Cognitive functioning in patients with schizophrenia and bipolar disorder: a quantitative review

The impact of familial risk for schizophrenia or bipolar disorder on cognitive control during episodic memory retrieval

Episodic memory impairment is a robust correlate of familial risk for schizophrenia (SZ) and bipolar disorder (BD); still much is unknown about the processes that underlie this deficit and how they may be implicated in BD and SZ. We examined the possibility that (a) episodic memory impairment may arise from abnormalities in the cognitive control of interference between task-relevant and task-irrelevant memories during retrieval; inability to suppress task-irrelevant representations could give rise to intrusions of inappropriate memories and increased rate of forgetting, (b) cognitive control deficits during retrieval may be differentially affected by familial predisposition to SZ or BD. We examined episodic memory in relatives of patients with SZ (SZ-R) (n=15) or BD (BD-R) (n=17) compared to healthy controls (n=23) using the California Verbal Learning Test (CVLT) and the Doors and People Test (DPT). All relatives were free of any psychiatric morbidity and were matched to controls on age, sex, educational achievement and general intellectual ability. During the CVLT, both relatives' groups made significantly more perseverative recall errors than controls. However, intrusion errors were significantly increased in SZ-R only. SZ-R also showed increased rate of forgetting in the DPT while BD-R were comparable to controls. Familial predisposition to SZ, compared to that of BD, was associated with significantly greater impairment in cognitive control processes during episodic memory retrieval with some evidence of specificity for SZ in connection with mechanisms relating to increased forgetting.

Meta-analysis of the association between cognitive abilities and everyday functioning in bipolar disorder

OBJECTIVES

Neurocognitive deficits are common in bipolar disorder and contribute to functional disability. However, the degree to which general and specific cognitive deficits affect everyday functioning in bipolar disorder is unknown. The goal of this meta-analysis was to examine the magnitude of the effect of specific neurocognitive abilities on everyday functioning in bipolar disorder.

METHODS

We conducted a comprehensive meta-analysis of studies that reported associations between performance on objective neuropsychological tasks and everyday functioning among individuals with bipolar disorder. From an initial pool of 486 papers, 22 studies met inclusion criteria, comprising a total of 1344 participants. Correlation coefficients were calculated for 11 cognitive domains and four measurement modalities for functioning. We also examined effect moderators, such as sample age, clinical state, and study design.

RESULTS

The mean Pearson correlation between neurocognitive ability and functioning was 0.27, and was significant for all cognitive domains and varied little by cognitive domain. Correlations varied by methods of everyday functioning assessment, being lower for clinician and self-report than performance-based tasks and real-world milestones such as employment. None of the moderator analyses were significant.

CONCLUSIONS

Overall, the strength of association between cognitive ability and everyday functioning in bipolar disorder is strikingly similar to that seen in schizophrenia, with little evidence for differences across cognitive domains. The strength of association differed to a greater extent according to functional measurement approach.

Effects of a mis-sense DISC1 variant on brain activation in two cohorts at high risk of bipolar disorder or schizophrenia

Bipolar disorder and schizophrenia share a number of clinical features and genetic risk variants of small effect, suggesting overlapping pathogenic mechanisms. The effect of single genetic risk variants on brain function is likely to differ in people at high familial risk versus controls as these individuals have a higher overall genetic loading and are therefore closer to crossing a threshold of disease liability. Therefore, whilst the effects of genetic risk variants on brain function may be similar across individuals at risk of both disorders, they are hypothesized to differ compared to that seen in control subjects. We sought to examine the effects of the DISC1 Leu(607) Phe polymorphism on brain activation in young healthy individuals at familial risk of bipolar disorder (n = 84), in a group of controls (n = 78), and in a group at familial risk of schizophrenia (n = 47), performing a language task. We assessed whether genotype effects on brain activation differed according to risk status. There was a significant genotype × group interaction in a cluster centered on the left pre/postcentral gyrus, extending to the inferior frontal gyrus. The origin of this genotype × group effect originated from a significant effect of the presumed risk variant (Phe) on brain activation in the control group, which was absent in both high-risk groups. Differential effects of this polymorphism in controls compared to the two familial groups suggests a commonality of effect across individuals at high-risk of the disorders, which is likely to be dependant upon existing genetic background.

Cognitive impairments in schizophrenia and schizoaffective disorder: relationship with clinical characteristics

The present study aimed to compare population-based familial samples of patients with schizophrenia (n = 218) and schizoaffective disorder (n = 62) and a healthy control group (n = 123). Patients with schizoaffective disorder outperformed patients with schizophrenia in verbal ability, processing speed, visual working memory, and verbal memory. When compared with controls, patients with schizoaffective disorder also had a generalized cognitive impairment. Adjusting for clinical characteristics removed significant differences between the patient groups. Irrespective of the diagnosis, patients with the most severe negative symptoms and highest dose of antipsychotics had the most severe cognitive impairments, whereas mood symptoms were not related to cognitive performance. In conclusion, people with schizoaffective disorder have severe cognitive impairments, but the impairments are milder than in schizophrenia. Mood symptoms may not explain the difference between the diagnostic groups in cognitive functions, but the difference may be related to differences in the severity of negative symptoms.

Lack of cortico-limbic coupling in bipolar disorder and schizophrenia during emotion regulation

Bipolar disorder (BD) and schizophrenia (Sz) share dysfunction in prefrontal inhibitory brain systems, yet exhibit distinct forms of affective disturbance. We aimed to distinguish these disorders on the basis of differential activation in cortico-limbic pathways during voluntary emotion regulation. Patients with DSM-IV diagnosed Sz (12) or BD-I (13) and 15 healthy control (HC) participants performed a well-established emotion regulation task while undergoing functional magnetic resonance imaging. The task required participants to voluntarily upregulate or downregulate their subjective affect while viewing emotionally negative images or maintain their affective response as a comparison condition. In BD, abnormal overactivity (hyperactivation) occurred in the right ventrolateral prefrontal cortex (VLPFC) during up- and downregulation of negative affect, relative to HC. Among Sz, prefrontal hypoactivation of the right VLPFC occurred during downregulation (opposite to BD), whereas upregulation elicited hyperactivity in the right VLPFC similar to BD. Amygdala activity was significantly related to subjective negative affect in HC and BD, but not Sz. Furthermore, amygdala activity was inversely coupled with the activity in the left PFC during downregulation in HC (r=-0.76), while such coupling did not occur in BD or Sz. These preliminary results indicate that differential cortico-limbic activation can distinguish the clinical groups in line with affective disturbance: BD is characterized by ineffective cortical control over limbic regions during emotion regulation, while Sz is characterized by an apparent failure to engage cortical (hypofrontality) and limbic regions during downregulation.

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.

