A developmental model for similarities and dissimilarities between schizophrenia and bipolar disorder

Differentiating patterns of amygdala-frontal functional connectivity in schizophrenia and bipolar disorder

BACKGROUND

Insight into the neural mechanisms underlying the shared and disparate features of schizophrenia (SZ) and bipolar disorder (BD) is limited. The amygdala and prefrontal cortex (PFC) appear to have crucial roles in SZ and BD, yet abnormalities appear to manifest differently in the 2 disorders.

METHODS

Eighteen participants with SZ, 18 participants with BD, and 18 healthy controls (HC) underwent resting-state functional magnetic resonance imaging. Resting-state functional connectivity (rsFC) between the PFC and the amygdala divided into 3 subregions (the laterobasal, centromedial, and superficial amygdala) was examined using probabilistic anatomic maps. For each participant, rsFC maps of the 3 amygdala subregions were computed and compared across the 3 groups.

RESULTS

Compared with the HC group, we found significant differences in rsFC between the amygdala and PFC in the SZ and BD groups. In direct comparison between the SZ and BD groups, distinct patterns of rsFC between the amygdala and PFC were observed, particularly in the superficial amygdala. RsFC between the amygdala and the dorsal lateral PFC was significantly decreased in the SZ group, whereas rsFC between the amygdyala and the ventral PFC was significantly decreased in the BD group.

CONCLUSIONS

These results strongly suggest dorsal vs ventral PFC differentiation in amygdala-PFC neural system abnormalities between SZ and BD. These regional differences in SZ and BD may give rise to the differences in clinical characteristics observed in SZ and BD, and may implicate potential avenues for differentiating the 2 disorders during early stages of illness.

A comparative diffusion tensor imaging study of corpus callosum subregion integrity in bipolar disorder and schizophrenia

Structural magnetic resonance imaging (MRI) studies have provided evidence for corpus callosum (CC) white matter abnormalities in bipolar disorder (BD) and schizophrenia (SZ). These findings include alterations in shape, volume, white matter intensity and structural integrity compared to healthy control populations. Although CC alterations are implicated in both SZ and BD, no study of which we are aware has investigated callosal subregion differences between these two patient populations. We used diffusion tensor imaging (DTI) to assess CC integrity in patients with BD (n=16), SZ (n=19) and healthy controls (HC) (n=24). Fractional anisotropy (FA) of CC subregions was measured using region of interest (ROI) analysis and compared in the three groups. Significant group differences of FA values were revealed in five CC subregions, including the anterior genu, middle genu, posterior genu, posterior body and anterior splenium. FA values of the same subregions were significantly reduced in patients with SZ compared with HC. FA values were also significantly reduced in patients with BD compared to the HC group in the same subregions, excepting the middle genu. No significant difference was found between patient groups in any region. Most of the alterations in CC subregions were present in both the BD and SZ groups. These results imply an overlap in potential pathology, possibly relating to risk factors common to both disorders. The one region that differed between patient groups, the middle genu area, may serve as an illness marker and is perhaps involved in the different cognitive impairments observed in BD and SZ.

How might ZNF804A variants influence risk for schizophrenia and bipolar disorder? A literature review, synthesis, and bioinformatic analysis

The gene that encodes zinc finger protein 804A (ZNF804A) became a candidate risk gene for schizophrenia (SZ) after surpassing genome-wide significance thresholds in replicated genome-wide association scans and meta-analyses. Much remains unknown about this reported gene expression regulator; however, preliminary work has yielded insights into functional and biological effects of ZNF804A by targeting its regulatory activities in vitro and by characterizing allele-specific interactions with its risk-conferring single nucleotide polymorphisms (SNPs). There is now strong epidemiologic evidence for a role of ZNF804A polymorphisms in both SZ and bipolar disorder (BD); however, functional links between implicated variants and susceptible biological states have not been solidified. Here we briefly review the genetic evidence implicating ZNF804A polymorphisms as genetic risk factors for both SZ and BD, and discuss the potential functional consequences of these variants on the regulation of ZNF804A and its downstream targets. Empirical work and predictive bioinformatic analyses of the alternate alleles of the two most strongly implicated ZNF804A polymorphisms suggest they might alter the affinity of the gene sequence for DNA- and/or RNA-binding proteins, which might in turn alter expression levels of the gene or particular ZNF804A isoforms. Future work should focus on clarifying the critical periods and cofactors regulating these genetic influences on ZNF804A expression, as well as the downstream biological consequences of an imbalance in the expression of ZNF804A and its various mRNA isoforms.

Association between symptom dimensions and categorical diagnoses of psychosis: a cross-sectional and longitudinal investigation

CONTEXT

Cross-sectional studies of the signs and symptoms of psychosis yield dimensional phenotypes. However, the validity and clinical utility of such dimensions remain debated. This study investigated the structure of psychotic symptomatology, the stability of the structure over time, and the concordance between symptom dimensions and categorical diagnoses.

