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

The muscarinic system, cognition and schizophrenia

An increasing body of evidence has implicated the central muscarinic system as contributing to a number of symptoms of schizophrenia and serving as a potential target for pharmaceutical interventions. A theoretical review is presented that focuses on the central muscarinic system's contribution to the cognitive symptoms of schizophrenia. The aim is to bridge the void between pertinent neuropsychological and neurobiological research to provide an explanatory account of the role that the central muscarinic system plays in the symptoms of schizophrenia. First, there will be a brief overview of the relevant neuropsychological schizophrenia literature, followed by a concise introduction to the central muscarinic system. Subsequently, we will draw from animal, neuropsychological and pharmacological literature, and discuss the findings in relation to cognition, schizophrenia and the muscarinic system. Whilst unifying the multiple domains of research into a concise review will act as a useful line of enquiry into the central muscarinic systems contribution to the symptoms of schizophrenia, it will be made apparent that more research is needed in this field.

Neurocognitive functioning of subjects with putative pre-psychotic states and early psychosis

BACKGROUND

The neurocognitive functioning of patients with schizophrenia is likely to decline at the early stage of the illness. More evidence is needed to determine whether deficits in certain domains of neurocognition precede the onset of illness and can predict the onset of psychosis.

METHODS

Subjects were recruited from the SOPRES study in Taiwan. A neuropsychological battery including the continuous performance test, Wisconsin Card Sorting Test, Wechsler Adult Intelligence Scale-Third Edition, Trail Making Tests, Mandarin version of the Verbal Fluency Test, and Wechsler Memory Scale-Third Edition, was applied at baseline and 1-year follow-up. Neurocognitive profiles derived from these tests were categorized into 9 domains for comparisons among subjects with different levels of clinical severity.

RESULTS

A total of 324 participants, including 49 with first episode psychosis (FEP), 53 with ultra-high risk (UHR), 42 with intermediate risk (IR), 43 with marginal risk (MR), and 137 normal controls completed a baseline assessment and 71% of the participants completed a 1-year follow-up assessment. The profiles of the UHR and IR groups were identical at baseline. Those who converted to FEP later on (UHR+) showed relatively poorer performance than non-converters (UHR-) at baseline. At follow-up the performance of UHR+ was compatible to that of FEP, while UHR- generally improved.

CONCLUSIONS

By including subjects with early putative pre-psychotic states, our study clarifies some inconsistencies about the timing and stability of changes in neurocognitive functioning that occur at the start of psychosis; it also raises questions regarding the feasibility of using neurocognitive deficits to predict the risks of transition to psychosis.

Cognitive impairment in first-episode mania: a systematic review of the evidence in the acute and remission phases of the illness

There is evidence of cognitive impairment that persists in the remission phase of bipolar disorder; however, the extent of the deficits that occur from the first onset of the disorder remains unclear. This is the first systematic review on cognitive functioning in the early stages of bipolar I disorder. The aim of the study was to identify the patterns and degree of cognitive impairment that exists from first-episode mania. Three electronic databases (MEDLINE, PsycINFO and PubMed) were systematically searched for studies published from January 1980 to June 2014. Eligible studies were separated into two groups: acute and remission. The Newcastle-Ottawa quality assessment scale was utilised to measure the quality of the included studies. A total of seven studies (three acute and four remission), including 230 first-episode mania and 345 healthy control participants, were eligible for the review. The studies in the acute phase only examined aspects of executive functioning, with impairments identified in cognitive flexibility, though not in response inhibition and verbal fluency relative to healthy controls. The most consistent finding during the remission phase was a deficit in working memory, whereas in the other domains, the findings were equivocal. Non-verbal memory and verbal fluency were not impacted in remission from first-episode mania. In conclusion, deficits are present in some but not all areas of cognitive functioning during the early stages of bipolar I disorder. Further research is warranted to understand the longitudinal trajectory of change from first-episode mania.

Neuropsychological and functional outcomes in recent-onset major depression, bipolar disorder and schizophrenia-spectrum disorders: a longitudinal cohort study

Functional disability is the lead contributor to burden of mental illness. Cognitive deficits frequently limit functional recovery, although whether changes in cognition and disability are longitudinally associated in recent-onset individuals remains unclear. Using a prospective, cohort design, 311 patients were recruited and assessed at baseline. One hundred and sixty-seven patients met eligibility criteria (M=21.5 years old, s.d.=4.8) and returned for follow-up (M=20.6 months later, s.d.=7.8). Two-hundred and thirty participants were included in the final analysis, comprising clinically stable patients with major depression (n=71), bipolar disorder (BD; n=61), schizophrenia-spectrum disorders (n=35) and 63 healthy controls. Neuropsychological functioning and self-rated functional disability were examined using mixed-design, repeated-measures analysis, across diagnoses and cognitive clusters, covarying for relevant confounds. Clinical, neuropsychological and functional changes did not differ between diagnoses (all P>0.05). Three reliable neuropsychological subgroups emerged through cluster analysis, characterized by psychomotor slowing, improved sustained attention, and improved verbal memory. Controlling for diagnosis and changes in residual symptoms, clusters with improved neuropsychological functioning observed greater reductions in functional disability than the psychomotor slowing cluster, which instead demonstrated a worsening in disability (P<0.01). Improved sustained attention was independently associated with greater likelihood of follow-up employment (P<0.01). Diagnosis of BD uniquely predicted both follow-up employment and independent living. Neuropsychological course appears to be independently predictive of subjective and objective functional outcomes. Importantly, cognitive phenotypes may reflect distinct pathophysiologies shared across major psychiatric conditions, and be ideal targets for personalized early intervention.

Neurocognitive functioning in the premorbid stage and in the first episode of bipolar disorder: a systematic review

It is well known that patients with bipolar disorder (BD) have cognitive impairments even during periods of euthymia. However, to date it remains unclear the moment when these deficits onset. Therefore, the aim of this study was to review the evidence focusing on the cognitive status of patients with BD in their premorbid stage and in their first episode. An extensive search was conducted through the online databases Pubmed/PsychInfo, covering the period between 1980 and 2014. A total of 23 studies were selected for the review (nine studies explored premorbid stage of people who lately develop BD and 14 examined first-episodes in bipolar patients). There is evidence that general intelligence is not impaired in the premorbid stage. Impairments in verbal memory, attention, and executive functions tend to be present during and after the first episode. Preliminary evidence suggests that these deficits in specific cognitive domains might precede the onset of illness.

Schizotypy--do not worry, it is not all worrisome

A long-standing tradition in personality research in psychology, and nowadays increasingly in psychiatry, is that psychotic and psychotic-like thoughts are considered common experiences in the general population. Given their widespread occurrence, such experiences cannot merely reflect pathological functioning. Moreover, reflecting the multi-dimensionality of schizotypy, some dimensions might be informative for healthy functioning while others less so. Here, we explored these possibilities by reviewing research that links schizotypy to favorable functioning such as subjective wellbeing, cognitive functioning (major focus on creativity), and personality correlates. This research highlights the existence of healthy people with psychotic-like traits who mainly experience positive schizotypy (but also affective features mapping onto bipolar disorder). These individuals seem to benefit from a healthy way to organize their thoughts and experiences, that is, they employ an adaptive cognitive framework to explain and integrate their unusual experiences. We conclude that, instead of focusing only on the pathological, future studies should explore the behavioral, genetic, imaging, and psychopharmacological correlates that define the healthy expression of psychotic-like traits. Such studies would inform on protective or compensatory mechanisms of psychosis-risk and could usefully inform us on the evolutionary advantages of the psychosis dimension.