How genes and environmental factors determine the different neurodevelopmental trajectories of schizophrenia and bipolar disorder

The debate endures as to whether schizophrenia and bipolar disorder are separate entities or different manifestations of a single underlying pathological process. Here, we argue that this sterile argument obscures the fact that the truth lies somewhere in between. Thus, recent studies support a model whereby, on a background of some shared genetic liability for both disorders, patients with schizophrenia have been subject to additional genetic and/or environmental factors that impair neurodevelopment; for example, copy number variants and obstetric complications are associated with schizophrenia but not with bipolar disorder. As a result, children destined to develop schizophrenia show an excess of neuromotor delays and cognitive difficulties while those who later develop bipolar disorder perform at least as well as the general population. In keeping with this model, cognitive impairments and brain structural abnormalities are present at first onset of schizophrenia but not in the early stages of bipolar disorder. However, with repeated episodes of illness, cognitive and brain structural abnormalities accumulate in both schizophrenia and bipolar disorder, thus clouding the picture.

Cognition in schizophrenia: core psychological and neural mechanisms

The challenge in understanding cognitive impairment in schizophrenia is that people with this illness have deficits in an array of domains. Here, we briefly review evidence regarding the pattern of deficits within three domains: context processing, working memory and episodic memory. We suggest that there may be a common mechanism driving deficits in these domains - an impairment in the ability to actively represent goal information in working memory to guide behavior, a function we refer to as proactive control. We suggest that such deficits in proactive control reflect impairments in dorsolateral prefrontal cortex, its interactions with other brain regions, such as parietal cortex, thalamus and striatum, and the influence of neurotransmitter systems, such as dopamine, GABA and glutamate.

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.

Neurocognitive impairment across the bipolar spectrum

Bipolar disorder is a severe mental illness that affects nearly 4.4% of the general population when bipolar spectrum disorders are taken into account. Neurocognitive impairment is thought to be a core deficit of this illness since it is present during euthymia. In fact, 40-60% of euthymic patients present with neurocognitive disturbances. Not only the clinical factors but also disturbances in neurocognition can influence the functional outcome of BD patients. Hence, further research is needed in order to clarify the relationship between these variables. Despite the growing body of evidence that has emerged during the last decade, no unique neurocognitive profile has been proposed yet for either BD subtype. The majority of the studies recluted heterogeneous samples (including both bipolar I and II) or focused on BD-I patients only. The aim of this review is to give an overall picture of the main neurocognitive disturbances found in the bipolar spectrum and particularly in BD-II, where the findings are more ambiguous. An extensive review of all the literature has been done regarding this subtype (from 1980 until July 2009). Data available until now suggest that deficits are present across the bipolar spectrum (BD-I and BD-II), but they seem slightly more severe in BD-I. The extent to which either subtype share-or not-some similarities is still unknown. More studies are required but it would also be interesting to reach a consensus in the neuropsychological assessment of BD to facilitate comparisons between the different studies.

Verbal and visual memory impairments among young offspring and healthy adult relatives of patients with schizophrenia and bipolar disorder: selective generational patterns indicate different developmental trajectories

OBJECTIVE

Memory deficits have been shown in patients affected by schizophrenia (SZ) and bipolar (BP)/mood disorder. We recently reported that young high-risk offspring of an affected parent were impaired in both verbal episodic memory (VEM) and visual episodic memory (VisEM). Understanding better the trajectory of memory impairments from childhood to adult clinical status in risk populations is crucial for early detection and prevention. In multigenerational families densely affected by SZ or BP, our aim was to compare the memory impairments observed in young nonaffected offspring with memory functioning in nonaffected adult relatives and patients.

METHODS

For 20 years, we followed up numerous kindreds in the Eastern Québec population. After having characterized the Diagnostic and Statistical Manual of Mental Disorders phenotypes, we assessed cognition (N = 381) in 3 subsamples in these kindreds and in controls: 60 young offspring of a parent affected by SZ or BP, and in the adult generations, 92 nonaffected adult relatives and 40 patients affected by SZ or BP. VEM was assessed with the California Verbal Learning Test and VisEM with the Rey figures.

RESULTS

The VEM deficits observed in the offspring were also found in adult relatives and patients. In contrast, the VisEM impairments observed in the young offspring were present only in patients, not in the adult relatives.

CONCLUSION

Implications for prevention and genetic mechanisms can be drawn from the observation that VEM and VisEM would show distinct generational trajectories and that the trajectory associated with VisEM may offer a better potential than VEM to predict future risk of developing the disease.

Behavioral phenotyping of glutathione-deficient mice: relevance to schizophrenia and bipolar disorder

Redox-dysregulation represents a common pathogenic mechanism in schizophrenia (SZ) and bipolar disorder (BP). It may in part arise from a genetically compromised synthesis of glutathione (GSH), the major cellular antioxidant and redox-regulator. Allelic variants of the genes coding for the rate-limiting GSH synthesizing enzyme glutamate-cysteine-ligase modifier (GCLM) and/or catalytic (GCLC) subunit have been associated with SZ and BP. Using mice knockout (KO) for GCLM we have previously shown that impaired GSH synthesis is associated with morphological, functional and neurochemical anomalies similar to those in patients. Here we asked whether GSH deficit is also associated with SZ- and BP-relevant behavioral and cognitive anomalies. Accordingly, we subjected young adult GCLM-wildtype (WT), heterozygous and KO males to a battery of standard tests. Compared to WT, GCLM-KO mice displayed hyperlocomotion in the open field and forced swim test but normal activity in the home cage, suggesting that hyperlocomotion was selective to environmental novelty and mildly stressful situations. While spatial working memory and latent inhibition remained unaffected, KO mice showed a potentiated hyperlocomotor response to an acute amphetamine injection, impaired sensorymotor gating in the form of prepulse inhibition and altered social behavior compared to WT. These anomalies resemble important aspects of both SZ and the manic component of BP. As such our data support the notion that redox-dysregulation due to GSH deficit is implicated in both disorders. Moreover, our data propose the GCLM-KO mouse as a valuable model to study the behavioral and cognitive consequences of redox dysregulation in the context of psychiatric disease.

Cognitive functioning in severe psychiatric disorders: a general population study

In clinical samples, patients with severe psychiatric disorders are found to have cognitive impairments. Less is known whether this applies to samples derived from the general population. We aimed to study cognitive functioning in a population-based sample comprising individuals with schizophrenia, other non-affective psychoses, bipolar disorders, major depressive disorder, and controls derived from the same population. The current analysis was based on 148 persons with severe mental disorders and 66 control subjects, derived from the Psychoses in Finland study. All subjects were interviewed with SCID, and a neuropsychological test battery was administered. Subjects with schizophrenia had a generalized cognitive impairment (d = 0.43-1.07), while those with other non-affective psychoses were impaired in verbal memory and processing speed (d = 0.43-0.59). Subjects with bipolar disorders were not impaired. Unipolar major depressive disorder associated with slowed processing speed (d = 0.64). Our findings on cognitive impairments in subjects with schizophrenia and other non-affective psychoses derived from the general population support previous findings of a generalized cognitive dysfunction in these subjects. However, our results suggest that subjects with bipolar disorders from non-clinical populations may not have significant cognitive impairments. Our results emphasize the importance of using control samples derived from the same population and studied similarly as those with disorders in evaluating cognitive functioning of subjects with severe mental disorders.

