Making progress in schizophrenia research

Familial Risk for Schizophrenia vs Bipolar Disorder and Task-Based Neural Activation: A functional Magnetic Resonance Imaging Meta-Analysis

BACKGROUND AND HYPOTHESIS

Individuals at familial risk for developing schizophrenia (FRSZ) or bipolar disorder (FRBD) have shared and unique genetic risks. Few studies have compared neural activation between these two groups. Therefore, the present meta-analysis investigated functional brain similarities and differences between FRSZ and FRBD individuals.

STUDY DESIGN

A systematic literature review was conducted of articles that compared FRSZ or FRBD individuals to healthy controls (31 FRSZ and 22 FRBD). Seed-based d mapping was used to conduct the meta-analysis. Analyses included comparisons of FRSZ to controls, FRBD to controls, and both relative groups to each other.

STUDY RESULTS

Using a highly conservative family-wise error rate correction, there were no significant findings. Using a less conservative threshold, FRSZ compared to controls had lower activation in the left precuneus (Puncorrected = .02) across all studies and in the left middle frontal gyrus (Puncorrected = .03) in nonsocial cognition studies. FRBD compared to controls had lower activation in the left superior parietal gyrus (Puncorrected = .03) and right angular gyrus (Puncorrected = .03) in nonsocial cognition studies, and higher activation in the left superior frontal gyrus (Puncorrected = .01) in social tasks. Differences between FRSZ and FRBD were not significant.

CONCLUSIONS

There were few robust differences between FRSZ or FRBD compared to controls. This suggests only weak support for neural activation differences between individuals at genetic risk for schizophrenia or bipolar disorder and controls. The tentative findings observed were in different brain regions for FRSZ and FRBD, with no strong evidence for shared effects between schizophrenia and bipolar genetic risk on neural activation.

The factor structure and clinical utility of clinician-rated dimensions of psychosis symptom severity in patients with recent-onset psychosis: Results of a 1-year longitudinal follow-up prospective cohort study

The classic subtype classification of schizophrenia has been removed, and DSM-5 now includes the Clinician-Rated Dimensions of Psychosis Symptom Severity (CRDPSS). In the present study, a factor analysis of the CRDPSS was performed, and we assessed whether patient classification using the derived factor structure helps predict the clinical course. The participants were 390 patients with recent-onset psychosis enrolled in the Korean Early Psychosis Cohort Study (KEPS). Two factors were identified: psychotic (including delusions, hallucinations, disorganization, and abnormal psychomotor behavior) and negative-cognitive (including negative symptoms and impaired cognition). Patients were grouped based on the factor structure and changes in clinical course were monitored over 1 year. The negative-cognitive group demonstrated longer duration of untreated psychosis, earlier onset, and a higher rate of psychiatric comorbidities. Baseline Positive and Negative Syndrome Scale (PANSS) total and Clinical Global Impression-Severity (CGI-S) scores were higher in psychotic group, but group differences were not observed after 2 months. Conversely, the PANSS negative scale score was significantly higher in negative-cognitive group throughout follow-up, and CGI-S score was reversed at 12 months. The findings indicate that the factor structure derived herein for the CRDPSS could be helpful for predicting the clinical course of recent-onset psychosis patients.

Validity, reliability and clinical utility of mental disorders: The case of ICD-11 schizophrenia

Diagnostic classification systems categorise mental psychopathology in mental disorders. Although these entities are clinical constructs developed by consensus, it has been pointed out that in practice they are usually managed as natural entities and without evaluating aspects related to their nosological construction. The objectives of the study are to review a) the conceptualisation of mental disorders, b) the indicators of validity, reliability and clinical utility, and c) the values ​​of these indicators in ICD-11 schizophrenia. The results show that mental disorders are conceptualised as discrete entities, like the diseases of other areas of medicine; however, differences are observed between these diagnostic categories in clinical practice. The reliability and clinical utility of mental disorders are adequate; however, the validity is not yet clarified. Similarly, ICD-11 schizophrenia demonstrates adequate reliability and clinical utility, but its validity remains uncertain. The conceptualisation of psychopathology in discrete entities may be inadequate for its study, therefore dimensional and mixed models have been proposed. The indicators of validity, reliability and clinical utility enable us to obtain an accurate view of the nosological state of mental disorders when evaluating different aspects of their nosological construction.