The influence of cognitive reserve on psychosocial and neuropsychological functioning in bipolar disorder

Cognitive reserve (CR) refers to the hypothesized capacity of an adult brain to cope with brain pathology in order to minimize symptomatology. CR was initially investigated in dementia and acute brain damage, but it is being applied to other neuropsychiatric conditions. The present study aims at examining the fit of this concept to a sample of euthymic bipolar patients compared with healthy controls in order to investigate the role of CR in predicting psychosocial and cognitive outcome in bipolar disorder (BD). The sample included 101 subjects: 52 patients meeting DSM-IV-TR criteria for BD type I or II and 49 healthy controls (HC) matched for age and gender. They were all assessed with a cognitive battery tapping into executive and memory functioning. CR was obtained using three different proxies: education-occupation, leisure activities and premorbid IQ. Psychosocial functioning was evaluated by means of the Functioning Assessment Short Test (FAST). MANCOVAs were performed to determine differences in cognitive and functioning variables. Linear regression analyses were carried out to predict neuropsychological and psychosocial outcomes. Euthymic bipolar patients showed worse neuropsychological performance and psychosocial functioning than HC. The linear regression models revealed that CR was significantly predictive of FAST score (β = -0.47, p < 0.0001), Executive Index (β = 0.62, p < 0.0001) and Visual Memory Index (β = 0.44, p = 0.0004), indicating that CR is a significant predictor of cognitive and psychosocial functioning in euthymic bipolar outpatients. Therefore, CR may contribute to functional outcome in BD and may be applied in research and clinical interventions to prevent cognitive and functional impairment.

The FOCUS trial: cognitive remediation plus standard treatment versus standard treatment for patients at ultra-high risk for psychosis: study protocol for a randomised controlled trial

Background

Cognitive deficits are a distinct feature among people at ultra-high risk (UHR) for psychosis and pose a barrier to functional recovery. Insufficient evidence exists on how to ameliorate these cognitive deficits in patients at UHR for psychosis and hence improve daily living and quality of life. The aim of the trial is to investigate whether cognitive remediation can improve cognitive and psychosocial function in patients at UHR for psychosis.

Methods

The FOCUS trial (Function and Overall Cognition in Ultra-high risk States) is a randomised, parallel group, observer-blinded clinical trial enrolling 126 patients meeting the standardised criteria of being at UHR for psychosis. Patients are recruited from psychiatric in- and outpatient facilities in the Copenhagen catchment area. Patients are randomised to one of the two treatment arms: cognitive remediation plus standard treatment versus standard treatment. The cognitive remediation consists of 24 weekly group-based and manualised sessions targeting neurocognition and social cognition. In addition to the group sessions, the patients will be offered 12 individual sessions aiming at maximising the transfer of the effects of the cognitive training to their everyday lives. Follow-up assessments will be conducted at 6 and 12 months after randomisation. The primary outcome is the composite score on the Brief Assessment of Cognition in Schizophrenia at cessation of treatment after 6 months. Secondary outcomes are social and daily functioning, psychosis-like symptoms, negative symptomatology, and depressive symptomatology as measured with the Personal and Social Performance Scale, Brief Psychiatric Rating Scale-Expanded Version, Scale for the Assessment of Negative Symptoms, and the Montgomery-Åsberg Depression Rating Scale.

Discussion

This is the first trial to evaluate the effects of neurocognitive and social cognitive remediation in UHR patients. The FOCUS trial results will provide evidence on the effect of targeted and comprehensive cognitive rehabilitation on cognition, daily living, and symptomatology as well as long-term outcome in preventing transition to psychosis in UHR patients.

Trial registration

ClinicalTrials.gov NCT 02098408. Date of registration 18 March 2014.

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.

Cognitive dysfunction in bipolar disorder and schizophrenia: a systematic review of meta-analyses

Cognitive impairment is a core feature of schizophrenia (SZ) and bipolar disorder (BD). A neurocognitive profile characterized by widespread cognitive deficits across multiple domains in the context of substantial intellectual impairment, which appears to antedate illness onset, is a replicated finding in SZ. There is no specific neuropsychological signature that can facilitate the diagnostic differentiation of SZ and BD, notwithstanding, neuropsychological deficits appear more severe in SZ. The literature in this field has provided contradictory results due to methodological differences across studies. Meta-analytic techniques may offer an opportunity to synthesize findings and to control for potential sources of heterogeneity. Here, we performed a systematic review of meta-analyses of neuropsychological findings in SZ and BD. While there is no conclusive evidence for progressive cognitive deterioration in either SZ or BD, some findings point to more severe cognitive deficits in patients with early illness onset across both disorders. A compromised pattern of cognitive functioning in individuals at familiar and/or clinical risk to psychosis as well as in first-degree relatives of BD patients suggests that early neurodevelopmental factors may play a role in the emergence of cognitive deficits in both disorders. Premorbid intellectual impairment in SZ and at least in a subgroup of patients with BD may be related to a shared genetically determined influence on neurodevelopment.

Self-perceived cognitive functioning and its relationship with objective performance in first-episode schizophrenia: the Subjective Cognitive Impairment Scale

BACKGROUND

Self-perceived cognitive dysfunction is under-recognized in clinical practice and under-studied in schizophrenia, particularly in the early illness stage. Findings on the relationship between subjective and objective cognitive measures were inconsistent. This study aimed to examine psychometric properties of a newly developed scale, Subjective Cognitive Impairment Scale (SCIS) and to investigate the relationship of self-reported ratings with objective test performance in first-episode schizophrenia.

METHODS

One hundred one Chinese patients aged 18 to 64years presenting with first episode schizophrenia-spectrum disorder were studied. A comprehensive set of assessments examining objective cognitive functioning, clinical and treatment characteristic were administered. Internal consistency, factor structure and construct validity of SCIS were evaluated. Correlations of scale score with objective cognitive measures, clinical and treatment variables were examined.

RESULTS

A single-factor underlying the structure of SCIS items was demonstrated by principal components analysis. Cronbach's alpha coefficient for the scale was 0.92. SCIS score was positively correlated with depression and anxiety symptom severity, and duration of untreated psychosis. SCIS score was not associated with other symptom dimensions, insight and chlorpromazine equivalents. No significant correlations were observed between SCIS score and objective cognitive measures with the exception of letter-number span test.

CONCLUSION

Our results provided preliminary evidence in support of reliability and validity of SCIS in evaluating patient's cognitive complaints. A lack of correspondence between subjective and objective cognitive functioning suggested that they may represent two distinct constructs with potentially differential therapeutic implications. Further research is warranted to examine ecological validity and clinical utility of the scale.

Social functioning and age across affective and nonaffective psychoses

Both nonaffective and affective psychoses are associated with deficits in social functioning across the course of the illness. However, it is not clear how social functioning varies among diagnostic groups as a function of age. The current study examined the relationship between social functioning and age in schizophrenia (SZ), schizoaffective disorder (SZA), and psychotic bipolar disorder (PBD). We found that individuals with PBD had the highest functioning, whereas individuals with SZ had the poorest. The functioning of individuals with SZA fell in between those of other groups. We also found that older ages were associated with poorer functioning. Although there was not a significant diagnostic group by age interaction, visual inspection of our data suggests a subtly steeper trajectory of decline in PBD. Overall, these results indicate that early interventions targeting social functioning may benefit individuals with either non-affective or affective psychoses to slow a projected decline.