Brief cognitive assessment instruments in schizophrenia and bipolar patients, and healthy control subjects: a comparison study between the Brief Cognitive Assessment Tool for Schizophrenia (B-CATS) and the Screen for Cognitive Impairment in Psychiatry (SCIP)

Cognitive impairment in schizophrenia and psychosis is ubiquitous and acknowledged as a core feature of clinical expression, pathophysiology, and prediction of functioning. However, assessment of cognitive functioning is excessively time-consuming in routine practice, and brief cognitive instruments specific to psychosis would be of value. Two screening tools have recently been created to address this issue, i.e., the Brief Cognitive Assessment Tool for Schizophrenia (B-CATS) and the Screen for Cognitive Impairment in Psychiatry (SCIP). The aim of this research was to examine the comparative validity of these two brief instruments in relation to a global cognitive score. 161 patients with psychosis (96 patients diagnosed with schizophrenia and 65 patients diagnosed with bipolar disorder) and 76 healthy control subjects were tested with both instruments to examine their concurrent validity relative to a more comprehensive neuropsychological assessment battery. Scores from the B-CATS and the SCIP were highly correlated in the three diagnostic groups, and both scales showed good to excellent concurrent validity relative to a Global Cognitive Composite Score (GCCS) derived from the more comprehensive examination. The SCIP-S showed better predictive value of global cognitive impairment than the B-CATS. Partial and semi-partial correlations showed slightly higher percentages of both shared and unique variance between the SCIP-S and the GCCS than between the B-CATS and the GCCS. Brief instruments for assessing cognition in schizophrenia and bipolar disorders, such as the SCIP-S and B-CATS, seem to be reliable and promising tools for use in routine clinical practice.

Differential effects of DAAO on regional activation and functional connectivity in schizophrenia, bipolar disorder and controls

Recent studies have identified DAAO as a probable susceptibility gene for schizophrenia and bipolar disorder. However, little is known about how this gene affects brain function to increase vulnerability to these disorders. We examined the impact of DAAO genotype (rs3918346) on brain function in patients with schizophrenia, patients with bipolar I disorder and healthy controls. We tested the hypothesis that a variation in DAAO genotype would be associated with altered prefrontal function and altered functional connectivity in schizophrenia and bipolar disorder. We used functional magnetic resonance imaging to measure brain responses during a verbal fluency task in a total of 121 subjects comprising 40 patients with schizophrenia, 33 patients with bipolar disorder and 48 healthy volunteers. We then used statistical parametric mapping (SPM) and psycho-physiological interaction (PPI) analyses to estimate the main effects of diagnostic group, the main effect of genotype, and their interaction on brain activation and on functional connectivity. Inferences were made at p<0.05, after correction for multiple comparisons across the whole brain. In the schizophrenia group relative to the control group, patients with one or two copies of the T allele showed lower deactivation in the left precuneus and greater activation in the right posterior cingulate gyrus than patients with two copies of the C allele. This diagnosis×genotype interaction was associated with differences in the functional connectivity of these two regions with other cortical and subcortical areas. In contrast, there were no significant effects of diagnosis or of genotype in comparisons involving bipolar patients. Our results suggest that genetic variation in DAAO has a significant impact on both regional activation and functional connectivity, and provide evidence for a diagnosis-dependent pattern of gene action.

Insight in bipolar disorder: associations with cognitive and emotional processing and illness characteristics

OBJECTIVE

To investigate the multifactorial relationship between illness insight, cognitive and emotional processes, and illness characteristics in bipolar disorder patients.

METHODS

Data from 85 euthymic or mildly to moderately depressed bipolar disorder patients were evaluated. Insight was measured using the Mood Disorder Insight Scale (total score and subscale scores: awareness of illness, symptom attribution, and need for treatment). Cognitive and emotional functioning was measured in four domains (processing speed, memory, executive functioning, and emotional learning) in addition to premorbid IQ. Illness characteristics were assessed using the Mini-International Neuropsychiatric Interview, the Questionnaire for Bipolar Disorder, and the Inventory of Depressive Symptomatology-self rating scale. Regression analyses were performed for the whole sample. Post-hoc, interactions with lifetime psychotic features (LPF) were statistically tested and if significant, analyses were repeated for patients with (n = 36) and without (n = 49) LPF separately.

RESULTS

In the whole group, better insight was associated with lower processing speed, better memory performance, increased emotional learning, higher level of depressive symptoms, and longer duration of illness. Patients with LPF had worse awareness of illness, but better symptom attribution than patients without LPF. No group differences for need for treatment and overall insight were found. Finally, processing speed significantly predicted subscores for symptom attribution in patients with LPF only.

CONCLUSIONS

Cognitive functioning as well as impairments in emotional learning and psychotic features independently contributes to impaired insight in bipolar disorder. Processing speed seems to be a key variable in the prediction of insight in patients with LPF and not in patients without LPF.

[Minimal emotional dysfunction and first impression formation in personality disorders]

"Minimal cerebral dysfunctions" are isolated impairments of basic mental functions, which are elements of complex functions like speech. The best described are cognitive dysfunctions such as reading and writing problems, dyscalculia, attention deficits, but also motor dysfunctions such as problems with articulation, hyperactivity or impulsivity. Personality disorders can be characterized by isolated emotional dysfunctions in relation to emotional adequacy, intensity and responsivity. For example, paranoid personality disorders can be characterized by continuous and inadequate distrust, as a disorder of emotional adequacy. Schizoid personality disorders can be characterized by low expressive emotionality, as a disorder of effect intensity, or dissocial personality disorders can be characterized by emotional non-responsivity. Minimal emotional dysfunctions cause interactional misunderstandings because of the psychology of "first impression formation". Studies have shown that in 100 ms persons build up complex and lasting emotional judgements about other persons. Therefore, minimal emotional dysfunctions result in interactional problems and adjustment disorders and in corresponding cognitive schemata.From the concept of minimal emotional dysfunctions specific psychotherapeutic interventions in respect to the patient-therapist relationship, the diagnostic process, the clarification of emotions and reality testing, and especially an understanding of personality disorders as impairment and "selection, optimization, and compensation" as a way of coping can be derived.