METHODS

Sample consisted of 500 first-episode psychotic patients. A cross-sectional study (N = 500) investigated the organizational structure of symptom dimensions at the onset of psychosis and its concordance with categorical diagnoses; next, a nested longitudinal study (N = 100) examined the stability of the symptom dimensions structure after 5-10 years of follow-up.

RESULTS

Factor analyses identified 6 first-order factors (mania, negative, disorganization, depression, hallucinations, and delusions) and 2 high-order factors (affective and nonaffective psychoses). Cumulative variance accounted for by the first and high-order factors was 63%: 31% by the first-order factors and 32% by the high-order factors. The factorial structure of psychotic symptoms during first episode remained stable after 5-10 years of follow-up. The overall concordance between 4 categorical diagnostic groups (schizophrenia, mania with psychosis, psychotic depression and schizoaffective disorder) and dimensional symptom ranged from 62.2% to 73.1% (when the schizoaffective group was excluded).

CONCLUSIONS

Symptoms of psychosis assume a multidimensional hierarchical structure. This hierarchical model was stable over time and showed good concordance with categorical diagnoses. The combined use of dimensional and categorical approach to psychotic disorders would be of clinical and research utility.

Dysfunction and Dysconnection in Cortical-Striatal Networks during Sustained Attention: Genetic Risk for Schizophrenia or Bipolar Disorder and its Impact on Brain Network Function

Abnormalities in the brain's attention network may represent early identifiable neurobiological impairments in individuals at increased risk for schizophrenia or bipolar disorder. Here, we provide evidence of dysfunctional regional and network function in adolescents at higher genetic risk for schizophrenia or bipolar disorder [henceforth higher risk (HGR)]. During fMRI, participants engaged in a sustained attention task with variable demands. The task alternated between attention (120 s), visual control (passive viewing; 120 s), and rest (20 s) epochs. Low and high demand attention conditions were created using the rapid presentation of two- or three-digit numbers. Subjects were required to detect repeated presentation of numbers. We demonstrate that the recruitment of cortical and striatal regions are disordered in HGR: relative to typical controls (TC), HGR showed lower recruitment of the dorsal prefrontal cortex, but higher recruitment of the superior parietal cortex. This imbalance was more dramatic in the basal ganglia. There, a group by task demand interaction was observed, such that increased attention demand led to increased engagement in TC, but disengagement in HGR. These activation studies were complemented by network analyses using dynamic causal modeling. Competing model architectures were assessed across a network of cortical-striatal regions, distinguished at a second level using random-effects Bayesian model selection. In the winning architecture, HGR were characterized by significant reductions in coupling across both frontal-striatal and frontal-parietal pathways. The effective connectivity analyses indicate emergent network dysconnection, consistent with findings in patients with schizophrenia. Emergent patterns of regional dysfunction and dysconnection in cortical-striatal pathways may provide functional biological signatures in the adolescent risk-state for psychiatric illness.

Role of immunological factors in the pathophysiology and diagnosis of bipolar disorder: comparison with schizophrenia

Several lines of evidence point to the key role of neurobiological mechanisms and shared genetic background in schizophrenia and bipolar disorder. For both disorders, neurodevelopmental and neurodegenerative processes have been postulated to be relevant for the pathogenesis as well as dysregulation of immuno-inflammatory pathways. Inflammation is a complex biological response to harmful stimuli and it is mediated by cytokines cascades, cellular immune responses, oxidative factors and hormone regulation. Cytokines, in particular, are supposed to play a critical role in infectious and inflammatory processes, mediating the cross-talk between the brain and the immune system; they also possibly contribute to the development of the central nervous system. From this perspective, even though mixed results have been reported, it seems that both schizophrenia and bipolar disorder are associated with an imbalance in inflammatory cytokines; in fact, some of these could represent biological markers of illness and could be possible targets for pharmacological treatments. In light of these considerations, the purpose of the present paper was to provide a comprehensive and critical review of the existing literature about immunological abnormalities in bipolar disorder with particular attention to the similarities and differences with schizophrenia.

Excess early mortality in schizophrenia

Schizophrenia is often referred to as one of the most severe mental disorders, primarily because of the very high mortality rates of those with the disorder. This article reviews the literature on excess early mortality in persons with schizophrenia and suggests reasons for the high mortality as well as possible ways to reduce it. Persons with schizophrenia have an exceptionally short life expectancy. High mortality is found in all age groups, resulting in a life expectancy of approximately 20 years below that of the general population. Evidence suggests that persons with schizophrenia may not have seen the same improvement in life expectancy as the general population during the past decades. Thus, the mortality gap not only persists but may actually have increased. The most urgent research agenda concerns primary candidates for modifiable risk factors contributing to this excess mortality, i.e., side effects of treatment and lifestyle factors, as well as sufficient prevention and treatment of physical comorbidity.

