo, Brazil. Longitudinal comparisons (digit span and verbal fluency) were conducted between a previous assessment of the subjects carried out at their psychosis onset, and the current follow-up evaluation. Psychosis patients differed significantly from controls on five domains, most prominently on verbal memory. Cognitive deficits remained detectable in separate comparisons of the schizophrenia subgroup and, to a lesser extent, the affective psychosis subjects against controls. Longitudinal comparisons indicated significant improvement in schizophrenia, affective psychoses, and control subjects, with no significant group-by-time interactions. Our results reinforce the view that there are generalized cognitive deficits in association with recent-onset psychoses, particularly of non-affective nature, which persist over time.

Is perseveration uniquely characteristic of schizophrenia?

Evidence for the existence of categorically distinct disorders such as schizophrenia, bipolar disorder, and major depression is mixed: neuropsychological impairments may be similar in schizophrenia and bipolar disorder; schizophrenia and major depression show similar neuropsychological and frontal lobe disturbances; and overlap in biochemical anomalies among the disorders has also been reported. Interestingly, there are very few studies that directly compare all diagnoses. The present study compares cognitive perseveration in these three diagnostic groups using the Wisconsin Card Sorting Task (WCST) to examine performance across patients with schizophrenia (n=143), bipolar disorder (n=25) and major depression (n=21). Individuals used in this sample were 18-45 years old at time of testing to eliminate confounds of aging. Sex ratios within each diagnostic group are comparable to those of the national population. Univariate analyses examining diagnostic group and percent perseverative error revealed no significant differences in WCST performance across the diagnostic groups. Examination of clinical variables in the sample of individuals with schizophrenia revealed that perseveration is related to negative symptoms and depressive symptoms in young adults.

Cognitive impairment of executive function as a core symptom of schizophrenia

Cognitive dysfunction is a common finding in schizophrenia. Nevertheless the specific pattern of neuropsychological impairment in schizophrenia compared to other severe mental illnesses has not been intensively studied. Twenty-four patients with schizophrenia belonging to different stages of the disease (11 first-episode patients, 13 patients with multiple episodes), 18 patients with bipolar disorder and 23 healthy control subjects underwent standardized neuropsychological assessment. Statistical analysis of covariance (ANCOVA) demonstrated that, compared to control subjects, patients with schizophrenia performed significantly worse in the trail-making test (P = 0.012), verbal fluency (category letter, P = 0.004), verbal learning/memory (P = 0.005), and the Wisconsin Card Sorting Test (WCST) (P = 0.004 for administered trials; P = 0.025 for perseverative responses, T value) indicating significant deficits in attention and psychomotor performance, and in particular in verbal working memory and cognitive flexibility for schizophrenic patients. A significant difference between schizophrenic and bipolar patients was found only in the WCST. Schizophrenic patients made significantly more perseverative responses (P = 0.002, ANCOVA), indicating a more pronounced and specific deficit in cognitive flexibility and frontally based executive function. In conclusion, these results may suggest a cognitive endophenotype in schizophrenia and underline the role of the prefrontal cortex in schizophrenic pathophysiology.

Cognitive impairment in affective psychoses: a meta-analysis

It has recently been suggested that cognitive impairment should be included in the diagnostic criteria of schizophrenia. One of the main arguments in support of this suggestion has been the hope that cognitive impairment can help distinguish schizophrenia from bipolar disorder (BD). However, recent evidence shows that cognitive deficits occur in BD and persist beyond euthymia. Further, mood disorders with psychotic features might be expected to manifest greater cognitive impairment, which further complicates the potential to differentiate these disorders. The goal of the current meta-analysis was to examine the magnitude and characteristics of cognitive impairments in affective psychoses (AP). A systematic search of the existing literature sourced 27 studies that met the inclusion criteria. These studies compared cognitive performances of 763 patients with AP (550 BD and 213 major depressive disorder) and 1823 healthy controls. Meta-regression and subgroup analyses were used to examine the effects of moderator variables. Meta-analyses of these studies showed that patients with AP were impaired in all 15 cognitive tasks with large effect sizes for most measures. There were no significant differences between the magnitude of impairments between the BD and major depressive disorder groups. The largest effect size was found for symbol coding, stroop task, verbal learning, and category fluency, reflecting impairments in elementary and complex aspects of attentional processing, as well as learning and memory. In general, the pattern of cognitive impairments in AP was similar to reported findings in euthymic patients with BD, but relatively more pronounced.

Cognitive functioning in schizophrenia, schizoaffective disorder and affective psychoses: meta-analytic study

BACKGROUND

Cognitive functioning in affective psychosis and schizoaffective disorder is much less studied compared with schizophrenia.

AIMS

To quantitatively undertake a meta-analysis of the available data that directly compares cognitive functioning across schizophrenia, schizoaffective disorder and affective psychosis.