Schizoaffective disorder: a review of current research themes and pharmacological management

Despite a clear recognition of the existence of patients with co-morbid psychotic and mood symptoms, many studies conclude that schizoaffective disorder as a distinct diagnosis does not exist. Regardless of one's opinion on schizoaffective disorder, psychiatrists remain dependent on phenomenological descriptions for diagnosing psychiatric disorders, and these phenomenological criteria are also used for clinical trial entry. On the other hand, many psychiatrists prescribe for specific target symptoms and do not always rigidly follow diagnostic systems and, moreover, there have been very few trials that have specifically studied schizoaffective disorder. Despite recent intriguing work in epidemiology, genetics, neurocognition and electrophysiology, the diagnosis of schizoaffective disorder remains controversial. Taken together, these studies suggest that even if schizoaffective disorder exists as a separate diagnosis, it may not be useful clinically due to considerable variation in the general use of this term. It is possible that diagnostic criteria in the future will include genetic, imaging and electrophysiological components, and that this will allow for better differentiation of disease states among the heterogeneous pool of patients currently believed to have schizophrenia, schizoaffective disorder or bipolar disorder. Although it is likely that most, if not all, antipsychotics are effective for schizoaffective disorder, given recent regulatory approval of a specific antipsychotic agent for the acute treatment of schizoaffective disorder, greater attention is now being focused on the entity of schizoaffective disorder and potential treatment decisions. However, based on the limited extant evidence, it is not yet possible to make definitive treatment recommendations for schizoaffective disorder. Additional clinical trials that include other antipsychotics, mood stabilizers and antidepressants are desirable and necessary before clear and comprehensive evidence-based treatment recommendations can be made.

No association of Disrupted-in-Schizophrenia-1 variation with prefrontal function in patients with schizophrenia and bipolar disorder

The Disrupted-in-Schizophrenia-1 (DISC1) gene has been implicated in both schizophrenia and bipolar disorder by linkage and genetic association studies. Altered prefrontal cortical function is a pathophysiological feature of both disorders, and we have recently shown that variation in DISC1 modulates prefrontal activation in healthy volunteers. Our goal was to examine the influence of the DISC1 polymorphism Cys704Ser on prefrontal function in schizophrenia and bipolar disorder. From 2004 to 2008, patients with schizophrenia (N = 44), patients with bipolar disorder (N = 35) and healthy volunteers (N = 53) were studied using functional magnetic resonance imaging while performing a verbal fluency task. The effect of Cys704Ser on cortical activation was compared between groups as Cys704 carriers vs. Ser704 homozygotes. In contrast to the significant effect on prefrontal activation we had previously found in healthy subjects, no significant effect of Cys704Ser was detected in this or any other region in either the schizophrenia or bipolar groups. When controls were compared with patients with schizophrenia, there was a diagnosis by genotype interaction in the left middle/superior frontal gyrus [family-wise error (FWE) P = 0.002]. In this region, Ser704/ser704 controls activated more than Cys704 carriers, and there was a trend in the opposite direction in schizophrenia patients. In contrast to its effect in healthy subjects, variation in DISC1 Cys704Ser704 genotype was not associated with altered prefrontal activation in patients with schizophrenia or bipolar disorder. The absence of an effect in patients may reflect interactions of the effects of DISC1 genotype with the effects of other genes associated with these disorders, and/or with the effects of the disorders on brain function.

Pattern of neural responses to verbal fluency shows diagnostic specificity for schizophrenia and bipolar disorder

BACKGROUND

Impairments in executive function and language processing are characteristic of both schizophrenia and bipolar disorder. Their functional neuroanatomy demonstrate features that are shared as well as specific to each disorder. Determining the distinct pattern of neural responses in schizophrenia and bipolar disorder may provide biomarkers for their diagnoses.

METHODS

104 participants underwent functional magnetic resonance imaging (fMRI) scans while performing a phonological verbal fluency task. Subjects were 32 patients with schizophrenia in remission, 32 patients with bipolar disorder in an euthymic state, and 40 healthy volunteers. Neural responses to verbal fluency were examined in each group, and the diagnostic potential of the pattern of the neural responses was assessed with machine learning analysis.

RESULTS

During the verbal fluency task, both patient groups showed increased activation in the anterior cingulate, left dorsolateral prefrontal cortex and right putamen as compared to healthy controls, as well as reduced deactivation of precuneus and posterior cingulate. The magnitude of activation was greatest in patients with schizophrenia, followed by patients with bipolar disorder and then healthy individuals. Additional recruitment in the right inferior frontal and right dorsolateral prefrontal cortices was observed in schizophrenia relative to both bipolar disorder and healthy subjects. The pattern of neural responses correctly identified individual patients with schizophrenia with an accuracy of 92%, and those with bipolar disorder with an accuracy of 79% in which mis-classification was typically of bipolar subjects as healthy controls.

CONCLUSIONS

In summary, both schizophrenia and bipolar disorder are associated with altered function in prefrontal, striatal and default mode networks, but the magnitude of this dysfunction is particularly marked in schizophrenia. The pattern of response to verbal fluency is highly diagnostic for schizophrenia and distinct from bipolar disorder. Pattern classification of functional MRI measurements of language processing is a potential diagnostic marker of schizophrenia.

Associations of anhedonia and cognition in persons with schizophrenia spectrum disorders, their siblings, and controls

The aim of the current study was to investigate the levels of social and physical anhedonia, as measured with the Chapman Scales for social and physical anhedonia in groups of patients with schizophrenia spectrum psychosis (n = 91), their unaffected siblings (n = 105), and control subjects drawn from a general population (n = 67). The second aim was to explore the effect of physical and social anhedonia on neuropsychological variables. Subjects with schizophrenia spectrum disorder had significantly more anhedonia than population controls, but the unaffected siblings did not differ from controls. Subjects with schizophrenia spectrum disorders had generalized cognitive deficits. Unaffected sibling status predicted impairments in executive and performance speed measures. Elevated physical anhedonia associated with deficits in verbal functions, but this was not related to genetic liability to schizophrenia. In conclusion, social and physical anhedonia did not seem to mediate neuropsychological deficits of schizophrenia family members.

Neurocognitive dysfunction in bipolar and schizophrenia spectrum disorders depends on history of psychosis rather than diagnostic group

OBJECTIVES

Neurocognitive dysfunction is milder in bipolar disorders than in schizophrenia spectrum disorders, supporting a dimensional approach to severe mental disorders. The aim of this study was to investigate the role of lifetime history of psychosis for neurocognitive functioning across these disorders. We asked whether neurocognitive dysfunction in bipolar and schizophrenia spectrum disorders depends more on history of psychosis than diagnostic category or subtype.

METHODS

A sample of individuals with schizophrenia (n=102), schizoaffective disorder (n=27), and bipolar disorder (I or II) with history of psychosis (n=75) and without history of psychosis (n=61) and healthy controls (n=280), from a large ongoing study on severe mental disorder, were included. Neurocognitive function was measured with a comprehensive neuropsychological test battery.

RESULTS

Compared with controls, all 3 groups with a history of psychosis performed poorer across neurocognitive measures, while the bipolar group without a history of psychosis was only impaired on a measure of processing speed. The groups with a history of psychosis did not differ from each other but performed poorer than the group without a history of psychosis on a number of neurocognitive measures. These neurocognitive group differences were of a magnitude expected to have clinical significance. In the bipolar sample, history of psychosis explained more of the neurocognitive variance than bipolar diagnostic subtype.

CONCLUSIONS

Our findings suggest that neurocognitive dysfunction in bipolar and schizophrenia spectrum disorders is determined more by history of psychosis than by Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) diagnostic category or subtype, supporting a more dimensional approach in future diagnostic systems.