Altered cortical expression of GABA-related genes in schizophrenia: illness progression vs developmental disturbance

BACKGROUND

Schizophrenia is a neurodevelopmental disorder with altered expression of GABA-related genes in the prefrontal cortex (PFC). However, whether these gene expression abnormalities reflect disturbances in postnatal developmental processes before clinical onset or arise as a consequence of clinical illness remains unclear.

METHODS

Expression levels for 7 GABA-related transcripts (vesicular GABA transporter [vGAT], GABA membrane transporter [GAT1], GABAA receptor subunit α1 [GABRA1] [novel in human and monkey cohorts], glutamic acid decarboxylase 67 [GAD67], parvalbumin, calretinin, and somatostatin [previously reported in human cohort, but not in monkey cohort]) were quantified in the PFC from 42 matched pairs of schizophrenia and comparison subjects and from 49 rhesus monkeys ranging in age from 1 week postnatal to adulthood.

RESULTS

Levels of vGAT and GABRA1, but not of GAT1, messenger RNAs (mRNAs) were lower in the PFC of the schizophrenia subjects. As previously reported, levels of GAD67, parvalbumin, and somatostatin, but not of calretinin, mRNAs were also lower in these subjects. Neither illness duration nor age accounted for the levels of the transcripts with altered expression in schizophrenia. In monkey PFC, developmental changes in expression levels of many of these transcripts were in the opposite direction of the changes observed in schizophrenia. For example, mRNA levels for vGAT, GABRA1, GAD67, and parvalbumin all increased with age.

CONCLUSIONS

Together with published reports, these findings support the interpretation that the altered expression of GABA-related transcripts in schizophrenia reflects a blunting of normal postnatal development changes, but they cannot exclude a decline during the early stages of clinical illness.

Neuropsychological profile and treatment-related features among patients with comorbidity between schizophrenia spectrum disorder and obsessive–compulsive disorder: is there evidence for a “schizo-obsessive” subtype?

Epidemiological studies have found that obsessive–compulsive disorder (OCD) is estimated to occur in 12% of patients with schizophrenia. Whether this “schizo-obsessive” subgroup may be posited as a clinical entity with a distinct neuropsychological profile and treatment-related features remains unclear. A sample of 30 patients who met DSM-IV criteria for both schizophrenia/schizoaffective disorder and OCD was compared with 30 OCD subjects and with 37 patients with schizophrenia/schizoaffective disorder. Neuropsychological domains were measured by the Wechsler Adult Intelligence Scale - Third Edition (WAIS-III), the Trail Making Test (TMT), and the verbal fluency test (FAS). Treatment-related variables were assessed with the Clinical Global Improvement scale (CGI), the Drug Attitude Inventory (DAI), and dosage/type of antipsychotic medications. One-way analysis of variance revealed statistically significant differences among the three groups in “working memory,” “block design,” “semantic fluency,” TMT-A, and TMT-B. However, the Bonferroni correction showed no statistical differences between both psychotic groups. In addition, there were no significant differences among the three groups in the CGI and DAI, although “schizo-obsessive” patients tended to display slightly higher scores on these variables than the other groups. Overall, these findings do not support the hypothesis that comorbidity between schizophrenia spectrum disorders and OCD may reflect a distinct clinical entity. However, further research with larger sample sizes and a more comprehensive clinical assessment are needed. Our findings also underscore the fact that divergences among assessment instruments, as well as confounding variables, may influence results on neuropsychological domains.

Cognitive changes in patients with acute phase psychosis--effects of illicit drug use

Illicit drug use may influence cognition in non-affective psychosis. Previous studies have shown better cognition in psychosis with illicit drug use as compared to psychosis only. Possibly, illicit drug using patients have more transient drug-related cognitive deficits. Thus, the aim of the present study was to examine cognitive change the first weeks after admission to a psychiatric emergency ward, expecting more cognitive improvement at follow-up in the illicit drug group as compared to psychosis only. Patients with acute non-affective psychosis with (26%) and without illicit drug use were examined at baseline (n=123) and follow-up (n=67), with alternative forms of the Repeatable Battery for the Assessment of Neuropsychological Status. Latent Growth Curve models, controlling for cognition at baseline and age differences between the groups, were used to analyze cognitive change. The illicit drug using patients showed the largest improvement in cognition, especially among the youngest patients. Younger patients with non-affective psychosis and illicit drug use showed more cognitive improvement the first weeks after acute psychosis as compared to psychosis only. This suggests that the illicit drug users constitute a sub-group with less stable cognitive deficits and less cognitive vulnerability.

Age at onset, course of illness and response to psychotherapy in bipolar disorder: results from the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD)

BACKGROUND

The course of bipolar disorder progressively worsens in some patients. Although responses to pharmacotherapy appear to diminish with greater chronicity, less is known about whether patients' prior courses of illness are related to responses to psychotherapy.

METHOD

Embedded in the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) was a randomized controlled trial of psychotherapy for bipolar depression comparing the efficacy of intensive psychotherapy with collaborative care (a three-session psycho-educational intervention). We assessed whether the number of previous mood episodes, age of illness onset, and illness duration predicted or moderated the likelihood of recovery and time until recovery from a depressive episode in patients in the two treatments.

RESULTS

Independently of treatment condition, participants with one to nine prior depressive episodes were more likely to recover and had faster time to recovery than those with 20 or more prior depressive episodes. Participants with fewer than 20 prior manic episodes had faster time to recovery than those with 20 or more episodes. Longer illness duration predicted a longer time to recovery. Participants were more likely to recover in intensive psychotherapy than collaborative care if they had 10-20 prior episodes of depression [number needed to treat (NNT) = 2.0], but equally likely to respond to psychotherapy and collaborative care if they had one to nine (NNT = 32.0) or >20 (NNT = 9.0) depressive episodes.

CONCLUSIONS

Number of previous mood episodes and illness duration are associated with the likelihood and speed of recovery among bipolar patients receiving psychosocial treatments for depression.

The Cannabis Pathway to Non-Affective Psychosis may Reflect Less Neurobiological Vulnerability

There is a high prevalence of cannabis use reported in non-affective psychosis. Early prospective longitudinal studies conclude that cannabis use is a risk factor for psychosis, and neurochemical studies on cannabis have suggested potential mechanisms for this effect. Recent advances in the field of neuroscience and genetics may have important implications for our understanding of this relationship. Importantly, we need to better understand the vulnerability × cannabis interaction to shed light on the mediators of cannabis as a risk factor for psychosis. Thus, the present study reviews recent literature on several variables relevant for understanding the relationship between cannabis and psychosis, including age of onset, cognition, brain functioning, family history, genetics, and neurological soft signs (NSS) in non-affective psychosis. Compared with non-using non-affective psychosis, the present review shows that there seem to be fewer stable cognitive deficits in patients with cannabis use and psychosis, in addition to fewer NSS and possibly more normalized brain functioning, indicating less neurobiological vulnerability for psychosis. There are, however, some familiar and genetic vulnerabilities present in the cannabis psychosis group, which may influence the cannabis pathway to psychosis by increasing sensitivity to cannabis. Furthermore, an earlier age of onset suggests a different pathway to psychosis in the cannabis-using patients. Two alternative vulnerability models are presented to integrate these seemingly paradoxical findings.