Reduced burden of very large and rare CNVs in bipolar affective disorder

OBJECTIVES

Large, rare chromosomal copy number variants (CNVs) have been shown to increase the risk for schizophrenia and other neuropsychiatric disorders including autism, attention-deficit hyperactivity disorder, learning difficulties, and epilepsy. Their role in bipolar disorder (BD) is less clear. There are no reports of an increase in large, rare CNVs in BD in general, but some have reported an increase in early-onset cases. We previously found that the rate of such CNVs in individuals with BD was not increased, even in early-onset cases. Our aim here was to examine the rate of large rare CNVs in BD in comparison with a new large independent reference sample from the same country.

METHODS

We studied the CNVs in a case-control sample consisting of 1,650 BD cases (reported previously) and 10,259 reference individuals without a known psychiatric disorder who took part in the original Wellcome Trust Case Control Consortium (WTCCC) study. The 10,259 reference individuals were affected with six non-psychiatric disorders (coronary artery disease, types 1 and 2 diabetes, hypertension, Crohn's disease, and rheumatoid arthritis). Affymetrix 500K array genotyping data were used to call the CNVs.

RESULTS

The rate of CNVs > 100 kb was not statistically different between cases and controls. The rate of very large (defined as > 1 Mb) and rare (< 1%) CNVs was significantly lower in patients with BD compared with the reference group. CNV loci associated with schizophrenia were not enriched in BD and, in fact, cases of BD had the lowest number of such CNVs compared with any of the WTCCC cohorts; this finding held even for the early-onset BD cases.

CONCLUSIONS

Schizophrenia and BD differ with respect to CNV burden and association with specific CNVs. Our findings support the hypothesis that BD is etiologically distinct from schizophrenia with respect to large, rare CNVs and the accompanying associated neurodevelopmental abnormalities.

Can P300 distinguish among schizophrenia, schizoaffective and bipolar I disorders? An ERP study of response inhibition

Research utilizing visual event-related brain potentials (ERPs) has demonstrated that reduced P300 amplitude and prolonged latency may qualify as a biological marker (biomarker) for schizophrenia (SZ). We examined P300 characteristics in response inhibition among three putatively distinct psychopathology groups including schizophrenia (SZ), bipolar I disorder (BD) and schizoaffective disorder (SA) in comparison with healthy controls (CT) to determine their electrophysiological distinctiveness. In two separate studies, deficits in response inhibition indexed by the P300 component were investigated using a lateralized Go/NoGo task. We hypothesized that deficits in response inhibition would be present and distinctive among the groups. In both studies, SZ showed response inhibition deficits as measured by P300 when stimuli were presented to the right visual field. In Study 2, delayed cognitive stimulus evaluation was observed in BD as indexed by prolonged P300 latency for NoGo trials. Six selected NoGo P300 variables out of thirty six NoGo P300 variables (18 amplitude, 18 latency) correctly classified SZ (79%), SA (64%) in Study 1 and seven variables selected in Study 2 classified CT (80%), and SZ (61%), BD (67%) and CT (68%) with the accuracy higher than chance level (33%). The findings suggest that distinct P300 features in response inhibition may be biomarkers with the capacity to distinguish BD and SZ, although SA was not clearly distinguishable from SZ and CT.

Disturbances in reality testing as markers of risk in offspring of parents with bipolar disorder: a systematic review from a developmental psychopathology perspective

OBJECTIVES

This comprehensive review examined the prevalence and progression of disturbances in reality testing (DRT), defined as psychotic symptoms, cognitive disruptions, and thought problems, in offspring of parents with bipolar disorder (O-BD). Our approach was grounded in a developmental psychopathology perspective and considered a broader phenotype of risk within the bipolar-schizophrenia spectrum as measured by categorical and dimensional assessments of DRT in high-risk youth.

METHODS

Relevant studies were identified from numerous sources (e.g., PubMed, reference sections, and colleagues). Inclusion criteria were: (i) family risk studies published between 1975 and 2012 in which O-BD were contrasted with a comparison group (e.g., offspring of parents who had other psychiatric disorders or were healthy) on DRT outcomes and (ii) results reported for categorical or dimensional assessments of DRT (e.g., schizophrenia, psychotic symptoms, cluster A personality traits, or thought problems), yielding a total of 23 studies.

RESULTS

Three key findings emerged: (i) categorical approaches of DRT in O-BD produced low incidence base rates and almost no evidence of significant differences in DRT between O-BD and comparison groups, whereas (ii) many studies using dimensional assessments of DRT yielded significant group differences in DRT. Furthermore, (iii) preliminary evidence from dimensional measures suggested that the developmental progression of DRT in O-BD might represent a prodrome of severe psychological impairment.

CONCLUSIONS

Preliminary but promising evidence suggests that DRT is a probable marker of risk for future impairment in O-BD. Methodological strengths and weaknesses, the psychometric properties of primary DRT constructs, and future directions for developmental and longitudinal research with O-BD are discussed.