Are psychiatric diagnoses of psychosis scientific and useful? The case of schizophrenia

BACKGROUND

Insurance systems, scientific journals, professional groups, educational initiatives, regulatory bodies and organisation of services appear to be fixed in 19th century diagnostic metaphors for psychosis, providing natural protection against change. Furthermore, the existence of two separate diagnostic systems in psychiatry, DSM and ICD, produces a bias that is conservative rather than anti-conservative, reducing the probability of non-cosmetic change.

METHODS

A qualitative review of the validity, usefulness and acceptability of the diagnosis of 'schizophrenia', in order to assess possible discrepancies between actual diagnostic practice in mental health services and alternatives dictated by scientific evidence and societal developments.

RESULTS

A 21st century concept of psychotic disorder should refer to an experience that can be understood as a variation of normal human mentation that can be expressed quantitatively. For the purpose of diagnosis, use can be made of scientific evidence of specificity yielding high diagnostic likelihood ratios rather than evidence of weak mean differences yielding low diagnostic likelihood ratios. In the case of psychosis, the evidence appears to favour a syndromal system of classification combining categorical and dimensional representations. The concept of 'salience' has the potential to make the public recognise psychosis as relating to an aspect of human mentation and experience that is universal.

CONCLUSIONS

The debate about alternatives to diagnose expressions of psychosis is often misunderstood as a misguided attempt to change societal stigma. In reality, however, it is about reduction of iatrogenic stigma occasioned by the use of unscientific and mystifying terminology. Scientific and societal developments have largely caught up with diagnostic traditions applied to psychosis phenotypes and although the traditional diagnostic system is deeply ingrained in all aspects of clinical and academic activities, change is possible if professional bodies actively promote a modern system of evidence-based diagnostic practice.

Targeting the correct HDAC(s) to treat cognitive disorders

Changes in gene expression in the brain may underlie cognitive deficits inherent to normal aging and neurodegenerative disease. However, the mechanisms underlying pathological alterations in the brain transcriptome are incompletely understood. Epigenetic mechanisms such as DNA methylation and histone acetylation have been shown to be important for memory processes in the adult brain. There is accumulating evidence that altered chromatin plasticity and histone acetylation are also involved in cognitive aging, neurodegeneration, and neuropsychiatric diseases. Inhibitors of histone deacetylase (HDAC) exhibit neuroprotective and neuroregenerative properties in animal models of various brain diseases. As such, targeting of HDACs seems to be a promising therapeutic strategy. In this review, we discuss the specific roles of each HDAC protein and the possible function of distinct histone modifications. We hope that this knowledge will aid in the development of diagnostic tools and in designing more potent and specific treatment for neurological disorders targeting selective HDAC proteins.

Hyperactivity, startle reactivity and cell-proliferation deficits are resistant to chronic lithium treatment in adult Nr2e1(frc/frc) mice

The NR2E1 region on Chromosome 6q21-22 has been repeatedly linked to bipolar disorder (BP) and NR2E1 has been associated with BP, and more specifically bipolar I disorder (BPI). In addition, patient sequencing has shown an enrichment of rare candidate-regulatory variants. Interestingly, mice carrying either spontaneous (Nr2e1(frc) ) or targeted (Tlx(-) ) deletions of Nr2e1 (here collectively known as Nr2e1-null) show similar neurological and behavioral anomalies, including hypoplasia of the cerebrum, reduced neural stem cell proliferation, extreme aggression and deficits in fear conditioning; these are the traits that have been observed in some patients with BP. Thus, NR2E1 is a positional and functional candidate for a role in BP. However, no Nr2e1-null mice have been fully evaluated for behaviors used to model BP in rodents or pharmacological responses to drugs effective in treating BP symptoms. In this study we examine Nr2e1(frc/frc) mice, homozygous for the spontaneous deletion, for abnormalities in activity, learning and information processing, and cell proliferation; these are the phenotypes that are either affected in patients with BP or commonly assessed in rodent models of BP. The effect of lithium, a drug used to treat BP, was also evaluated for its ability to attenuate Nr2e1(frc/frc) behavioral and neural stem cell-proliferation phenotypes. We show for the first time that Nr2e1-null mice exhibit extreme hyperactivity in the open field as early as postnatal day 18 and in the home cage, deficits in open-field habituation and passive avoidance, and surprisingly, an absence of acoustic startle. We observed a reduction in neural stem/progenitor cell proliferation in Nr2e1(frc/frc) mice, similar to that seen in other Nr2e1-null strains. These behavioral and cell-proliferation phenotypes were resistant to chronic-adult-lithium treatment. Thus, Nr2e1(frc/frc) mice exhibit behavioral traits used to model BP in rodents, but our results do not support Nr2e1(frc/frc) mice as pharmacological models for BP.

Frontonasal dysmorphology in bipolar disorder by 3D laser surface imaging and geometric morphometrics: comparisons with schizophrenia

Any developmental relationship between bipolar disorder and schizophrenia engenders continuing debate. As the brain and face emerge in embryological intimacy, brain dysmorphogenesis is accompanied by facial dysmorphogenesis. 3D laser surface imaging was used to capture the facial surface of 13 male and 14 female patients with bipolar disorder in comparison with 61 male and 75 female control subjects and with 37 male and 32 female patients with schizophrenia. Surface images were analysed using geometric morphometrics and 3D visualisations to identify domains of facial shape that distinguish bipolar patients from controls and bipolar patients from those with schizophrenia. Both male and female bipolar patients evidenced significant facial dysmorphology: common to male and female patients was overall facial widening, increased width of nose, narrowing of mouth and upward displacement of the chin; dysmorphology differed between male and female patients for nose length, lip thickness and tragion height. There were few morphological differences in comparison with schizophrenia patients. That dysmorphology of the frontonasal prominences and related facial regions in bipolar disorder is more similar to than different from that found in schizophrenia indicates some common dysmorphogenesis. Bipolar disorder and schizophrenia might reflect similar insult(s) acting over slightly differing time-frames or slightly differing insult(s) acting over a similar time-frame.

Sustained attention as a potential endophenotype for bipolar disorder

OBJECTIVE

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

METHOD

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

RESULTS

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

CONCLUSION

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

The Schizophrenia Cognition Rating Scale: validation of an interview-based assessment of cognitive functioning in Asian patients with schizophrenia

Growing interest in cognitive deficits associated with schizophrenia has led to the need for a clinician-friendly cognitive instrument. The Schizophrenia Cognition Rating Scale (SCoRS), recognized for its brevity and ease of administration, has proven to be a valid and reliable measure of overall cognition in schizophrenia patients. However, there has been no such validation in an Asian context. This SCoRS validation study involved 103 patient and 48 control subjects within an Asian population. Test-retest reliability, sensitivity of the instrument to cognitive differences between patients with schizophrenia and healthy controls as well as validity by comparing with a standardised performance-based cognitive battery, the Brief Assessment of Cognition in Schizophrenia (BACS) were assessed. Our findings indicated that SCoRS is highly reliable (ICC=0.984) and sensitive to cognitive dysfunction. SCoRS is significantly correlated with BACS composite scores and predicted functional outcomes as measured by Global Assessment of Functioning (GAF) and World Health Organisation-Quality of Life (WHO QOL) within an Asian population. SCoRS represents a clinician-friendly cognitive assessment tool that incorporates third-party feedback and might be employed in clinical practice to better evaluate and manage schizophrenia.