Validity, Reliability and Clinical Utility of Mental Disorders: The Case of ICD-11 Schizophrenia

Diagnostic classification systems categorise mental psychopathology in mental disorders. Although these entities are clinical constructs developed by consensus, it has been pointed out that in practice they are usually managed as natural entities and without evaluating aspects related to their nosological construction. The objectives of the study are to review a) the conceptualisation of mental disorders, b) the indicators of validity, reliability and clinical utility, and c) the values of these indicators in ICD-11 schizophrenia. The results show that mental disorders are conceptualised as discrete entities, like the diseases of other areas of medicine; however, differences are observed between these diagnostic categories in clinical practice. The reliability and clinical utility of mental disorders are adequate; however, the validity is not yet clarified. Similarly, ICD-11 schizophrenia demonstrates adequate reliability and clinical utility, but its validity remains uncertain. The conceptualisation of psychopathology in discrete entities may be inadequate for its study, therefore dimensional and mixed models have been proposed. The indicators of validity, reliability and clinical utility enable us to obtain an accurate view of the nosological state of mental disorders when evaluating different aspects of their nosological construction.

The evolution of Kraepelin's nosological principles

Emil Kraepelin developed a new psychiatric nosology in the eight editions of his textbook. Previous papers have explored his construction of particular diagnoses, including dementia praecox and manic-depressive insanity. Here we are providing a close reading of his introductory textbook chapter, that presents his general principles of nosology. We identify three phases: 1) editions 1-4, in which he describes nosological principles in search of data; 2) editions 5-7, in which he declares the mature version of his nosological principles and develops new disease categories; 3) edition 8, in which he qualifies his nosological claims and allows for greater differentiation of psychiatric disorders. We propose that Kraepelin's nosology is grounded in three principles. First, psychiatry, like other sciences, deals with natural phenomena. Second, mental states cannot be reduced to neural states, but science will progress and will, ultimately, reveal how nature creates abnormal mental states and behavior. Third, there is a hierarchy of validators of psychiatric diagnoses, with the careful study of clinical features (signs, symptoms and course) being more important than neuropathologic and etiological studies. These three principles emerged over the course of the eight editions of Kraepelin's textbook and were informed by his own research and by available scientific methods. His scientific views are still relevant today: they have generated and, at the same time, constrained our current psychiatric nosology.

Schizophrenia in ICD-11: Comparison of ICD-10 and DSM-5

The conceptualization of schizophrenia has changed from its initial conception in the 19th century to the recent publication of the ICD-11. The changes incorporated in this latest version were made based on the evaluation of the current ICD, the available scientific evidence, and the consensus reached by its developers. In this paper we describe the conceptualization changes (diagnostic criteria and specifiers) of ICD-11 schizophrenia with respect to those of ICD-10 and DSM-5. The changes found are discussed based on the scientific literature published in Medline, Scopus and Scielo until July 2019 and the information on the Wordl Health Organization and American Psychiatric Association websites. Given that the diagnosis of schizophrenia is based on the diagnostic criteria of the diagnostic classification systems, it is important to know the changes made in its conceptualization and the evidence supporting such modifications.

Wernicke-Kleist-Leonhard phenotypes of endogenous psychoses: a review of their validity

While the ICD-DSM paradigm has been a major advance in clinical psychiatry, its usefulness for biological psychiatry is debated. By defining consensus-based disorders rather than empirically driven phenotypes, consensus classifications were not an implementation of the biomedical paradigm. In the field of endogenous psychoses, the Wernicke-Kleist-Leonhard (WKL) pathway has optimized the descriptions of 35 major phenotypes using common medical heuristics on lifelong diachronic observations. Regarding their construct validity, WKL phenotypes have good reliability and predictive and face validity. WKL phenotypes come with remarkable evidence for differential validity on age of onset, familiality, pregnancy complications, precipitating factors, and treatment response. Most impressive is the replicated separation of high- and low-familiality phenotypes. Created in the purest tradition of the biomedical paradigm, the WKL phenotypes deserve to be contrasted as credible alternatives with other approaches currently under discussion.
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Structure and neural mechanisms of catatonia