A stratified model for psychosis prediction in clinical practice

OBJECTIVE

Impaired cognition is an important dimension in psychosis and its at-risk states. Research on the value of impaired cognition for psychosis prediction in at-risk samples, however, mainly relies on study-specific sample means of neurocognitive tests, which unlike widely available general test norms are difficult to translate into clinical practice. The aim of this study was to explore the combined predictive value of at-risk criteria and neurocognitive deficits according to test norms with a risk stratification approach.

METHOD

Potential predictors of psychosis (neurocognitive deficits and at-risk criteria) over 24 months were investigated in 97 at-risk patients.

RESULTS

The final prediction model included (1) at-risk criteria (attenuated psychotic symptoms plus subjective cognitive disturbances) and (2) a processing speed deficit (digit symbol test). The model was stratified into 4 risk classes with hazard rates between 0.0 (both predictors absent) and 1.29 (both predictors present).

CONCLUSIONS

The combination of a processing speed deficit and at-risk criteria provides an optimized stratified risk assessment. Based on neurocognitive test norms, the validity of our proposed 3 risk classes could easily be examined in independent at-risk samples and, pending positive validation results, our approach could easily be applied in clinical practice in the future.

Cognitive impairments in psychotic disorders: common mechanisms and measurement

Decades of research have provided robust evidence of cognitive impairments in psychotic disorders. Individuals with schizophrenia appear to be impaired on the majority of neuropsychological tasks, leading some researchers to argue for a "generalized deficit", in which the multitude of cognitive impairments are the result of a common neurobiological source. One such common mechanism may be an inability to actively represent goal information in working memory as a means to guide behavior, with the associated neurobiological impairment being a disturbance in the function of the dorsolateral prefrontal cortex. Here, we provide a discussion of the evidence for such impairment in schizophrenia, and how it manifests in domains typically referred to as cognitive control, working memory and episodic memory. We also briefly discuss cognitive impairment in affective psychoses, reporting that the degree of impairment is worse in schizophrenia than in bipolar disorder and psychotic major depression, but the profile of impairment is similar, possibly reflecting common mechanisms at the neural level. Given the recent release of the DSM-5, we end with a brief discussion on assessing cognition in the context of diagnosis and treatment planning in psychotic disorders.

A preliminary validity study of the cambridge neuropsychological test automated battery for the assessment of executive function in schizophrenia and bipolar disorder

OBJECTIVE

Although the executive function subtests of the Cambridge Neuropsychological Test Automated Battery (CANTAB) have been used to assess cognitive function in diverse psychiatric illnesses, few studies have verified the validity of this battery for Korean psychiatric patients. Therefore, this preliminary study evaluated the construct and concurrent validity of the executive function subtests of the CANTAB for Korean psychiatric patients by comparing it with subtests of the Computerized Neuropsychological Test (CNT).

METHODS

Three subtests of the CANTAB and three subtests of the CNT were administered to 36 patients diagnosed with either schizophrenia or bipolar disorder. Subtests of the CANTAB included the Intra/Extra-Dimensional Set Shift (IED), Stockings of Cambridge (SOC), and Spatial Working Memory (SWM). Differences between groups on each subtest as well as correlations between the subtests of the CANTAB and the CNT were assessed.

RESULTS

The schizophrenia group performed significantly more poorly on the IED and the Wisconsin Card Sorting Test (WCST) compared with the bipolar disorder group. Additionally, correlation analyses revealed a significant correlation between the IED and the WCST; a positive correlation between the SOC and the Trail Making Test, Part B and the Stroop test; and a significant correlation between the SWM and the Stroop test.

CONCLUSION

This study verified the construct and concurrent validity of the executive function subtests of the CANTAB for Korean psychiatric patients and suggests that the subtests of this battery would be useful and appropriate for assessing deficits in executive function in Korean clinical settings.

Disease and drug effects on internally-generated and externally-elicited responses in first episode schizophrenia and psychotic bipolar disorder

Neurocognitive deficits are associated with most psychotic disorders, but may differ across diagnosis and by treatment status. This ambiguity is partly addressed in longitudinal pre/post treatment studies with first episode patients. Antipsychotic-naïve first-episode schizophrenia patients have shown intact performance on a predictive saccade task that assesses simple motor learning, spatial abilities, and response planning. After antipsychotic treatment, however, schizophrenia patients performing this task show a selective impairment in the accuracy of anticipatory responses, generated from learned internal representations of the task stimulus. This finding is in line with other observations of antipsychotic medication effects on frontostriatal systems, particularly dorsolateral prefrontal cortex. We sought to replicate this provocative finding with an independent sample of antipsychotic-naïve first-episode schizophrenia patients and extend it by including a group of patients with first episode bipolar disorder with psychosis (BDP). Matched healthy controls were also studied in parallel. Schizophrenia patients demonstrated intact performance pretreatment followed by impairment post-treatment for accuracy of anticipatory responses, and worse accuracy was associated with higher antipsychotic dose. BDP patients displayed saccade accuracy deficits before and after treatment and had no correlation of performance and antipsychotic dose. The findings suggest different neural alterations early in the course of each psychotic disorder, and different vulnerabilities to antipsychotic treatment effects between schizophrenia and BDP.

A meta-analysis of neuropsychological functioning in first-episode bipolar disorders

Broad neuropsychological deficits have been consistently demonstrated in well-established bipolar disorder. The aim of the current study was to systematically review neuropsychological studies in first-episode bipolar disorders to determine the breadth, extent and predictors of cognitive dysfunction at this early stage of illness through meta-analytic procedures. Electronic databases were searched for studies published between January 1980 and December 2013. Twelve studies met eligibility criteria (N = 341, mean age = 28.2 years), and pooled effect sizes (ES) were calculated across eight cognitive domains. Moderator analyses were conducted to identify predictors of between-study heterogeneity. Controlling for known confounds, medium to large deficits (ES ≥ 0.5) in psychomotor speed, attention and working memory, and cognitive flexibility were identified, whereas smaller deficits (ES 0.20-0.49) were found in the domains of verbal learning and memory, attentional switching, and verbal fluency. A medium to large deficit in response inhibition was only detected in non-euthymic cases. Visual learning and memory functioning was not significantly worse in cases compared with controls. Overall, first-episode bipolar disorders are associated with widespread cognitive dysfunction. Since euthymia was not associated with superior cognitive performance in most domains, these results indicate that even in the earliest stages of disease, cognitive deficits are not mood-state dependent. The current findings have important implications for whether cognitive impairments represent neurodevelopmental or neurodegenerative processes. Future studies need to more clearly characterise the presence of psychotic features, and the nature and number of previous mood episodes.

A longitudinal study on the relationship between duration of untreated psychosis and executive function in early-onset first-episode psychosis

BACKGROUND

The relationship between duration of untreated psychosis (DUP) and executive function (EF) in patients with first-episode psychosis (FEP) is controversial. We aim to assess the influence of DUP on changes in EF over a 2-year period in subjects with early-onset FEP (first psychotic symptom before age 18) and less than 6 months of positive symptoms.

METHODS

A total of 66 subjects were included in the study (19 females [28.8%], mean age 16.2 ± 1.6 years). The influence of DUP on changes in EF over the 2-year follow-up (expressed as a composite score of 5 cognitive abilities: attention, working memory, cognitive flexibility, response inhibition, and problem solving) was estimated using a multivariate linear regression model after removing the effect of intelligence quotient and controlling for age, gender, diagnosis, premorbid adjustment, severity of positive and negative symptoms at baseline, global functioning at baseline, and mean daily antipsychotic dosage during follow-up.