The International Society for Bipolar Disorders-Battery for Assessment of Neurocognition (ISBD-BANC)

OBJECTIVES

Although cognitive impairment is recognized as an important clinical feature of bipolar disorder, there is no standard cognitive battery that has been developed for use in bipolar disorder research. The aims of this paper were to identify the cognitive measures from the literature that show the greatest magnitude of impairment in bipolar disorder, to use this information to determine whether the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB), developed for use in schizophrenia, might be suitable for bipolar disorder research, and to propose a preliminary battery of cognitive tests for use in bipolar disorder research.

METHODS

The project was conducted under the auspices of the International Society for Bipolar Disorders and involved a committee that comprised researchers with international expertise in the cognitive aspects of bipolar disorder. In order to identify cognitive tasks that show the largest magnitude of impairment in bipolar disorder, we reviewed the literature on studies assessing cognitive functioning (including social cognition) in bipolar disorder. We further provided a brief review of the cognitive overlap between schizophrenia and bipolar disorder and evaluated the degree to which tasks included in the MCCB (or other identified tasks) might be suitable for use in bipolar disorder.

RESULTS

Based on evidence that cognitive deficits in bipolar disorder are similar in pattern but less severe than in schizophrenia, it was judged that most subtests comprising the MCCB appear appropriate for use in bipolar disorder. In addition to MCCB tests, other specific measures of more complex verbal learning (e.g., the California Verbal Learning Test) or executive function (Stroop Test, Trail Making Test-part B, Wisconsin Card Sorting Test) also show substantial impairment in bipolar disorder.

CONCLUSIONS

Our analysis reveals that the MCCB represents a good starting point for assessing cognitive deficits in research studies of bipolar disorder, but that other tasks including more complex verbal learning measures and tests of executive function should also be considered in assessing cognitive compromise in bipolar disorder. Several promising cognitive tasks that require further study in bipolar disorder are also presented.

Cognitive impairment in patients with a schizoaffective disorder: a comparison with bipolar patients in euthymia

Objectives

Several studies have shown persistent neurocognitive impairment in patients with a bipolar affective disorder (BD) even in euthymia as well as in patients with a schizoaffective disorder (SAD). The aim of our study was to compare the neuropsychological performance between these two groups. Confounding variables were controlled to enhance our understanding of cognitive dysfunction in both BD and SAD.

Methods

Several domains of neurocognitive function, executive function, memory, attention, concentration and perceptuomotor function were examined in 28 euthymic SAD patients and 32 BD patients by using a neuropsychological test battery. The Hamilton Depression Rating Scale (HAMD), Montgomery-Asberg Depression Rating Scale (MADRS) and Young Mania Rating Scale (YMRS) were used to evaluate the patients' clinical status. Data analysis was performed by using a multivariate analysis of covariance (ANCOVA/MANCOVA).

Results

Euthymic SAD patients showed greater cognitive impairment than euthymic BD patients in the tested domains including declarative memory and attention. Putative significant group differences concerning cognitive flexibility vanished when controlled for demographic and clinical variables. Age and medication were robust predictors to cognitive performance of both SAD and BD patients.

Conclusions

Our results point out the worse cognitive outcome of SAD compared to BD patients in remission. Remarkably, the variance is higher for some of the test results between the groups than within each group, this being discussed in light of the contradictive concept of SAD.

Neuropsychological functioning in early-onset first-episode psychosis: comparison of diagnostic subgroups

The aims of this study were to examine the nature and extent of cognitive impairment in first-episode early-onset psychosis (FE-EOP) soon after their stabilisation and to search for potential differences according to specific diagnostic sub-groups of patients. As part of a Spanish multicentre longitudinal study, 107 FE-EOP patients and 98 healthy controls were assessed on the following cognitive domains: attention, working memory, executive functioning, and verbal learning and memory. Three diagnostic categories were established in the patient sample: schizophrenia (n = 36), bipolar disorder (n = 19), and other psychosis (n = 52). Patients performed significantly worse than controls in all cognitive domains. The three diagnostic sub-groups did not differ in terms of impaired/preserved cognitive functions or degree of impairment. FE-EOP patients show significant cognitive impairment that, during this early phase, seems to be non-specific to differential diagnosis.

Stroop and emotional Stroop interference in unaffected relatives of patients with schizophrenic and bipolar disorders: distinct markers of vulnerability?

Reduced inhibition has been demonstrated in both schizophrenic and bipolar patients through the findings of increased interference on the Stroop Colour-Word Task (SCWT) and increased emotional interference on specific versions of the Emotional Stroop Task (EST). Despite previous findings of enhanced interference in unaffected relatives of schizophrenic and bipolar patients, it remains unclear whether interference might be a candidate endophenotype to both disorders. Moreover, data regarding emotional interference in unaffected relatives are critically lacking. In the present study, we aimed to compare unaffected relatives of patients with schizophrenia (SZ-rel, N = 30) and bipolar disorder (BD-rel, N= 30) with normal controls (N = 60) when performing the SCWT and an EST designed with neutral, depressive, paranoid and manic words. SZ-rel exhibited greater interference effect on both the SCWT and the EST as compared to either BD-rel or normal controls. BD-rel, and by contrast to SZ-rel and controls, showed increased emotional interference effect on the EST that was specifically associated to the disease-related words. The findings support the hypothesis of different markers of vulnerability to schizophrenic and bipolar disorders; impairment in cognitive inhibition could characterize high-risk individuals for schizophrenia whereas an emotional bias towards mood-related information could be a trait marker of bipolar disease.

Use of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) to investigate group and gender differences in schizophrenia and bipolar disorder

OBJECTIVE

Gender differences exist in schizophrenia and bipolar disorder (BD), therefore the aim of the present study was to clarify the role of gender in cognitive deficits in these disorders.

METHODS

Cognitive performance was examined in schizophrenia (24M : 14F) and BD (16M : 24F) patients compared with age-, IQ- and gender-matched control participants (21M : 22F). The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was used to assess five cognitive domains: immediate memory/learning, visuospatial ability, language, attention, and delayed memory, which are summed to provide a Total score.

RESULTS

In comparison to controls, schizophrenia patients showed deficits on all domains, while BD patients had impaired immediate memory/learning, language and Total score. Schizophrenia patients showed deficits compared to BD in the Total score, immediate and delayed memory and visuospatial ability. The Total and domain scores were not different in men and women across or within groups. There were gender effects on four of the 12 individual cognitive tasks, in which female patients outperformed male patients. Further, there were gender differences across groups for three of the individual tasks: female schizophrenia patients showed poorer story memory and story recall compared to male schizophrenia patients; female BD patients had enhanced figure copy performance compared to male BD patients.