Catatonia is a psychomotor syndrome associated with several psychiatric and medical conditions. Psychomotor signs range from stupor to agitation, and include pathognomonic features such as verbigeration and waxy flexibility. Disturbances of volition led to the classification of catatonia as a subtype of schizophrenia, but changes in nosology now recognise the high prevalence in mood disorders, overlap with delirium, and comorbidity with medical conditions. Initial psychometric studies have revealed three behavioural factors, but the structure of catatonia is still unknown. Evidence from brain imaging studies of patients with psychotic disorders indicates increased neural activity in premotor areas in patients with hypokinetic catatonia. However, whether this localised hyperactivity is due to corticocortical inhibition or excess activity of inhibitory corticobasal ganglia loops is unclear. Current treatment of catatonia relies on benzodiazepines and electroconvulsive therapy-both effective, yet unspecific in their modes of action. Longitudinal research and treatment studies, with neuroimaging and brain stimulation techniques, are needed to advance our understanding of catatonia.

Similar white matter changes in schizophrenia and bipolar disorder: A tract-based spatial statistics study

Several strands of evidence reported a significant overlapping, in terms of clinical symptoms, epidemiology and treatment response, between the two major psychotic disorders—Schizophrenia (SCZ) and Bipolar Disorder (BD). Nevertheless, the shared neurobiological correlates of these two disorders are far from conclusive. This study aims toward a better understanding of possible common microstructural brain alterations in SCZ and BD. Magnetic Resonance Diffusion data of 33 patients with BD, 19 with SCZ and 35 healthy controls were acquired. Diffusion indexes were calculated, then analyzed using Tract-Based Spatial Statistics (TBSS). We tested correlations with clinical and psychological variables. In both patient groups mean diffusion (MD), volume ratio (VR) and radial diffusivity (RD) showed a significant increase, while fractional anisotropy (FA) and mode (MO) decreased compared to the healthy group. Changes in diffusion were located, for both diseases, in the fronto-temporal and callosal networks. Finally, no significant differences were identified between patient groups, and a significant correlations between length of disease and FA and VR within the corpus callosum, corona radiata and thalamic radiation were observed in bipolar disorder. To our knowledge, this is the first study applying TBSS on all the DTI indexes at the same time in both patient groups showing that they share similar impairments in microstructural connectivity, with particular regards to fronto-temporal and callosal communication, which are likely to worsen over time. Such features may represent neural common underpinnings characterizing major psychoses and confirm the central role of white matter pathology in schizophrenia and bipolar disorder.

Psychotic-Like Experiences at the Healthy End of the Psychosis Continuum

There is increasing evidence pointing toward a continuous distribution of psychotic symptoms and accompanying factors between subclinical and clinical populations. However, for the construction of continuum models, a more detailed knowledge of different types of psychotic-like experiences (PLE) and their associations with distress, functional impairment, and demographic variables is needed. We investigated PLE in a sample of healthy adults (N = 206) incorporating the recently developed revised Exceptional Experiences Questionnaire (PAGE-R). For the first time, the PAGE-R was cross validated with PLE, disorganized-, and negative-like symptoms [Schizotypal Personality Questionnaire (SPQ), Physical Anhedonia Scale (PAS)]. We subjected the PAGE-R to exploratory factor analyses and examined the resulting subtypes of EE for specific associations with contextual factors, valence ratings, socio-demographic variables, and general psychological burden (Revised Symptom-Checklist-90). Correlational cross-validation suggested that the PAGE-R measures facets of PLE. Importantly, we (1) identified three types of exceptional experiences (EE): Odd beliefs, dissociative anomalous perceptions, and hallucinatory anomalous perceptions. Further, the results suggested that even in healthy individuals (2) PLE and EE are indicative of reduced functioning, as reflected by increased psychological burden and lower educational achievement. Moreover, (3) similar sex-differences might exist as in psychotic patients with women reporting more positive-like symptoms and EE but less disorganized-like symptoms than men. Importantly, (4) EE might be differentially implicated in psychological functioning. We suggest that the PAGE-R holds the potential to complement the current assessment of sub-clinical psychosis. However, whereas our results might point toward a continuity of psychotic symptoms with EE and normal experiences, they require replication in larger samples as well as equivalence testing across the psychosis continuum. Future analyses incorporating the PAGE-R might shed more light onto mechanisms that are implicated in the progress or resilience toward clinical illness.