A review of neuroimaging studies of young relatives of individuals with schizophrenia: a developmental perspective from schizotaxia to schizophrenia

In an effort to identify the developing abnormalities preceding psychosis, Dr. Ming T. Tsuang and colleagues at Harvard expanded Meehl's concept of "schizotaxia," and examined brain structure and function in families affected by schizophrenia (SZ). Here, we systematically review genetic (familial) high-risk (HR) studies of SZ using magnetic resonance imaging (MRI), examine how findings inform models of SZ etiology, and suggest directions for future research. Neuroimaging studies of youth at HR for SZ through the age of 30 were identified through a MEDLINE (PubMed) search. There is substantial evidence of gray matter volume abnormalities in youth at HR compared to controls, with an accelerated volume reduction over time in association with symptoms and cognitive deficits. In structural neuroimaging studies, prefrontal cortex (PFC) alterations were the most consistently reported finding in HR. There was also consistent evidence of smaller hippocampal volume. In functional studies, hyperactivity of the right PFC during performance of diverse tasks with common executive demands was consistently reported. The only longitudinal fMRI study to date revealed increasing left middle temporal activity in association with the emergence of psychotic symptoms. There was preliminary evidence of cerebellar and default mode network alterations in association with symptoms. Brain abnormalities in structure, function and neurochemistry are observed in the premorbid period in youth at HR for SZ. Future research should focus on the genetic and environmental contributions to these alterations, determine how early they emerge, and determine whether they can be partially or fully remediated by innovative treatments.

Genome-wide association study of atypical psychosis

Atypical psychosis with a periodic course of exacerbation and features of major psychiatric disorders [schizophrenia (SZ) and bipolar disorder (BD)] has a long history in clinical psychiatry in Japan. Based upon the new criteria of atypical psychosis, a Genome-Wide Association Study (GWAS) was conducted to identify the risk gene or variants. The relationships between atypical psychosis, SZ and BD were then assessed using independent GWAS data. Forty-seven patients with solid criteria of atypical psychosis and 882 normal controls (NCs) were scanned using an Affymetrics 6.0 chip. GWAS SZ data (560 SZ cases and 548 NCs) and GWAS BD (107 cases with BD type 1 and 107 NCs) were compared using gene-based analysis. The most significant SNPs were detected around the CHN2/CPVL genes (rs245914, P = 1.6 × 10(-7)) , COL21A1 gene (rs12196860, P = 2.45 × 10(-7) ), and PYGL/TRIM9 genes (rs1959536, P = 7.73 × 10(-7) ), although none of the single-nucleotide polymorphisms exhibited genome-wide significance (P = 5 × 10(-8) ). One of the highest peaks was detected on the major histocompatibility complex region, where large SZ GWASs have previously disclosed an association. The gene-based analysis suggested significant enrichment between SZ and atypical psychosis (P = 0.01), but not BD. This study provides clues about the types of patient whose diagnosis lies between SZ and BD. Studies with larger samples are required to determine the causal variant.

Attachment and temperament profiles among the offspring of a parent with bipolar disorder

INTRODUCTION

Attachment is associated both with the risk of developing a mood disorder and temperamental profile. Relatively little is known about these associations in children of a parent with bipolar disorder (BD). The present study is a preliminary analysis of the association between attachment, temperament and psychopathology among high-risk offspring.

METHODS

As part of an ongoing prospective cohort study, offspring from families with one parent with BD (HR) and offspring from families with unaffected parents (C) were clinically assessed using KSADS-PL format interviews annually. Validated self-report measures of perceived attachment and temperament were completed.

RESULTS

Perceived attachment did not differentiate HR from C offspring and did not predict psychopathology or mood disorder in particular. However, high emotionality significantly predicted the risk of psychopathology in HR offspring, where 1 standard deviation increase in emotionality significantly increased the hazard of psychopathology by a factor of 1.36 (p=0.0009) and mood disorder by a factor of 1.24 (p=0.02).

LIMITATIONS

Use of retrospective measures and low sample size for some models.

CONCLUSIONS

There may be no gross abnormalities in attachment among HR compared to C offspring. It remains unclear if emotionality is a barometer of illness or a true risk factor in this population. More longitudinal research is needed to advance understanding of the influential pathways by which psychosocial risk factors impact the development of BD. This research has implications for targeted early interventions in HR youth.

A comprehensive review of auditory verbal hallucinations: lifetime prevalence, correlates and mechanisms in healthy and clinical individuals

Over the years, the prevalence of auditory verbal hallucinations (AVHs) have been documented across the lifespan in varied contexts, and with a range of potential long-term outcomes. Initially the emphasis focused on whether AVHs conferred risk for psychosis. However, recent research has identified significant differences in the presentation and outcomes of AVH in patients compared to those in non-clinical populations. For this reason, it has been suggested that auditory hallucinations are an entity by themselves and not necessarily indicative of transition along the psychosis continuum. This review will examine the presentation of auditory hallucinations across the life span, as well as in various clinical groups. The stages described include childhood, adolescence, adult non-clinical populations, hypnagogic/hypnopompic experiences, high schizotypal traits, schizophrenia, substance induced AVH, AVH in epilepsy, and AVH in the elderly. In children, need for care depends upon whether the child associates the voice with negative beliefs, appraisals and other symptoms of psychosis. This theme appears to carry right through to healthy voice hearers in adulthood, in which a negative impact of the voice usually only exists if the individual has negative experiences as a result of their voice(s). This includes features of the voices such as the negative content, frequency, and emotional valence as well as anxiety and depression, independently or caused by voices presence. It seems possible that the mechanisms which maintain AVH in non-clinical populations are different from those which are behind AVH presentations in psychotic illness. For example, the existence of maladaptive coping strategies in patient populations is one significant difference between clinical and non-clinical groups which is associated with a need for care. Whether or not these mechanisms start out the same and have differential trajectories is not yet evidenced. Future research needs to focus on the comparison of underlying factors and mechanisms that lead to the onset of AVH in both patient and non-clinical populations.