CONCLUSIONS

The RBANS highlighted the cognitive deficits in schizophrenia and BD patients compared to controls and also each other. There were no overall gender differences in cognition.

Symptoms of psychosis in anorexia and bulimia nervosa

Despite evidence from case series, the comorbidity of eating disorders with psychosis is less investigated than their comorbidity with anxiety and mood disorders. We investigated the occurrence of symptoms of psychosis in 112 female patients diagnosed with DSM-IV eating disorders (anorexia nervosa=61, bulimia nervosa=51) and 631 high school girls in the same health district as the patients: the items of the SCL-90R symptom dimensions "paranoid ideation" and "psychoticism" were specifically examined. No case of co-morbid schizophrenia was observed among patients. Compared with controls, the patients with anorexia nervosa were more likely to endorse the item "Never feeling close to another person"; the patients with bulimia nervosa were more likely to endorse the item "Feeling others are to blame for your troubles". Both groups of patients were more likely than controls to endorse the item "Idea that something is wrong with your mind". The students who were identified by the EAT and the BITE as being "at risk" for eating disorders were more likely to assign their body a causative role in their problems. Symptoms of psychosis can be observed in patients with eating disorders, but these could be better explained within the psychopathology of the disorders rather than by assuming a link with schizophrenia.

Cognitive impairment in schizophrenia and affective psychoses: implications for DSM-V criteria and beyond

It has recently been suggested that the diagnostic criteria of schizophrenia should include specific reference to cognitive impairments characterizing the disorder. Arguments in support of this assertion contend that such inclusion would not only serve to increase the awareness of cognitive deficits in affected patients, among both clinicians and researchers alike, but also increase the "point of rarity" between schizophrenia and mood disorders. The aim of the current article is to examine this latter assertion in light of the recent opinion piece provided by Keefe and Fenton (Keefe RSE, Fenton WS. How should DSM-V criteria for schizophrenia include cognitive impairment? Schizophr Bull. 2007;33:912-920). Through literature review, we explore the issue of whether cognitive deficits do in fact differentiate the major psychoses. The overall results of this inquiry suggest that inclusion of cognitive impairment criteria in Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) (DSM-V) would not provide a major advancement in discriminating schizophrenia from bipolar disorder and affective psychoses. Therefore, while cognitive impairment should be included in DSM-V, it should not dictate diagnostic specificity--at least not until more comprehensive evidence-based reviews of the current diagnostic system have been undertaken. Based on this evidence, we consider several alternatives for the DSM-V definition of cognitive impairment in schizophrenia, including (1) the inclusion of cognitive impairment as a specifier and (2) the definition of cognitive impairment as a dimension within a hybrid categorical-dimensional system. Given the state of current evidence, these possibilities appear to represent the most parsimonious approaches to the inclusion of cognitive deficits in the diagnostic criteria of schizophrenia and, potentially, of mood disorders.

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.

Alterações cognitivas na esquizofrenia: atualização

As alterações cognitivas são características centrais na esquizofrenia. Elas permanecem relativamente estáveis durante todo o curso da doença, não sendo secundárias a outros sintomas ou a efeitos colaterais de psicofármacos. Estão diretamente ligadas a prejuízo funcional e a pior qualidade de vida dos pacientes. Diversos estudos vêm sendo realizados no sentido de caracterizar as principais alterações cognitivas na esquizofrenia, identificar suas bases neurobiológicas e padronizar instrumentos de pesquisa, fundamentais para o advento de novos alvos para intervenções farmacológicas na esquizofrenia. O objetivo deste trabalho foi fazer uma atualização sobre o assunto.

The psychoses: cluster 3 of the proposed meta-structure for DSM-V and ICD-11

BACKGROUND

In an effort to group mental disorders on the basis of etiology, five clusters have been proposed. Here we consider the validity of the cluster comprising selected psychotic and related disorders.

METHOD

A group of diagnostic entities classified under schizophrenia and other psychotic disorders in DSM-IV-TR were assigned to this cluster and the bordering disorders, bipolar (BD) and schizotypal personality disorders (SPD), were included. We then reviewed the literature in relation to 11 validating criteria proposed by the DSM-V Task Force Study Group.

RESULTS

Relevant comparisons on the 11 spectrum criteria are rare for the included disorders except for schizophrenia and the two border conditions, BD and SPD. The core psychosis group is congruent at the level of shared psychotic psychopathology and response to antipsychotic medication. BD and SPD are exceptions in that psychosis is not typical in BD-II disorder and frank psychosis is excluded in SPD. There is modest similarity between schizophrenia and BD relating to risk factors, neural substrates, cognition and endophenotypes, but key differences are noted. There is greater support for a spectrum relationship of SPD and schizophrenia. Antecedent temperament, an important validator for other groupings, has received little empirical study in the various psychotic disorders.

CONCLUSIONS

The DSM-IV-TR grouping of psychotic disorders is supported by tradition and shared psychopathology, but few data exist across these diagnoses relating to the 11 spectrum criteria. The case for including BD is modest, and the relationship of BD to other mood disorders is addressed elsewhere. Evidence is stronger for inclusion of SPD, but the relationship with other personality disorders along the 11 criteria is not addressed and the absence of psychosis presents a conceptual problem. There are no data along the 11 spectrum criteria that are decisive for a cluster based on etiology, and inclusion of BD and SPD is questionable.

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.

'Salience syndrome' replaces 'schizophrenia' in DSM-V and ICD-11: psychiatry's evidence-based entry into the 21st century?

OBJECTIVE

Japan was the first country to abandon the 19th century term of 'mind-splitting disease' (schizophrenia). Revisions of DSM and ICD are forthcoming. Should the rest of the world follow Japan's example?

METHOD

A comprehensive literature search was carried out in order to review the scientific evidence for the validity, usefulness and acceptability of current concepts of psychotic disorder.

RESULTS

The discussion about re-classifying and renaming schizophrenia and other psychotic disorders is clouded by conceptual confusion. First, it is often misunderstood as a misguided attempt to change societal stigma instead of an attempt to change iatrogenic stigma occasioned by the use of misleading and mystifying terminology. Second, the debate is misunderstood as purely semantic, whereas in actual fact it is about the core concepts underlying psychiatric nosology. Third, it has been suggested that the debate is political. However, solid scientific evidence pointing to the absence of nosological validity of diagnostic categories lies at the heart of the argument. Fourth, there is confusion about what constitutes a syndrome (a group of symptom dimensions that cluster in different combinations in different people and for which one or more underlying diseases may or may not be found) and a disease (a nosologically valid entity with specific causes, symptoms, treatment and course).