Shared white-matter dysconnectivity in schizophrenia and bipolar disorder with psychosis

BACKGROUND

There is an appreciable overlap in the clinical presentation, epidemiology and treatment response of the two major psychotic disorders - schizophrenia and bipolar disorder. Nevertheless, the shared neurobiological correlates of these two disorders are still elusive. Using diffusion tensor imaging (DTI), we sought to identify brain regions which share altered white-matter connectivity across a clinical spectrum of psychotic disorders.

METHOD

A sample of 41 healthy controls, 62 patients in a clinically stable state of an established psychotic disorder (40 with schizophrenia, 22 with bipolar disorder) were studied using DTI. Tract-based spatial statistics (TBSS) was used in order to study group differences between patients with psychosis and healthy controls using fractional anisotropy (FA). Probabilistic tractography was used in order to visualize the clusters that showed significant differences between these two groups.

RESULTS

The TBSS analysis revealed five clusters (callosal, posterior thalamic/optic, paralimbic, fronto-occipital) with reduced FA in psychosis. This reduction in FA was associated with an increase in radial diffusivity and a decrease in mode of anisotropy. Factor analysis revealed a single white-matter integrity factor that predicted social and occupational functioning scores in patients irrespective of the diagnostic categorization.

CONCLUSIONS

Our results show that a shared white-matter dysconnectivity links the two major psychotic disorders. These microstructural abnormalities predict functional outcome better than symptom-based diagnostic boundaries during a clinically stable phase of illness, highlighting the importance of seeking shared neurobiological factors that underlie the clinical spectrum of psychosis.

Fractional anisotropy in individuals with schizophrenia and their nonpsychotic siblings

Fractional anisotropy (FA) was examined in a priori selected fiber tracts in individuals with schizophrenia (n=25) and their non-psychotic siblings (n=29) versus controls (n=35). FA was reduced in a portion of the fornix in individuals with schizophrenia (although this did not survive correction for the number of tracts investigated). FA in the siblings did not differ from that in controls in any of the investigated tracts.

[Schizophrenia and other psychotic disorders in DSM-5: summary of the changes compared to DSM-IV]

With the introduction of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) numerous changes in the area of the schizophrenia spectrum and psychotic disorders have been implemented. Establishing a metastructure based on the characteristics of the spectrum of psychopathological disturbances should improve clarity. The classical subtypes of schizophrenia were eliminated and specific psychopathological dimensions for the assessment of disease severity were added. The special role of Schneiderian first rank symptoms was abandoned and a higher delineation towards schizoaffective disorders is made. The nosological status of catatonia is clarified and occurs together with a consistent use of catatonic disturbances over all chapters. The attenuated psychosis syndrome is added as a new condition for further study. The shared psychotic disorder in the sense of a folie à deux is no longer maintained. However, the initial goal to integrate more disorder-specific etiopathogenetic information into the reconceptualization could not be achieved. Contemporaneously to the development process of DSM-5 the National Institute of Mental Health (NIMH) carried out the research domain criteria project (RDoC) attempting to incorporate the current growth in knowledge of genetics, neurocognitive and cognitive sciences in future diagnostic systems. This article gives an overview of the changes that have been made within the revision process from DSM-IV to DSM-5.