RESULTS

Mean DUP was 65.0 ± 6.9 days (95% confidence interval [CI], 51.2, 78.8). Median DUP was 47.5 days (range 2-180 days). Negative symptoms at baseline was the only variable significantly associated with EF at baseline (10.9% of explained variance [e.v. 10.9%], p=0.007). Only shorter DUP (e.v. 8.7%, p=0.013) and greater severity of baseline negative symptoms (e.v. 10.0%, p=0.008) were significantly associated with greater improvement in EF.

CONCLUSIONS

In early-onset FEP, shorter DUP was associated with greater improvement in EF over a 2-year follow-up period.

Early intermodal integration in offspring of parents with psychosis

Identifying early developmental indicators of risk for schizophrenia is important for prediction and possibly illness prevention. Disturbed intermodality has been proposed as one important neurodevelopmental risk for schizophrenia. Early intermodal integration (EII) is the infant's ability to link motility and perception and to relate perception across modalities. We hypothesized that infants of parents with schizophrenia would have more EII abnormalities than infants of healthy parents and that infants of parents with affective psychosis would be intermediate in severity. The New England Family Study high-risk sample, ascertained from community populations, was utilized. Eight-month-old infants of parents with schizophrenia (n = 58), affective psychoses (n = 128), and healthy controls (n = 174) were prospectively assessed. Diagnoses of parents were determined 30 years later blind to offspring data. EII measures were grouped into 3 domains characterizing different aspects of infant development: (1) one's own body, (2) objects, and (3) social interactions. Results demonstrated that body- and object-related EII abnormalities were significantly increased for infants of parents with schizophrenia compared with control infants and not significantly increased for infants of parents with affective psychoses. EII abnormalities in relation to social interactions were significantly increased in infants of parents with schizophrenia and affective psychoses. Thus, body- and object-related EII abnormalities were most severe in infants of parents with schizophrenia, supporting the importance of intermodality dysfunction as an early indicator of the vulnerability to schizophrenia. Future research should evaluate how this dysfunction evolves with development and its associations with other psychopathological and neurodevelopmental deficits in youth at risk for psychosis.

The course of neuropsychological impairment and brain structure abnormalities in psychotic disorders

Neuropsychological impairment and abnormalities in brain structure are commonly observed in psychotic disorders, including schizophrenia and bipolar disorder. Shared deficits in neuropsychological functioning and abnormalities in brain structure suggest overlapping neuropathology between schizophrenia and bipolar disorder which has important implications for psychiatric nosology, treatment, and our understanding of the etiology of psychotic illnesses. However, the emergence and trajectory of brain dysfunction in psychotic disorders is less well understood. Differences in the course and progression of neuropsychological impairment and brain abnormalities among psychotic disorders may point to unique neuropathological processes. This article reviews the course of neuropsychological impairment and brain structure abnormalities in schizophrenia and bipolar disorder.

Selective effect of neurocognition on different theory of mind domains in first-episode psychosis

The aim of this study was to investigate the influence of neurocognition on affective and cognitive theory of mind (ToM) tasks in early phases of psychosis. In a cross-sectional study of 60 first-episode schizophrenia/schizoaffective disorder patients, the implication of neurocognition in first- and second-order ToM stories, Hinting Task, and Reading the Mind in the Eyes Test (RMET) was analyzed. Regression models were used, controlling for clinical symptoms and antipsychotic dose. Spatial span backward (odds ratio [OR], 0.34; p = 0.01) and intrusions in the Rey Auditory Verbal Learning Test (OR, 4.86; p = 0.04) were the best factors to predict second-order ToM failure. Trail Making Test B (B = 0.01; p = 0.04) and negative symptoms (B = 0.09; p = 0.01) predicted Hinting task performance while Block design (B = 0.1; p = 0.04) was related to RMET outcome. Executive functions and clinical symptoms were related to ToM performance in first-episode schizophrenia patients, although different patterns of relationship were observed in each ToM task.

Cognitive functioning in first-episode schizophrenia: MATRICS Consensus Cognitive Battery (MCCB) Profile of Impairment

BACKGROUND

Although many studies have assessed cognitive functioning in first-episode schizophrenia (FESz), the pattern and severity of impairment across cognitive domains remain unclear. Moreover, few studies have directly compared the pattern of cognitive performance between FESz and chronic schizophrenia (CSz). In this study we examined the cognitive impairment profile in FESz using a standardized neurocognitive battery (MATRICS Consensus Cognitive Battery; MCCB).

METHODS

MCCB data were compared from 105 FESz patients, 176 CSz patients and 300 non-psychiatric (NP) participants. Mixed model analysis evaluated group differences in MCCB profiles and relative strengths and weaknesses in the MCCB profiles of patients. Clinical implications of MCCB performance were also examined; we compared the proportion of participants from each group who exhibited clinically-significant global cognitive impairment based on the MCCB Overall Composite score.

RESULTS

FESz and CSz showed impaired performance across all MCCB domains relative to NP. With the exception of relative preservation of working memory and social cognition in FESz, the MCCB domain scores were similar in FESz and CSz. The distribution of impairment on the Overall Composite score did not significantly differ between FESz and CSz; compared to NP, both patient groups were overrepresented in moderate and severe impairment categories.

CONCLUSION

The pattern, magnitude, and distribution of severity of impairment in FESz were similar to that observed in CSz. However, early in the illness, there may be relative sparing of working memory and social cognition.

Advancing biomarker research: utilizing 'Big Data' approaches for the characterization and prevention of bipolar disorder

OBJECTIVE

To provide a strategic framework for the prevention of bipolar disorder (BD) that incorporates a 'Big Data' approach to risk assessment for BD.

METHODS

Computerized databases (e.g., Pubmed, PsychInfo, and MedlinePlus) were used to access English-language articles published between 1966 and 2012 with the search terms bipolar disorder, prodrome, 'Big Data', and biomarkers cross-referenced with genomics/genetics, transcriptomics, proteomics, metabolomics, inflammation, oxidative stress, neurotrophic factors, cytokines, cognition, neurocognition, and neuroimaging. Papers were selected from the initial search if the primary outcome(s) of interest was (were) categorized in any of the following domains: (i) 'omics' (e.g., genomics), (ii) molecular, (iii) neuroimaging, and (iv) neurocognitive.

RESULTS

The current strategic approach to identifying individuals at risk for BD, with an emphasis on phenotypic information and family history, has insufficient predictive validity and is clinically inadequate. The heterogeneous clinical presentation of BD, as well as its pathoetiological complexity, suggests that it is unlikely that a single biomarker (or an exclusive biomarker approach) will sufficiently augment currently inadequate phenotypic-centric prediction models. We propose a 'Big Data'- bioinformatics approach that integrates vast and complex phenotypic, anamnestic, behavioral, family, and personal 'omics' profiling. Bioinformatic processing approaches, utilizing cloud- and grid-enabled computing, are now capable of analyzing data on the order of tera-, peta-, and exabytes, providing hitherto unheard of opportunities to fundamentally revolutionize how psychiatric disorders are predicted, prevented, and treated. High-throughput networks dedicated to research on, and the treatment of, BD, integrating both adult and younger populations, will be essential to sufficiently enroll adequate samples of individuals across the neurodevelopmental trajectory in studies to enable the characterization and prevention of this heterogeneous disorder.

CONCLUSIONS

Advances in bioinformatics using a 'Big Data' approach provide an opportunity for novel insights regarding the pathoetiology of BD. The coordinated integration of research centers, inclusive of mixed-age populations, is a promising strategic direction for advancing this line of neuropsychiatric research.