METHOD

Following a thorough literature review, 31 studies that compared the performances of people with schizophrenia (1979 participants) with that of those with affective psychosis or schizoaffective disorder (1314 participants) were included. To determine the effect of demographic and clinical confounders, meta-regression and subgroup analyses were conducted.

RESULTS

In 6 of 12 cognitive domains, people with schizophrenia performed worse than people with schizoaffective disorder or affective psychosis. However, the between-group differences were small and the distribution of effect sizes showed substantial heterogeneity. The between-group differences were driven by a higher percentage of males, more severe negative symptoms and younger age at onset of illness in the schizophrenia samples.

CONCLUSIONS

Neuropsychological data do not provide evidence for categorical differences between schizophrenia and other groups. However, a subgroup of individuals with schizophrenia who have more severe negative symptoms may be cognitively more impaired than those with affective psychosis/schizoaffective disorder.

A comparison of neuropsychological dysfunction in first-episode psychosis patients with unipolar depression, bipolar disorder, and schizophrenia

The severity and profile of cognitive dysfunction in first episode schizophrenia and psychotic affective disorders were compared before and after antipsychotic treatment. Parallel recruitment of consecutively admitted study-eligible first-episode psychotic patients (30 schizophrenia, 22 bipolar with psychosis, and 21 psychotic depression) reduced confounds of acute and chronic disease/medication effects as well as differential treatment and course. Patient groups completed a neuropsychological battery and were demographically similar to healthy controls (n=41) studied in parallel. Prior to treatment, schizophrenia patients displayed significant deficits in all cognitive domains. The two psychotic affective groups were also impaired overall, generally performing intermediate between the schizophrenia and healthy comparison groups. No profile differences in neuropsychological deficits were observed across patient groups. Following 6 weeks of treatment, no patient group improved more than practice effects seen in healthy individuals, and level of performance improvement was similar for affective psychosis and schizophrenia groups. Although less severe in psychotic affective disorders, similar profiles of generalized neuropsychological deficits were observed across patient groups. Recovery of cognitive function after clinical stabilization was similar in mood disorders and schizophrenia. To the extent that these findings are generalizable, neuropsychological deficits in psychotic affective disorders, like schizophrenia, may be trait-like deficits with persistent functional implications.

Neuropsychological function and dysfunction in schizophrenia and psychotic affective disorders

BACKGROUND

Mounting evidence suggests that compromised neurocognitive function is a central feature of schizophrenia. There are, however, schizophrenia patients with a normal neuropsychological (NP) performance, but estimates of the proportion of NP normal patients vary considerably between studies. Neurocognitive dysfunction is also a characteristic of other psychotic disorders, yet there are inconsistencies in the literature regarding the similarity to impairments in schizophrenia. NP normality in psychotic affective disorders has not been systematically studied.

METHODS

Data came from the Suffolk County Mental Health Project, an epidemiological study of first-admission patients with psychotic disorders. Respondents with a diagnosis of schizophrenia (N = 94) or schizoaffective disorder (N = 15), bipolar disorder (N = 78), and major depressive disorder (N = 48) were administered a battery of NP tests assessing 8 cognitive domains 2 years after index admission. Patients' performance profile was compared, and their NP status was classified based on 3 previously published criteria that vary in their stringency.

RESULTS

The 4 diagnostic groups had comparable NP performance profile patterns. All groups demonstrated impairments in memory, executive functions, and attention and processing speed. However, schizophrenia patients were more impaired than the other groups on all cognitive domains. Results were not attenuated when IQ was controlled. Prevalence of NP normality ranged between 16% and 45% in schizophrenia, 20% and 33% in schizoaffective disorder, 42% and 64% in bipolar disorder, and 42% and 77% in depression, depending on the criterion employed.

CONCLUSIONS

Evidence suggests that differences in NP performance between schizophrenia and psychotic affective disorders are largely quantitative. NP impairment is also common in psychotic affective disorders. A significant minority of schizophrenia patients are NP normal.

Selective deficits in semantic verbal fluency in patients with a first affective episode with psychotic symptoms and a positive history of mania

OBJECTIVES

Neurocognitive dysfunction is likely to represent a trait characteristic of bipolar disorder, but the extent to which it comprises 'core' deficits as opposed to those secondary to longstanding illness or intellectual decline is unclear. We investigated neuropsychological performance in an epidemiologically derived sample of patients with a first affective episode with psychotic symptoms and a positive history of mania, compared to community controls.

METHODS

Using a nested case-control, population-based study, measures of episodic and working memory, executive function, processing speed, and visual-spatial perception were compared between 35 patients with a first affective episode with psychotic symptoms and a positive history of mania, and 274 community controls, as well as a subgroup of 105 controls matched on current IQ ('good' versus 'poor') and IQ trajectory ('stable', 'declined', or 'improved') with the patients (three controls per case).

RESULTS

Compared to the extended control sample, probands showed a suggestive deficit in short-term verbal recall, and a significant deficit in semantic fluency. Only the latter was detectable in the comparison with the IQ-matched controls. All other neurocognitive domains showed intact performance or nonsignificant deficits of small effect sizes compared to both control groups. Semantic fluency showed no association with symptoms or duration of untreated illness.