What are the similarities and differences between schizophrenia and schizophrenia-like psychosis of epilepsy? A neuropathological approach to the understanding of schizophrenia spectrum and epilepsy

Temporal lobe epilepsy (TLE) and psychosis coexist more frequently than chance would predict. In this short review, clinical and neuropathological findings of schizophrenia, TLE, and psychosis of epilepsy are described to enhance our understanding of the noncoincidental association between these conditions. In addition, psychosis of epilepsy was included for the first time in the Diagnostic and Statistical Manual of Mental Disorders (DSM), in the recently launched 5th edition, and improvement in diagnostic criteria was highlighted. Since the hippocampus has long been considered an anatomical area involved in the pathophysiology of TLE and schizophrenia, neuropathological studies of psychoses of epilepsy may contribute to our understanding of the pathophysiology of psychosis in general. The discovery of shared mechanisms and/or affected neurochemicals in TLE and schizophrenia might disclose important clues on the vulnerability of patients with TLE to psychotic symptoms and be an opportunity for new treatment development.

Pheno-phenotypes: a holistic approach to the psychopathology of schizophrenia

PURPOSE OF REVIEW

Mental disorders are mainly characterized via symptom assessment. Symptoms are state-like macroscopic anomalies of behaviour, experience, and expression that are deemed relevant for diagnostic purposes. An alternative approach is based on the concept of endophenotypes, which are physiological or behavioural measures occupying the terrain between symptoms and risk genotypes. We will critically discuss these two approaches, and later focus on the concept of pheno-phenotype as it is revealed by recent phenomenological research on schizophrenia.

RECENT FINDINGS

Several studies have been recently published on the schizophrenic pheno-phenotype mainly addressing self-disorders, as well as disorders of time and bodily experience.

SUMMARY

The mainstream approach to psychopathological phenotypes is focussed on easy-to-assess operationalizable symptoms. Thinness of phenotypes and simplification of clinical constructs are the consequences of this. Also, this approach has not been successful in investigating the biological causes of mental disorders. An integrative approach is based on the concept of 'endophenotype'. Endophenotypes were conceptualized as a supportive tool for the genetic dissection of psychiatric disorders. The underlying rationale states that disease-specific phenotypes should be the upstream phenotypic manifestation of a smaller genotype than the whole disease-related genotype. Psychopathological phenotypes can also be characterized in terms of pheno-phenotypes. This approach aims at delineating the manifold phenomena experienced by patients in all of their concrete and distinctive features, so that the features of a pathological condition emerge, while preserving their peculiar feel, meaning, and value for the patient. Systematic explorations of anomalies in the patients' experience, for example, of time, space, body, self, and otherness, may provide a useful integration to the symptom-based and endophenotype-based approaches. These abnormal phenomena can be used as pointers to the fundamental alterations of the structure of subjectivity characterizing each mental disorder.

Future in psychopathology research

Psychopathology research has focused either on the analysis of the mental state in the here and now or on the synthesis of mental status abnormalities with biological markers and outcome data. These two schools of psychopathology, the analytic and the synthetic, make contrasting assumptions, take different approaches, and pursue divergent goals. Analytic psychopathology favors the individual person and unique biography, whereas synthetic psychopathology abstracts from the single case and generalizes to the population level. The dimension of time, especially the prediction of future outcomes, is viewed differently by these two schools. Here I outline how Carpenter's proposal of strong inference and theory testing in psychopathology research can be used to test the value of analytic and synthetic psychopathology. The emerging field of personalized psychiatry can clarify the relevance of psychopathology for contemporary research in psychiatry.

Structure of the psychotic disorders classification in DSM-5

Schizophrenia spectrum disorders attract great interest among clinicians, researchers, and the lay public. While the diagnostic features of schizophrenia have remained unchanged for more than 100 years, the mechanism of illness has remained elusive. There is increasing evidence that the categorical diagnosis of schizophrenia and other psychotic disorders contributes to this lack of progress. The 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) continues the categorical classification of psychiatric disorders since the research needed to establish a new nosology of equal or greater validity is lacking. However, even within a categorical system, the DSM-5 aims to capture the underlying dimensional structure of psychosis. The domains of psychopathology that define psychotic disorders are presented not simply as features of schizophrenia. The level, the number, and the duration of psychotic signs and symptoms are used to demarcate psychotic disorders from each other. Finally, the categorical assessment is complemented with a dimensional assessment of psychosis that allows for more specific and individualized assessment of patients. The structure of psychosis as outlined in the DSM-5 may serve as a stepping-stone towards a more valid classification system, as we await new data to redefine psychotic disorders.