Meta-analysis of cognitive deficits in ultra-high risk to psychosis and first-episode psychosis: do the cognitive deficits progress over, or after, the onset of psychosis?

Cognitive dysfunction is a well-established feature of schizophrenia, and there is evidence suggesting that cognitive deficits are secondary to abnormal neurodevelopment leading to problems in acquiring such abilities. However, it is not clear whether there is also a decline in cognitive performance over, or after, the onset of psychosis. Our objective was to quantitatively examine the longitudinal changes in cognitive function in patients who presented with first-episode psychosis (FEP), ultra-high risk (UHR) for psychosis, and controls. Electronic databases were searched for the studies published between January 1987 and February 2013. All studies reporting longitudinal cognitive data in FEP and UHR subjects were retrieved. We conducted meta-analyses of 25 studies including 905 patients with FEP, 560 patients at UHR, and 405 healthy controls. The cognitive performances of FEP, UHR, and healthy controls all significantly improved over time. There was no publication bias, and distributions of effect sizes were very homogenous. In FEP, the degree of improvement in verbal working memory and executive functions was significantly associated with reduction in negative symptoms. There was no evidence of cognitive decline in patients with UHR and FEP. In contrast, the cognitive performances of both groups improved at follow-up. These findings suggest that cognitive deficits are already established before the prodromal phases of psychosis. These data support the neurodevelopmental model rather than neurodegenerative and related staging models of schizophrenia.

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.

Differential effects of common variants in SCN2A on general cognitive ability, brain physiology, and messenger RNA expression in schizophrenia cases and control individuals

IMPORTANCE

One approach to understanding the genetic complexity of schizophrenia is to study associated behavioral and biological phenotypes that may be more directly linked to genetic variation.

OBJECTIVE

To identify single-nucleotide polymorphisms associated with general cognitive ability (g) in people with schizophrenia and control individuals.

DESIGN, SETTING, AND PARTICIPANTS

Genomewide association study, followed by analyses in unaffected siblings and independent schizophrenia samples, functional magnetic resonance imaging studies of brain physiology in vivo, and RNA sequencing in postmortem brain samples. The discovery cohort and unaffected siblings were participants in the National Institute of Mental Health Clinical Brain Disorders Branch schizophrenia genetics studies. Additional schizophrenia cohorts were from psychiatric treatment settings in the United States, Japan, and Germany. The discovery cohort comprised 339 with schizophrenia and 363 community control participants. Follow-up analyses studied 147 unaffected siblings of the schizophrenia cases and independent schizophrenia samples including a total of an additional 668 participants. Imaging analyses included 87 schizophrenia cases and 397 control individuals. Brain tissue samples were available for 64 cases and 61 control individuals.

MAIN OUTCOMES AND MEASURES

We studied genomewide association with g, by group, in the discovery cohort. We used selected genotypes to test specific associations in unaffected siblings and independent schizophrenia samples. Imaging analyses focused on activation in the prefrontal cortex during working memory. Brain tissue studies yielded messenger RNA expression levels for RefSeq transcripts.

RESULTS

The schizophrenia discovery cohort showed genomewide-significant association of g with polymorphisms in sodium channel gene SCN2A, accounting for 10.4% of g variance (rs10174400, P = 9.27 × 10(-10)). Control individuals showed a trend for g/genotype association with reversed allelic directionality. The genotype-by-group interaction was also genomewide significant (P = 1.75 × 10(-9)). Siblings showed a genotype association with g parallel to the schizophrenia group and the same interaction pattern. Parallel, but weaker, associations with cognition were found in independent schizophrenia samples. Imaging analyses showed a similar pattern of genotype associations by group and genotype-by-group interaction. Sequencing of RNA in brain revealed reduced expression in 2 of 3 SCN2A alternative transcripts in the patient group, with genotype-by-group interaction, that again paralleled the cognition effects.

CONCLUSIONS AND RELEVANCE

The findings implicate SCN2A and sodium channel biology in cognitive impairment in schizophrenia cases and unaffected relatives and may facilitate development of cognition-enhancing treatments.

Neuropsychological Deficits in the Prodromal Phase and Course of an Early-Onset Schizophrenia

Objectives: Although clear advances have been achieved in the study of early-onset schizophrenia (EOS), little is known to date about premorbid and prodromal neuropsychological functioning in EOS. Method: Here, we report on a case of an adolescent male with EOS who underwent neuropsychological testing before and after illness onset. Results: Marked cognitive deficits in the domains of attention, set-shifting, and verbal memory were present both pre-onset and during the course of schizophrenia, though only deficits in verbal memory persisted after illness-onset and antipsychotic treatment. Conclusion: The findings of this case study suggest that impairments in the verbal memory domain are particularly prominent symptoms of cognitive impairment in prodromal EOS and persist in the course of the disorder, which further demonstrates the difficult clinical situation of adequate schooling opportunities for adolescent patients with EOS.

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.

Neuropathological and neuromorphometric abnormalities in bipolar disorder: view from the medial prefrontal cortical network

The question of whether BD is primarily a developmental disorder or a progressive, neurodegenerative disorder remains unresolved. Here, we review the morphometric postmortem and neuroimaging literature relevant to the neuropathology of bipolar disorder (BD). We focus on the medial prefrontal cortex (mPFC) network, a key system in the regulation of emotional, behavioral, endocrine, and innate immunological responses to stress. We draw four main conclusions: the mPFC is characterized by (1) a decrease in volume, (2) reductions in neuronal size, and/or changes in neuronal density, (3) reductions in glial cell density, and (4) changes in gene expression. These data suggest the presence of dendritic atrophy of neurons and the loss of oligodendroglial cells in BD, although some data additionally suggest a reduction in the cell counts of specific subpopulations of GABAergic interneurons. Based on the weight of the postmortem and neuroimaging literature discussed herein, we favor a complex hypothesis that BD primarily constitutes a developmental disorder, but that additional, progressive, histopathological processes also are associated with recurrent or chronic illness. Conceivably BD may be best conceptualized as a progressive neurodevelopmental disorder.

Autobiographical memory and its association with neuropsychological function in bipolar disorder

OBJECTIVE

The aim of this study was to investigate the overgeneralization of autobiographical memory (AM) in bipolar disorder (BD) and assess its association with multiple cognitive domains.

METHOD

Twenty-eight clinically stable bipolar I patients and an equal number of age- and gender-matched healthy controls (HC) were included. All participants were examined using the autobiographical memory test (AMT) and the neuropsychological battery including the general intelligence, attention, verbal memory, verbal fluency, visual memory, and executive functions domain. Demographic, clinical, and test variables were compared between BD and HC groups. Correlation analyses of AMT scores with cognitive functions were performed within each group, controlling for demographic and clinical variables.

RESULTS

Total and negative scores of AMT were significantly lower in BD patients compared to HC individuals. AMT scores were significantly correlated with WAIS similarities, WCST perseverative errors, and WCST categories completed in BD, whereas AMT scores were correlated with verbal memory and verbal fluency in HC.

CONCLUSION

Our findings suggest that overgeneral AM is a characteristic of BD and is related to executive function. Future studies should investigate the benefit of additional treatment focusing on overgeneral AM in BD.