Amygdala-hippocampal shape and cortical thickness abnormalities in first-episode schizophrenia and mania

BACKGROUND

Abnormalities in cortical thickness and subcortical structures have been studied in schizophrenia but little is known about corresponding changes in mania and brain structural differences between these two psychiatric conditions, especially early in the stage of the illness. In this study we aimed to compare cortical thickness and shape of the amygdala-hippocampal complex in first-episode schizophrenia (FES) and mania (FEM). Method Structural magnetic resonance imaging (MRI) was performed on 28 FES patients, 28 FEM patients and 28 healthy control subjects who were matched for age, gender and handedness.

RESULTS

Overall, the shape of the amygdala was deformed in both patient groups, relative to controls. Compared to FEM patients, FES patients had significant inward shape deformation in the left hippocampal tail, right hippocampal body and a small region in the right amygdala. Cortical thinning was more widespread in FES patients, with significant differences found in the temporal brain regions when compared with FEM and controls.

CONCLUSIONS

Significant differences were observed between the two groups of patients with FES and FEM in terms of the hippocampal shape and cortical thickness in the temporal region, highlighting that distinguishable brain structural changes are present early in the course of schizophrenia and mania.

Cortical surface complexity in frontal and temporal areas varies across subgroups of schizophrenia

Schizophrenia is assumed to be a neurodevelopmental disorder, which might involve disturbed development of the cerebral cortex, especially in frontal and medial temporal areas. Based on a novel spherical harmonics approach to measuring complexity of cortical folding, we applied a measure based on fractal dimension (FD) to investigate the heterogeneity of regional cortical surface abnormalities across subgroups of schizophrenia defined by symptom profiles. A sample of 87 patients with DSM-IV schizophrenia was divided into three subgroups (based on symptom profiles) with predominantly negative (n = 31), disorganized (n = 23), and paranoid (n = 33) symptoms and each compared to 108 matched healthy controls. While global FD measures were reduced in the right hemisphere of the negative and paranoid subgroups, regional analysis revealed marked heterogeneity of regional FD alterations. The negative subgroup showed most prominent reductions in left anterior cingulate, superior frontal, frontopolar, as well as right superior frontal and superior parietal cortices. The disorganized subgroup showed reductions in bilateral ventrolateral/orbitofrontal cortices, and several increases in the left hemisphere, including inferior parietal, middle temporal, and midcingulate areas. The paranoid subgroup showed only few changes, including decreases in the right superior parietal and left fusiform region, and increase in the left posterior cingulate cortex. Our findings suggest regional heterogeneity of cortical folding complexity, which might be related to biological subgroups of schizophrenia with differing degrees of altered cortical developmental pathology.

Neurological soft signs discriminate schizophrenia from major depression but not bipolar disorder

BACKGROUND

Neurological soft signs (NSS) are minor neurological abnormalities, including motor, sensory, and inhibitory dysfunction. Schizophrenia and other neuropsychiatric disorders are associated with a higher prevalence of NSS. However, the relationships between NSS and schizophrenia, bipolar disorder, and major depression are unclear. The present study aimed to examine the specificity of NSS among these three clinical groups.

METHOD

A total of 120 demographically matched participants (30 each in schizophrenia, bipolar disorder, major depression, and healthy controls) were recruited for the study. NSS subscales of the Cambridge Neurological Inventory (CNI) were administered to each participant.

RESULTS

Significant differences were found in the total score of NSS (p<0.01), and the subscale scores for motor coordination (p<0.01), sensory integration (p=0.01) and disinhibition (p<0.01). Both patients with schizophrenia and bipolar disorder showed more total NSS signs than healthy controls (p<0.01). Patients with schizophrenia also showed more total NSS signs than patients with major depression (p=0.02). Both patients with schizophrenia and patients with bipolar disorder showed more motor coordination signs than healthy controls and patients with major depression (p<0.05). Moreover, compared with healthy controls, patients with schizophrenia showed more disinhibition signs (p<0.01), while patients with bipolar disorder showed more sensory integration signs (p<0.01). Discriminant analysis showed 77.5% of correct classification of patients with schizophrenia and bipolar disorder from patients with major depression and healthy controls.

CONCLUSIONS

NSS are not unique to schizophrenia, but are also found in bipolar disorder, while patients with major depression are comparable to normal controls. Our results suggest that NSS, especially motor-coordination signs, can differentiate schizophrenia from major depression but not bipolar disorder. Our results may provide further evidence to support the similarity between schizophrenia and bipolar disorder from the dimension of behavioral expression.