Is aberrant functional connectivity a psychosis endophenotype? A resting state functional magnetic resonance imaging study

BACKGROUND

Schizophrenia and bipolar disorder share overlapping symptoms and risk genes. Shared aberrant functional connectivity is hypothesized in both disorders and in relatives.

METHODS

We investigated resting state functional magnetic resonance imaging in 70 schizophrenia and 64 psychotic bipolar probands, their respective first-degree relatives (n = 70 and 52), and 118 healthy subjects. We used independent component analysis to identify components representing various resting state networks and assessed spatial aspects of functional connectivity within all networks. We first investigated group differences using five-level, one-way analysis of covariance (ANCOVA), followed by post hoc t tests within regions displaying ANCOVA group differences and correlation of such functional connectivity measures with symptom ratings to examine clinical relationships.

RESULTS

Seven networks revealed abnormalities (five-level one-way ANCOVA, family-wise error correction p < .05): A) fronto-occipital, B) midbrain/cerebellum, C) frontal/thalamic/basal ganglia, D) meso/paralimbic, E) posterior default mode network, F) fronto-temporal/paralimbic and G) sensorimotor networks. Abnormalities in networks B and F were unique to schizophrenia probands. Furthermore, abnormalities in networks D and E were common to both patient groups. Finally, networks A, C, and G showed abnormalities shared by probands and their relative groups. Negative correlation with Positive and Negative Syndrome Scale negative and positive scores were found in regions within network C and F respectively, and positive correlation with Positive and Negative Syndrome Scale negative scores was found in regions in network D among schizophrenia probands only.

CONCLUSIONS

Schizophrenia, psychotic bipolar probands, and their relatives share both unique and overlapping within-network brain connectivity abnormalities, revealing potential psychosis endophenotypes.

Auditory hallucinations in a cross-diagnostic sample of psychotic disorder patients: a descriptive, cross-sectional study

BACKGROUND

Auditory hallucinations (AH) are a cardinal feature of schizophrenia spectrum disorders. They are not disease specific, however, and can occur in other conditions, including affective psychoses.

METHODS

In this descriptive, cross-sectional study, we examined AH in relation to other psychotic symptoms, mood symptoms, illness severity, and functional status in 569 patients with psychosis (n = 172 schizophrenia, n = 153 schizoaffective disorder, n = 244 bipolar disorder with psychotic features).

RESULTS

A total of 323 (56.7%) patients reported a lifetime history of AH (75.6% of patients with schizophrenia, 71.9% schizoaffective disorder, and 34.0% bipolar disorder). The mean score for the hallucinations item (P3) of the Positive and Negative Syndrome Scale in the AH group was 3.66 ± 1.79, indicating mild to moderate state hallucinations severity. Auditory hallucinations were strongly associated with hallucinations in other sensory modalities and with the first-rank symptoms of delusions of control, thought insertion, and thought broadcasting. Multivariate analysis showed that AH were associated with lower education even after controlling for diagnosis, age, and sex. There was no association between AH and functional status as measured by the Multnomah Community Ability Scale.

CONCLUSIONS

Auditory hallucinations are associated with specific clinical features across the continuum of both schizophrenic and affective psychoses independent of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, diagnosis.