A systematic review of cognitive function in first-episode psychosis, including a discussion on childhood trauma, stress, and inflammation

OBJECTIVE

To carry out a systematic review of the literature addressing cognitive functions in first-episode psychosis (FEP), divided into domains. Although this is not a full "cognitive-genetics-in-schizophrenia review," we will also include putative ideas of mechanism(s) behind these impairments, focusing on how early stress, and genetic vulnerability may moderate cognitive function in psychosis.

METHOD

Relevant studies were identified via computer literature searches for research published up to and including January 2013, only case-control studies were included for the neurocognitive meta-analysis.

RESULTS

Patients with FEP present global cognitive impairment compared to healthy controls. The largest effect size was observed for verbal memory (Cohen's d effect size = 2.10), followed by executive function (effect size = 1.86), and general IQ (effect size = 1.71). However, effect sizes varied between studies.

CONCLUSION

Cognitive impairment across domains, up to severe level based on Cohen's effect size, is present already in FEP studies. However, differences in levels of impairment are observed between studies, as well as within domains, indicating that further consolidation of cognitive impairment over the course of illness may be present. Cognitive abnormalities may be linked to a neurodevelopmental model including increased sensitivity to the negative effect of stress, as well as genetic vulnerability. More research on this field is needed.

The myth of schizophrenia as a progressive brain disease

Schizophrenia has historically been considered to be a deteriorating disease, a view reinforced by recent MRI findings of progressive brain tissue loss over the early years of illness. On the other hand, the notion that recovery from schizophrenia is possible is increasingly embraced by consumer and family groups. This review critically examines the evidence from longitudinal studies of (1) clinical outcomes, (2) MRI brain volumes, and (3) cognitive functioning. First, the evidence shows that although approximately 25% of people with schizophrenia have a poor long-term outcome, few of these show the incremental loss of function that is characteristic of neurodegenerative illnesses. Second, MRI studies demonstrate subtle developmental abnormalities at first onset of psychosis and then further decreases in brain tissue volumes; however, these latter decreases are explicable by the effects of antipsychotic medication, substance abuse, and other secondary factors. Third, while patients do show cognitive deficits compared with controls, cognitive functioning does not appear to deteriorate over time. The majority of people with schizophrenia have the potential to achieve long-term remission and functional recovery. The fact that some experience deterioration in functioning over time may reflect poor access, or adherence, to treatment, the effects of concurrent conditions, and social and financial impoverishment. Mental health professionals need to join with patients and their families in understanding that schizophrenia is not a malignant disease that inevitably deteriorates over time but rather one from which most people can achieve a substantial degree of recovery.

Resting state functional connectivity of five neural networks in bipolar disorder and schizophrenia

BACKGROUND

Bipolar disorder (BPD) and schizophrenia (SCZ) share clinical characteristics and genetic contributions. Functional dysconnectivity across various brain networks has been reported to contribute to the pathophysiology of both SCZ and BPD. However, research examining resting-state neural network dysfunction across multiple networks to understand the relationship between these two disorders is lacking.

METHODS

We conducted a resting-state functional connectivity fMRI study of 35 BPD and 25 SCZ patients, and 33 controls. Using previously defined regions-of-interest, we computed the mean connectivity within and between five neural networks: default mode (DM), fronto-parietal (FP), cingulo-opercular (CO), cerebellar (CER), and salience (SAL). Repeated measures ANOVAs were used to compare groups, adjusting false discovery rate to control for multiple comparisons. The relationship of connectivity with the SANS/SAPS, vocabulary and matrix reasoning was investigated using hierarchical linear regression analyses.

RESULTS

Decreased within-network connectivity was only found for the CO network in BPD. Across groups, connectivity was decreased between CO-CER (p<0.001), to a larger degree in SCZ than in BPD. In SCZ, there was also decreased connectivity in CO-SAL, FP-CO, and FP-CER, while BPD showed decreased CER-SAL connectivity. Disorganization symptoms were predicted by connectivity between CO-CER and CER-SAL.

DISCUSSION

Our findings indicate dysfunction in the connections between networks involved in cognitive and emotional processing in the pathophysiology of BPD and SCZ. Both similarities and differences in connectivity were observed across disorders. Further studies are required to investigate relationships of neural networks to more diverse clinical and cognitive domains underlying psychiatric disorders.

Neurocognitive functioning in schizophrenia and during the early phases of psychosis: targeting cognitive remediation interventions

Recent interest in the early course of schizophrenia accentuated altered cognition prior to the onset. Ultrahigh risk (UHR) individuals with attenuated positive symptoms and transient psychotic episodes demonstrate neurocognitive deficits across multiple domains such as memory, executive functioning, and processing speed which are consistent with similar disturbances identified in patients with a first episode of schizophrenia. Cognitive remediation (CR) approaches representing a broad set of activities are aimed to restore or improve cognitive functioning. CR proved to be effective in modulating the cognitive dysfunction in schizophrenia but is rarely used in ultrahigh risk individuals. From the clinical prospective, a better understanding of cognitive functioning in at-risk states is essential for the development of optimal early intervention models. In the review, we highlight the intervention targets, notably the specific cognitive deficits in at risk individuals which preceed the transition to psychosis and emphasize the need of the additional studies using CR approaches in UHR group aiming to enhance cognition and therefore mediate functional improvement.

Relationship between frontostriatal morphology and executive function deficits in bipolar I disorder following a first manic episode: data from the Systematic Treatment Optimization Program for Early Mania (STOP-EM)

OBJECTIVES

Executive function impairments are a core feature of bipolar I disorder (BD-I), not only present during acute episodes but also persisting following remission of mood symptoms. Despite advances in knowledge regarding the neural basis of executive functions in healthy subjects, research into morphological abnormalities underlying the deficits in BD-I is lacking.

METHODS

Patients with BD-I within three months of sustained remission from their first manic episode (n = 41) underwent neuropsychological testing and a 3T magnetic resonance imaging scan and were compared to healthy subjects matched for age, sex, and premorbid IQ (n = 30). Group dorsolateral prefrontal cortex (DLPFC; Brodmann areas 9 and 46) and caudate volumes were examined and analyzed for relationships with the average score from three computerized tests of executive function: Spatial Working Memory, Stockings of Cambridge, and Intradimensional/Extradimensional Shift.

RESULTS

Right caudate volumes were enlarged in patients (z = 3.57, p < 0.05 corrected). No differences in DLPFC volumes were found. Patients showed large deficits in executive function relative to healthy subjects (d = -0.92, p < 0.001). While in healthy subjects, a larger right (r = +0.39, p < 0.05) and left (r = +0.44, p < 0.05) caudate was associated with better executive function score, in patients, larger right (r = -0.36, p < 0.05) and left (r = -0.34, p < 0.05) volumes correlated with poorer performance.

CONCLUSIONS

Although the etiology of gray matter changes is unknown, volume increases in the right caudate may be an important factor underlying executive function impairments during remission in patients with BD-I.