An Overview of Cognitive Remediation Therapy for People with Severe Mental Illness

Cognitive remediation refers to nonpharmacological methods of improving cognitive function in people with severe mental disorders. Cognitive remediation therapy (CRT) can be delivered via computerised programs, of varying length and complexity, or can be undertaken one-on-one by a trained clinician. There has been a considerable interest in cognitive remediation, driven by recognition that cognitive deficits are a major determinant of outcome in people with severe, chronic mental illnesses. CRT has been shown to be effective, especially if combined with vocational rehabilitation.

High prevalence of childhood trauma in patients with schizophrenia spectrum and affective disorder

OBJECTIVE

Childhood trauma (CT) is a major risk factor for various psychiatric disorders. We wanted to determine the prevalence of CT in a catchment area-based sample of schizophrenia spectrum and affective disorder (including bipolar disorder and depressive episodes with psychotic features) and to explore potential differences in types of CT between the diagnostic groups.

METHOD

Three hundred five patients were recruited consecutively from psychiatric units at 3 major hospitals in Oslo, Norway, diagnosed with Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Traumatic childhood events were assessed with Childhood Trauma Questionnaire.

RESULTS

Eighty-two percent of the patients had experienced one or more CT events, the most frequent subtype of trauma being emotional neglect. The schizophrenia spectrum group reported significantly more physical abuse and physical neglect than the affective group.

CONCLUSION

A high prevalence of CT in patients with severe mental disorder was detected. This reminds us of the importance of exploring this issue when we treat such patients. The mechanisms behind these differences are unclear. Further research is needed to study potential associations between CT and the clinical picture of the disorder.

Distinguishing young people with emerging bipolar disorders from those with unipolar depression

BACKGROUND

To facilitate early intervention, there is a need to distinguish unipolar versus bipolar illness trajectories in adolescents and young adults with adult-type mood disorders.

METHODS

Detailed clinical and neuropsychological evaluation of 308 young persons (aged 12 to 30 years) with moderately severe unipolar and bipolar affective disorders.

RESULTS

Almost 30% (90/308) of young people (mean age=19.4±4.4yr) presenting for care with affective disorders met criteria for a bipolar-type syndrome (26% with bipolar I). Subjects with bipolar- and unipolar-type syndromes were of similar age (19.8 vs. 19.2yr) and reported comparable ages of onset (14.5 vs. 14.3yr). Clinically, those subjects with unipolar and bipolar-type disorders reported similar levels of psychological distress, depressive symptoms, current role impairment, neuropsychological dysfunction and alcohol or other substance misuse. Subjects with unipolar disorders reported more social anxiety (p<0.01). Subjects with bipolar disorders were more likely to report a family history of bipolar (21% vs. 11%; [χ(2)=4.0, p<.05]) or psychotic (19% vs. 9%; [χ(2)=5.5, p<.05]), or substance misuse (35% vs. 23%; [χ(2)=3.9, p<.05]), but not depressive (48% vs. 53%; χ(2)=0.3, p=.582]) disorders.

CONCLUSIONS

Young subjects with bipolar disorders were best discriminated by a family history of bipolar, psychotic or substance use disorders. Early in the course of illness, clinical features of depression, or neuropsychological function, do not readily differentiate the two illness trajectories.

Adaptive Associations between Social Cognition and Emotion Regulation are Absent in Schizophrenia and Bipolar Disorder

Schizophrenia (SZ) and bipolar disorder (BD) are associated with impairments in facial emotion perception and Theory of Mind (ToM). These social cognitive skills deficits may be related to a reduced capacity to effectively regulate one’s own emotions according to the social context. We therefore set out to examine the relationship between social cognitive abilities and the use of cognitive strategies for regulating negative emotion in SZ and BD. Participants were 56 SZ, 33 BD, and 58 healthy controls (HC) who completed the Ekman 60-faces test of facial emotion recognition; a sub-set of these participants also completed The Awareness of Social Inference Test (TASIT) and the Cognitive Emotion Regulation Questionnaire (CERQ). SZ participants demonstrated impairments in emotion perception on both the Ekman and the TASIT Emotion Evaluation tests relative to BD and HC. While both SZ and BD patients showed ToM deficits (i.e., perception of sarcasm and lie) compared to HC, SZ patients demonstrated significantly greater ToM impairment compared to BD. There were also distinct patterns of cognitive strategies used to regulate emotion in both patient groups: those with SZ were more likely to engage in catastrophizing and rumination, while BD subjects were more likely to blame themselves and were less likely to engage in positive reappraisal, relative to HC. In addition, those with SZ were more likely to blame others compared to BD. Associations between social cognition and affect regulation were revealed for HC only: TASIT performance was negatively associated with more frequent use of rumination, catastrophizing, and blaming others, such that more frequent use of maladaptive cognitive emotion regulation strategies was associated with poor social cognitive performance. These associations were not present in either patient group. However, both SZ and BD patients demonstrated poor ToM performance and aberrant use of emotion regulation strategies consistent with previous studies. SZ also showed basic emotion recognition deficits relative to BD and HC. That there were no associations between social cognition and the capacity to self-regulate negative emotion in SZ and BD (in the context of poor social cognition and maladaptive regulatory strategies) suggests that dysfunction in fronto-limbic brain networks may underpin both social cognitive deficits and the use of maladaptive cognitive strategies in these disorders, albeit by potentially different routes.