CONCLUSION

Scientific evidence favours a syndromal system of classification combining categorical and dimensional representations of psychosis. The concept of 'salience' has the potential to make the public recognize psychosis as relating to an aspect of human mentation and experience that is universal. It is proposed to introduce, analogous to the functional-descriptive term 'Metabolic syndrome', the diagnosis of 'Salience syndrome' to replace all current diagnostic categories of psychotic disorders. Within Salience syndrome, three subcategories may be identified, based on scientific evidence of relatively valid and specific contrasts, named Salience syndrome with affective expression, Salience syndrome with developmental expression and Salience syndrome not otherwise specified.

Comparative study of neurocognitive function in euthymic bipolar patients and stabilized schizophrenic patients

Few studies have compared neurocognitive performance in euthymic patients with bipolar disorder (BD), stabilized patients with schizophrenia (SC) and normal controls (NC) using a comprehensive neuropsychological battery, and those that have been conducted have yielded discrepant results. We evaluated the neurocognitive profile shown by 73 euthymic patients with BD, 89 stabilized patients with SC and 67 NC. All participants completed a cognitive battery in which the domains evaluated were executive functioning, sustained attention, and verbal and visual memory. Individuals with BD were administered the Quality of Life Scale (QLS). Patients with BD manifested dysfunction in executive functioning (moderate-to-large effect size), sustained attention (moderate effect size) and verbal/visual memory (large effect size) compared with NC. Verbal memory deficit in patients with BD was related to poor functional outcome on the QLS and Global Assessment of Functioning (GAF). Patients with BD performed significantly better than patients with SC on the Trail Making Test (TMT) part B, backward digit span, and California Verbal Learning Test (CVLT) learning trials. Other neuropsychological measures showed no significant differences between the two patient groups. These findings support the notion that euthymic BD patients suffer from an extensive neurocognitive deficit that affects all cognitive domains and is qualitatively similar to that in SC patients. Persistent verbal memory impairment in BD has clinical relevance because it is associated with poor psychosocial function.

A comparison of the CogState Schizophrenia Battery and the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Battery in assessing cognitive impairment in chronic schizophrenia

This study examined the criterion and construct validity of a brief computerized cognitive test battery (CogState Schizophrenia Battery) compared to a conventional cognitive test battery recommended by the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) consensus. The CogState and MATRICS batteries yielded comparable effect sizes in comparing patients with schizophrenia to healthy controls (Cohen's ds = -1.50 for both batteries). Moderate to large correlations were observed between CogState and MATRICS measures of processing speed, attention/vigilance, working memory, verbal and visual learning, reasoning/problem solving, and social cognition (rs = .56-.79). CogState and MATRICS composite scores also correlated strongly with scores on the University of California at San Diego (UCSD) Performance-Based Skills Assessment (UPSA; rs = .76 and .79, respectively) in patients with schizophrenia. Results of this study suggest that the CogState Schizophrenia Battery provides valid measurement of the cognitive domains nominated by the MATRICS consensus group as being important to consider in the context of pharmacological treatments for cognitive impairment in schizophrenia.

Increased inferior frontal activation during word generation: a marker of genetic risk for schizophrenia but not bipolar disorder?

During verbal-fluency tasks, impairments in performance and functional abnormalities in the inferior frontal cortex have been observed in both schizophrenia patients and their unaffected relatives. We sought to examine whether such functional abnormalities are a specific marker of genetic vulnerability to schizophrenia. We studied a sample of 132 subjects, comprising 39 patients with schizophrenia, 10 unaffected monozygotic (MZ) cotwins of schizophrenia probands, 28 patients with bipolar disorder, 7 unaffected MZ cotwins of bipolar disorder probands and 48 healthy controls. Blood oxygen level-dependent response was measured using functional magnetic resonance imaging during the performance of an overt verbal-fluency task with two levels of task difficulty, in a cytoarchitectonic region of interest encompassing Brodmann areas 44 and 45 bilaterally. Patients with schizophrenia and the unaffected MZ cotwins of schizophrenia probands showed increased activation in the inferior frontal cortex relative to healthy controls and bipolar patients. Increased engagement of the inferior frontal cortex during verbal-fluency may thus be a marker of genetic vulnerability to schizophrenia.

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.

Will the Kraepelinian dichotomy survive DSM-V?

Kraepelin proposed dementia praecox and manic-depressive illness as the two major psychotic disorders. This paradigm is still prevalent, but observations of overlapping boundaries between bipolar disorder and schizophrenia challenge this dichotomy. However, the concept of schizophrenia has been radically altered from the original Kraepelinian proposal. We defend the two psychoses positions, but suggest two flaws in the heuristic application: (1) overlapping features, such as psychotic symptoms, are not decisive in differential diagnosis; and (2) each disorder is a syndrome, not a disease entity. An alternative paradigm based on domains of pathology is more powerful for studies of etiology, pathophysiology, and therapeutic discovery.

Neuropsychological abnormalities in schizophrenia and major mood disorders: similarities and differences

The past 20 years have been witness to a growing knowledge base of research highlighting the critical importance of cognition in understanding functional status and outcome in schizophrenia. This work has led to an increased emphasis on identifying and evaluating treatments that enhance cognition in schizophrenia, with the hope that this would translate into a better quality of life and improved outcome for patients. At the same time, this research has raised new questions about the specificity of cognitive impairments to schizophrenia and the degree to which similar cognitive impairments may be present in other disorders that can involve psychotic symptoms (eg, schizoaffective disorder, bipolar disorder, and psychotic major depression). This article provides a brief overview of work comparing cognitive function across the nonaffective and affective psychoses and highlights areas of similarity and dissimilarity in the role cognition plays in these disorders.

Identifying and treating cognitive impairment in bipolar disorder

OBJECTIVES

The presence of cognitive deficits has become increasingly appreciated across all phases of bipolar disorder. The present review sought to identify domains of cognitive dysfunction, methods of assessment, discrimination of iatrogenic from illness-specific etiologies, and pharmacologic strategies to manage cognitive problems in patients with bipolar disorder.

METHODS

A selective literature review was performed focusing on studies of descriptive phenomenology and pharmacologic intervention (favoring randomized comparisons when existent but open trials or case reports when not) involving cognition in bipolar disorder populations, healthy volunteers, or other clinical populations. Identification was made of (i) practical strategies for clinical assessment and management of cognitive complaints, (ii) limitations of existing intervention studies, and (iii) recommendations for the design and direction of future research.

RESULTS

Cognitive deficits involving attention, executive function, and verbal memory are evident across all phases of bipolar disorder. Most existing treatment studies involve nonbipolar populations, prompting caution when extrapolating outcomes to individuals with bipolar disorder. Differentiating medication- from illness-induced cognitive dysfunction requires comprehensive assessment with an appreciation for the cognitive domains most affected by specific medications. No current pharmacotherapies substantially improve cognition in bipolar disorder, although preliminary findings suggest some potential value for adjunctive stimulants such as modafinil and novel experimental agents.

CONCLUSIONS

Circumscribed cognitive deficits may be both iatrogenic and intrinsic to bipolar disorder. Optimal management hinges on a knowledge of illness-specific cognitive domains as well as of the beneficial or adverse cognitive profiles of common psychotropic medications.