Neurometabolites in schizophrenia and bipolar disorder - a systematic review and meta-analysis

This meta-analysis evaluates alterations of neurometabolites in schizophrenia and bipolar disorder. PubMed was searched to find controlled studies evaluating N-acetylaspartate (NAA), Choline (Cho) and Creatine (Cr) assessed with ((1))H-MRS (proton magnetic resonance spectroscopy) in patients with schizophrenia and bipolar disorder up to September 2010. Random effects meta-analyses were conducted to estimate pooled standardized mean differences. The statistic was used to quantify inconsistencies. Subgroup analyses were conducted to explore potential explanations for inconsistencies. The systematic review included 146 studies with 5643 participants. NAA levels were affected in schizophrenia and bipolar disorder. Decreased levels in the basal ganglia and frontal lobe were the most consistent findings in schizophrenia; decreased levels in the basal ganglia were the most consistent findings in bipolar disorder. Cho and Cr levels were not altered in either disorder. Findings for Cr were most consistent in the thalamus, frontal lobe and dorsolateral prefrontal cortex in schizophrenia and the basal ganglia and frontal lobe in bipolar disorder. Findings for Cho were most consistent in the thalamus, frontal lobe and anterior cingulate cortex in schizophrenia and basal ganglia in bipolar disorder. Large, carefully designed studies are needed to better estimate the extent of alterations in neurometabolites.

Bleuler and the neurobiology of schizophrenia

Schizophrenia remains a major challenge for psychiatry. One hundred years after the publication of Eugen Bleuler's monograph, we are still debating the nosology and mechanisms of schizophrenia. We have stalled in the development of more effective treatments, after success with the introduction of antipsychotic medication. Cure and prevention remain in the distance. This article reviews the importance of Bleuler's monograph for the neuroscientific exploration of schizophrenia. While Bleuler assumed that schizophrenia has a neural basis, he remained agnostic on possible mechanisms and skeptical about the value of pathological diagnosis. He preferred psychological understanding over neural explanation. He gave hope by making schizophrenia dimensional and less predictive of course and outcome. To make progress now, we need to redefine schizophrenia at the level of the brain.

Are screening instruments valid for psychotic-like experiences? A validation study of screening questions for psychotic-like experiences using in-depth clinical interview

Individuals who report psychotic-like experiences are at increased risk of future clinical psychotic disorder. They constitute a unique "high-risk" group for studying the developmental trajectory to schizophrenia and related illnesses. Previous research has used screening instruments to identify this high-risk group, but the validity of these instruments has not yet been established. We administered a screening questionnaire with 7 items designed to assess psychotic-like experiences to 334 adolescents aged 11-13 years. Detailed clinical interviews were subsequently carried out with a sample of these adolescents. We calculated sensitivity and specificity and positive predictive value (PPV) and negative predictive value (NPV) for each screening question for the specific symptom it enquired about and also in relation to any psychotic-like experience. The predictive power varied substantially between items, with the question on auditory hallucinations ("Have you ever heard voices or sounds that no one else can hear?") providing the best predictive power. For interview-verified auditory hallucinations specifically, this question had a PPV of 71.4% and an NPV of 90.4%. When assessed for its predictive power for any psychotic-like experience (including, but not limited to, auditory hallucinations), it provided a PPV of 100% and an NPV of 88.4%. Two further questions-relating to visual hallucinations and paranoid thoughts-also demonstrated good predictive power for psychotic-like experiences. Our results suggest that it may be possible to screen the general adolescent population for psychotic-like experiences with a high degree of accuracy using a short self-report questionnaire.

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

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Memoir and the Diagnosis of Schizophrenia: Reflections on The Center Cannot Hold, Me, Myself, and Them, and the 'Crumbling Twin Pillars' of Kraepelinian Psychiatry

In 1896 Emil Kraepelin revolutionised the classification of psychosis by identifying what he argued were two natural disease entities: manic-depressive psychosis (bipolar disorder) and dementia praecox (schizophrenia). Kraepelin's twin pillars have governed psychiatric thinking, practice and research for over a century. However, a growing number of researchers, clinicians, and mental health service users argue contest the claim that there are fundamental differences between schizophrenia and bipolar disorder, and call for a symptom-led approach which prioritises subjective experience over diagnostic category. How can the published first-person accounts of experts by experience contribute to this debate? This short paper looks at the representation of psychiatric diagnosis in two much-lauded autobiographies: Kurt Snyder's Me, Myself, and Them: A Firsthand Account of One Young Person's Experience with Schizophrenia (2007) and Elyn Saks' The Center Cannot Hold: My Journey Through Madness (2007). As well as providing a prognosis and a plan for treatment, the psychiatric diagnosis of schizophrenia, for both these writers, gives shape and meaning to the illness experience and ultimately becomes the pivot or platform from which identity and memoir unfold. Saks and Snyder do not claim to speak for all people who receive a diagnosis of schizophrenia and it would be a mistake to read their texts in this way even if they did. But if the debate about the future of psychiatric nosology is going to respect subjective experience, the insights they and others offer in to the multiple meanings and effects of psychiatric diagnosis more than compel our attention.