Neurocognitive Functioning in Schizophrenia and Bipolar Disorder: Clarifying Concepts of Diagnostic Dichotomy vs. Continuum

The Kraepelinian dichotomy posits that patients with schizophrenia (SCZ) and bipolar disorder (BD) present as two separate psychotic entities such that they differ in terms of clinical severity including neurocognitive functioning. Our study aimed to specifically compare and contrast the level of neurocognitive functioning between SCZ and BD patients and identify predictors of their poor neurocognitive functioning. We hypothesized that patients with SCZ had a similar level of neurocognitive impairment compared with BD. About 49 healthy controls (HC), 72 SCZ, and 42 BD patients who were matched for age, gender, and premorbid IQ were administered the Brief Assessment of Cognition battery (BAC). Severity of psychopathology and socio-occupational functioning were assessed for both patients groups. Both BD and SCZ groups demonstrated similar patterns of neurocognitive deficits across several domains (verbal memory, working memory, semantic fluency, processing speed) compared with HC subjects. However, no significant difference was found in neurocognitive functioning between BD and SCZ patients, suggesting that both patient groups suffer the same degree of neurocognitive impairment. Patients with lower level of psychosocial functioning [F (1,112) = 2.661, p = 0.009] and older age [F (1,112) = -2.625, p = 0.010], not diagnosis or doses of psychotropic medications, predicted poorer overall neurocognitive functioning as measured by the lower BAC composite score. Our findings of comparable neurocognitive impairments between SCZ and BD affirm our hypothesis and support less the Kraepelinian concept of dichotomy but more of a continuum of psychotic spectrum conditions. This should urge clinicians to investigate further the underlying neural basis of these neurocognitive deficits, and be attentive to the associated socio-demographic and clinical profile in order to recognize and optimize early the management of the widespread neurocognitive deficits in patients with SCZ and BD.

Cognitive impairment in bipolar disorder and schizophrenia: a systematic review

AIMS

Previous comparisons of cognitive decline among patients with bipolar disorder (BD) and schizophrenia (SZ) have found somehow quite similar profiles of deficits, but results have varied between studies. Therefore an extensive and thoughtful systematic review of the matter is warranted.

METHODS

Studies were found through systematic search (PubMed) following PRISMA guidelines. To be included, studies must have assessed the following cognitive functions: executive functions, memory, IQ, attention-concentration, and perceptuomotor function. In order to make comparison between the two entities, studies should include BD patients with operationally defined euthymia, schizophrenic patients in remission, and third group of healthy control patients. Comparisons were made after controlling for years of schooling and residual affective symptoms.

RESULTS

We found that overall both SZ and BD patients present deficits on all neurocognitive measures compared to healthy controls. In particular, SZ patients show more severe and pervasive cognitive deficits while BD patients present a milder and more confined impairment. In addition, evidence from the literature suggests that SZ and BD patients share a similar cognitive impairment profile with different degrees of deficits. Therefore, the difference between the two groups seems to be more quantitative (degree of deficit) rather than qualitative (profile), supporting a dimensional approach to the two clinical entities. Limitations of the present review includes the impossibility to control for effects of medication, varying time required for assessment across studies, illness diagnosis reliability, and course severity.

CONCLUSION

Patients with BD might exhibit a cognitive impairment that could be similar to SZ in terms of their profile, although patients with SZ may have more severe and widespread impairments.

Neuropsychological performance and family history in children at age 7 who develop adult schizophrenia or bipolar psychosis in the New England Family Studies

BACKGROUND

Persons developing schizophrenia (SCZ) manifest various pre-morbid neuropsychological deficits, studied most often by measures of IQ. Far less is known about pre-morbid neuropsychological functioning in individuals who later develop bipolar psychoses (BP). We evaluated the specificity and impact of family history (FH) of psychosis on pre-morbid neuropsychological functioning.

METHOD

We conducted a nested case-control study investigating the associations of neuropsychological data collected systematically at age 7 years for 99 adults with psychotic diagnoses (including 45 SCZ and 35 BP) and 101 controls, drawn from the New England cohort of the Collaborative Perinatal Project (CPP). A mixed-model approach evaluated full-scale IQ, four neuropsychological factors derived from principal components analysis (PCA), and the profile of 10 intelligence and achievement tests, controlling for maternal education, race and intra-familial correlation. We used a deviant responder approach (<10th percentile) to calculate rates of impairment.