CONCLUSIONS

Patients with a first affective episode with psychotic symptoms and a positive history of mania show an isolated, selective deficit in semantic verbal fluency, against a background of generally preserved neurocognitive function. This pattern seems to contrast with the more widespread neuropsychological dysfunction seen in schizophrenia.

Major psychoses with mixed psychotic and mood symptoms: are mixed psychoses associated with different neurobiological markers?

OBJECTIVE

Evidence related to overlapping clinical and genetic risk factors in schizophrenia and bipolar disorder (BD) have raised concerns about the validity of 'Kraepelinian dichotomy'. As controversies mainly arise in mixed psychoses that occupy the intermediate zone between schizophrenia and BD, investigating neurobiological markers of mixed psychoses may be relevant to understanding the nature of psychotic disorders.

METHOD

In this article, we review studies comparing magnetic resonance imaging, neuropsychological and electrophysiological findings in mixed psychoses with each other, as well as with more prototypical cases of schizophrenia and BD.

RESULTS

The evidence reviewed suggests that mixed psychoses may be associated with different genetic and neurobiological markers compared with prototypical forms of schizophrenia and BD.

CONCLUSION

These findings may be compatible with more sophisticated versions of dimensional and continuum models or, alternatively, they may suggest that there is an intermediate third category between prototypical schizophrenia and BD.

Duration of untreated psychosis and neuropsychological function in first episode psychosis

PURPOSE

We investigated whether duration of untreated psychosis (DUP) prior to first presentation was associated with cognitive function in first episode psychosis (FEP) subjects. We predicted that longer DUP would be associated with greater neurocognitive impairment.

METHOD

180 subjects with schizophrenia (and 93 subjects with Other Psychoses) performed a neurocognitive battery assessing IQ, verbal learning, working memory, visual learning and speed of processing. DUP was defined as the number of days between first onset of psychotic symptoms and first contact with psychiatric services.

RESULTS

Longer DUP was associated with impaired performance in verbal IQ (p=0.04), verbal learning (p=0.02), and verbal working memory (p=0.04) in FEP subjects with schizophrenia. These associations remained significant for verbal IQ when scores were corrected for age, gender, educational level and ethnicity.

CONCLUSIONS

Longer DUP is associated with poorer neurocognitive ability in schizophrenia subjects at time of first presentation. Since this was a cross-sectional study we can not tell whether longer DUP was a cause or a consequence of the poorer performance.

The effect of previous psychotic mood episodes on cognitive impairment in euthymic bipolar patients

OBJECTIVES

Cognitive dysfunctions in several domains were proposed to be trait markers of bipolar patients. The aim of this study was to evaluate the effect of previous psychotic features on neuropsychological measures, including sustained attention, in remitted bipolar patients.

METHODS

The study participants were 40 euthymic psychotic, 25 non-psychotic bipolar I patients and 30 healthy control subjects. Participants were assessed with a battery of neuropsychological tests targeting attention, executive functions, psychomotor speed, verbal learning and memory.

RESULTS

Euthymic psychotic bipolar patients performed worse than controls on most of the measures, after controlling for the confounding effects of education, age and residual symptoms. Non-psychotic patients were also impaired on tasks of attention, fluency and psychomotor speed. 'Number of Wisconsin Card Sorting Test (WCST) categories' achieved was the only measure on which psychotic patients performed significantly worse compared to non-psychotic patients. Differences among patient groups were not explained by illness severity measures. The duration of illness was related to slowness in psychomotor speed tasks. Verbal memory deficits may be related to serum lithium levels and age of onset of disease.

CONCLUSIONS

Deficits in cognitive flexibility may be a candidate for being a trait marker of psychotic features among bipolar patients. However, verbal fluency, psychomotor speed and sustained attention deficits may be candidates for vulnerability indicators of bipolar disorder in general.

Context processing performance in bipolar disorder patients

OBJECTIVES

Context processing is the adaptive control of current behavior through the use of prior context information. It has been found to be impaired in schizophrenia. Some studies have indicated that, compared with patients with schizophrenia, those with bipolar disorder (BPD) display a similar but less severe neuropsychological pattern of impairment. However, this cognitive dimension has not yet been examined in BPD patients in the existing literature.

METHODS

An expectancy version of the AX continuous performance test (AX-CPT) was administered to 15 bipolar outpatients and 26 healthy controls. Patients with schizophrenia, in which context processing deficits are known to occur, were used as a reference group.

RESULTS

Bipolar patients showed a context processing deficit relative to healthy controls, although this was less severe and generalized than in schizophrenia patients.

CONCLUSIONS

These findings suggest there are milder impairments in context processing in BPD compared with schizophrenia. However, the severity of possible context processing deficits in BPD may have been underestimated in our sample of mostly euthymic outpatients.