Hippocampal interneurons in bipolar disorder

CONTEXT

Postmortem studies have reported decreased density and decreased gene expression of hippocampal interneurons in bipolar disorder, but neuroimaging studies of hippocampal volume and function have been inconclusive.

OBJECTIVE

To assess hippocampal volume, neuron number, and interneurons in the same specimens of subjects with bipolar disorder and healthy control subjects.

DESIGN

Whole human hippocampi of 14 subjects with bipolar disorder and 18 healthy control subjects were cut at 2.5-mm intervals and sections from each tissue block were either Nissl-stained or stained with antibodies against somatostatin or parvalbumin. Messenger RNA was extracted from fixed tissue and real-time quantitative polymerase chain reaction was performed.

SETTING

Basic research laboratories at Vanderbilt University and McLean Hospital.

SAMPLES

Brain specimens from the Harvard Brain Tissue Resource Center at McLean Hospital.

MAIN OUTCOME MEASURES

Volume of pyramidal and nonpyramidal cell layers, overall neuron number and size, number of somatostatin- and parvalbumin-positive interneurons, and messenger RNA levels of somatostatin, parvalbumin, and glutamic acid decarboxylase 1.

RESULTS

The 2 groups did not differ in the total number of hippocampal neurons, but the bipolar disorder group showed reduced volume of the nonpyramidal cell layers, reduced somal volume in cornu ammonis sector 2/3, reduced number of somatostatin- and parvalbumin-positive neurons, and reduced messenger RNA levels for somatostatin, parvalbumin, and glutamic acid decarboxylase 1.

CONCLUSION

Our results indicate a specific alteration of hippocampal interneurons in bipolar disorder, likely resulting in hippocampal dysfunction.

Are Bipolar Disorder and Schizophrenia Neuroanatomically Distinct? An Anatomical Likelihood Meta-analysis

Objective: There is renewed debate on whether modern diagnostic classification should adopt a dichotomous or dimensional approach to schizophrenia and bipolar disorder. This study synthesizes data from voxel-based studies of schizophrenia and bipolar disorder to estimate the extent to which these conditions have a common neuroanatomical phenotype. Methods: A post-hoc meta-analytic estimation of the extent to which bipolar disorder, schizophrenia, or both conditions contribute to brain gray matter differences compared to controls was achieved using a novel application of the conventional anatomical likelihood estimation (ALE) method. 19 schizophrenia studies (651 patients and 693 controls) were matched as closely as possible to 19 bipolar studies (540 patients and 745 controls). Result: Substantial overlaps in the regions affected by schizophrenia and bipolar disorder included regions in prefrontal cortex, thalamus, left caudate, left medial temporal lobe, and right insula. Bipolar disorder and schizophrenia jointly contributed to clusters in the right hemisphere, but schizophrenia was almost exclusively associated with additional gray matter deficits (left insula and amygdala) in the left hemisphere. Limitation: The current meta-analytic method has a number of constraints. Importantly, only studies identifying differences between controls and patient groups could be included in this analysis. Conclusion: Bipolar disorder shares many of the same brain regions as schizophrenia. However, relative to neurotypical controls, lower gray matter volume in schizophrenia is more extensive and includes the amygdala. This fresh application of ALE accommodates multiple studies in a relatively unbiased comparison. Common biological mechanisms may explain the neuroanatomical overlap between these major disorders, but explaining why brain differences are more extensive in schizophrenia remains challenging.