Visual context processing in bipolar disorder: a comparison with schizophrenia

Anomalous perception has been investigated extensively in schizophrenia, but it is unclear whether these impairments are specific to schizophrenia or extend to other psychotic disorders. Recent studies of visual context processing in schizophrenia (Tibber et al., 2013; Yang et al., 2013) point to circumscribed, task-specific abnormalities. Here we examined visual contextual processing across a comprehensive set of visual tasks in individuals with bipolar disorder and compared their performance with that of our previously published results from schizophrenia and healthy participants tested on those same tasks. We quantified the degree to which the surrounding visual context alters a center stimulus' appearance for brightness, size, contrast, orientation and motion. Across these tasks, healthy participants showed robust contextual effects, as indicated by pronounced misperceptions of the center stimuli. Participants with bipolar disorder showed contextual effects similar in magnitude to those found in healthy participants on all tasks. This result differs from what we found in schizophrenia participants (Yang et al., 2013) who showed weakened contextual modulations of contrast but intact contextual modulations of perceived luminance and size. Yet in schizophrenia participants, the magnitude of the contrast illusion did not correlate with symptom measures. Performance on the contrast task by the bipolar disorder group also could not be distinguished from that of the schizophrenia group, and this may be attributed to the result that bipolar patients who presented with greater manic symptoms showed weaker contrast modulation. Thus, contrast gain control may be modulated by clinical state in bipolar disorder. Stronger motion and orientation context effects correlated with worse clinical symptoms across both patient groups and especially in schizophrenia participants. These results highlight the complexity of visual context processing in schizophrenia and bipolar disorder.

Effect of aripiprazole on cognitive function and hyperprolactinemia in patients with schizophrenia treated with risperidone

Objective

This study aimed to assess the efficacy of aripiprazole for the management of cognitive impairments and hyperprolactinemia in patients with schizophrenia on a stable dose of risperidone.

Methods

Thirty-five subjects stabilized on risperidone (3-6 mg/day) for a minimum of 3 months were enrolled in a double-blind, placebo-controlled phase for 12 weeks and an open-label phase for another 12 weeks. Subjects were randomly assigned to receive 10 mg/day aripiprazole (n=17) or placebo (n=18). Over the following 12 weeks, the the aripiprazole group received a flexible dose of aripiprazole while tapering risperidone. At baseline, week 12, and week 24, subjects were evaluated using the Positive and Negative Syndrome Scale (PANSS), Extrapyramidal Syndrome Rating Scale (ESRS), and standardized neuropsychological assessments. Serum prolactin levels were checked at baseline, week 1, week 2, and week 24.

Results

The mean change in total PANSS and cognitive function test scores between baseline and endpoint were similar in the aripiprazole and placebo groups. Scores on the ESRS and negative subscale of PANSS differed significantly between groups in both phases of the study (p<0.05), indicating a positive effect of aripiprazole. Compared with placebo, aripiprazole significantly reduced mean baseline serum prolactin levels within 1 week (p=0.015).

Conclusion

Adjunctive treatment with and switching to aripiprazole were not associated with improved cognitive function in patients with schizophrenia receiving risperidone; however, aripiprazole treatment decreased negative symptoms and risperidone-induced motor side effects and lowered serum prolactin levels.

Neuropsychological functioning predicts community outcomes in affective and non-affective psychoses: a 6-month follow-up

INTRODUCTION

Neurocognitive dysfunction is a major symptom feature of schizophrenia and bipolar disorder. A prognostic relationship between cognition and community outcomes is well-documented in schizophrenia and increasingly recognized in bipolar disorder. However, specific associations among neurocognition, diagnosis, state symptomatology, and community functioning are unclear, and few studies have compared these relationships among patients with affective and non-affective psychoses in the same study. We examined neurocognitive, clinical, and community functioning in a cross-diagnostic sample of patients with psychotic disorders over a 6-month follow-up interval.

METHOD

Neurocognitive, clinical and community functioning were assessed in participants with schizophrenia (n=13), schizoaffective disorder (n=17), or bipolar disorder with psychosis (n=18), and healthy controls (n=18) at baseline and 6months later.

RESULTS

Neurocognitive functioning was impaired in all diagnostic groups and, despite reductions in primary symptoms, did not recover on most measures over the follow-up period. Neurocognitive impairment was not associated with diagnosis or clinical improvement. Several neurocognitive scores at baseline (but not diagnosis or clinical baseline or follow-up scores) predicted community functioning at follow-up.

DISCUSSION

In one of the few studies to longitudinally examine neurocognition in association with clinical and outcomes variables in a cross diagnostic sample of psychotic disorders patients, neurocognitive deficits were pronounced across diagnoses and did not recover on most measures despite significant reductions in clinical symptoms. Baseline neurocognitive functioning was the only significant predictor of patients' community functioning six months later. Efforts to recognize and address cognitive deficits, an approach that has shown promise in schizophrenia, should be extended to all patients with psychosis.

Neurocognitive functioning in the prodrome of mania--an exploratory study

BACKGROUND

Cognitive deficits have been well documented in individuals with bipolar disorder (BD) after the first episode of mania. However, little is known about the presence of such deficits prior to the initial manic episode.

METHODS

Participants were recruited from a cohort of 416 young people who were at ultra-high risk (UHR) for psychosis and were followed up between 4 and 13 years later. The current report is of 16 participants who developed BD over a mean follow-up period of 8.2 years (UHR-BD). Baseline demographic, clinical and neurocognitive assessment scores were compared with those of 46 age and gender matched UHR subjects who did not transition to psychosis or BD over the follow-up period (UHR-NT) and 66 healthy comparison subjects.

RESULTS

UHR-BD subjects had lower global functioning at baseline compared with UHR-NT subjects. There were no significant differences between UHR-BD and UHR-NT subjects on baseline demographic and neurocognitive characteristics. UHR-BD subjects had lower test performance than HC on picture completion, Trail-Making Tests and measures of global intelligence.

LIMITATIONS

Small sample size, limited and variable neurocognitive tests utilised and the confounding effects of psychotic symptoms might have impacted on the ability to detect meaningful clinical and neurocognitive differences.

CONCLUSIONS

In this exploratory study, neurocognition in young people who later develop BD is similar to those of subjects who are at a high risk for psychotic disorders, but there may be certain neurocognitive markers that distinguish this group from unaffected and healthy young people.

Redox dysregulation in the pathophysiology of schizophrenia and bipolar disorder: insights from animal models

SIGNIFICANCE

Schizophrenia (SZ) and bipolar disorder (BD) are classified as two distinct diseases. However, accumulating evidence shows that both disorders share genetic, pathological, and epidemiological characteristics. Based on genetic and functional findings, redox dysregulation due to an imbalance between pro-oxidants and antioxidant defense mechanisms has been proposed as a risk factor contributing to their pathophysiology.

RECENT ADVANCES

Altered antioxidant systems and signs of increased oxidative stress are observed in peripheral tissues and brains of SZ and BD patients, including abnormal prefrontal levels of glutathione (GSH), the major cellular redox regulator and antioxidant. Here we review experimental data from rodent models demonstrating that permanent as well as transient GSH deficit results in behavioral, morphological, electrophysiological, and neurochemical alterations analogous to pathologies observed in patients. Mice with GSH deficit display increased stress reactivity, altered social behavior, impaired prepulse inhibition, and exaggerated locomotor responses to psychostimulant injection. These behavioral changes are accompanied by N-methyl-D-aspartate receptor hypofunction, elevated glutamate levels, impairment of parvalbumin GABA interneurons, abnormal neuronal synchronization, altered dopamine neurotransmission, and deficient myelination.

CRITICAL ISSUES

Treatment with the GSH precursor and antioxidant N-acetylcysteine normalizes some of those deficits in mice, but also improves SZ and BD symptoms when given as adjunct to antipsychotic medication.

FUTURE DIRECTIONS

These data demonstrate the usefulness of GSH-deficient rodent models to identify the mechanisms by which a redox imbalance could contribute to the development of SZ and BD pathophysiologies, and to develop novel therapeutic approaches based on antioxidant and redox regulator compounds.