RESULTS

There was a significant linear trend, with the SCZ group performing worst. The profile of childhood deficits for persons with SCZ did not differ significantly from BP. Neuropsychological impairment was identified in 42.2% of SCZ, 22.9% of BP and 7% of controls. The presence of psychosis in first-degree relatives (FH+) significantly increased the severity of childhood impairment for SCZ but not for BP.

CONCLUSIONS

Pre-morbid neuropsychological deficits are found in a substantial proportion of children who later develop SCZ, especially in the SCZ FH+ subgroup, but less so in BP, suggesting especially impaired neurodevelopment underlying cognition in pre-SCZ children. Future work should assess genetic and environmental factors that explain this FH effect.

An environmental analysis of genes associated with schizophrenia: hypoxia and vascular factors as interacting elements in the neurodevelopmental model

Investigating and understanding gene-environment interaction (G × E) in a neurodevelopmentally and biologically plausible manner is a major challenge for schizophrenia research. Hypoxia during neurodevelopment is one of several environmental factors related to the risk of schizophrenia, and links between schizophrenia candidate genes and hypoxia regulation or vascular expression have been proposed. Given the availability of a wealth of complex genetic information on schizophrenia in the literature without knowledge on the connections to environmental factors, we now systematically collected genes from candidate studies (using SzGene), genome-wide association studies (GWAS) and copy number variation (CNV) analyses, and then applied four criteria to test for a (theoretical) link to ischemia-hypoxia and/or vascular factors. In all, 55% of the schizophrenia candidate genes (n=42 genes) met the criteria for a link to ischemia-hypoxia and/or vascular factors. Genes associated with schizophrenia showed a significant, threefold enrichment among genes that were derived from microarray studies of the ischemia-hypoxia response (IHR) in the brain. Thus, the finding of a considerable match between genes associated with the risk of schizophrenia and IHR and/or vascular factors is reproducible. An additional survey of genes identified by GWAS and CNV analyses suggested novel genes that match the criteria. Findings for interactions between specific variants of genes proposed to be IHR and/or vascular factors with obstetric complications in patients with schizophrenia have been reported in the literature. Therefore, the extended gene set defined here may form a reasonable and evidence-based starting point for hypothesis-based testing of G × E interactions in clinical genetic and translational neuroscience studies.

The impact of a history of psychotic symptoms on cognitive function in euthymic bipolar patients: a comparison with schizophrenic patients and healthy controls

BACKGROUND

About two-thirds of patients with bipolar disorder (BD) have a lifetime history of at least one psychotic symptom.

OBJECTIVE

To compare the neurocognitive performance of four groups: BD patients with and without a history of psychotic symptoms (BD HPS+ and BD HPS-, respectively); patients with schizophrenia (SZ); and healthy control (HC) subjects.

METHOD

In this cross-sectional study, 35 stabilized patients with SZ, 79 euthymic (44 HPS+ and 35 HPS-) patients with BD, and 50 HC were administered a comprehensive battery of neuropsychological tests.

RESULTS

There was worse neurocognitive functioning in both BD and SZ patients compared to HC. Overall, data from both groups of BD patients did not differ on sociodemographic, clinical, or neurocognitive variables. However, BD HPS+ patients had significantly more negative symptoms, as measured by the Positive and Negative Syndrome Scale (PANSS), and showed a trend toward worse performance on executive functions compared to BD HPS- patients. Moreover, both BD groups had better performance on all neurocognitive tests compared to SZ group.

CONCLUSIONS

Neurocognitive dysfunction may be more marked in SZ than in BD, yet qualitatively similar. A history of past psychotic symptoms in BD was not associated with more severe cognitive impairment during euthymia. Therefore, BD with psychotic symptoms does not appear to be a distinct neurocognitive phenotype.

Rare copy number variants in neuropsychiatric disorders: Specific phenotype or not?

From a number of genome-wide association studies it was shown that de novo and/or rare copy number variants (CNVs) are found at an increased frequency in neuropsychiatric diseases. In this study we examined the prevalence of CNVs in six genomic regions (1q21.1, 2p16.3, 3q29, 15q11.2, 15q13.3, and 16p11.2) previously implicated in neuropsychiatric diseases. Hereto, a cohort of four neuropsychiatric disorders (schizophrenia, bipolar disorder, major depressive disorder, and intellectual disability) and control individuals from three different populations was used in combination with Multilpex Amplicon Quantifiaction (MAQ) assays, capable of high resolution (kb range) and custom-tailored CNV detection. Our results confirm the etiological candidacy of the six selected CNV regions for neuropsychiatric diseases. It is possible that CNVs in these regions can result in disturbed brain development and in this way lead to an increased susceptibility for different neuropsychiatric disorders, dependent on additional genetic and environmental factors. Our results also suggest that the neurodevelopmental component is larger in the etiology of schizophrenia and intellectual disability than in mood disorders. Finally, our data suggest that deletions are in general more pathogenic than duplications. Given the high frequency of the examined CNVs (1-2%) in patients of different neuropsychiatric disorders, screening of large cohorts with an affordable and feasible method like the MAQ assays used in this study is likely to result in important progress in unraveling the genetic factors leading to an increased susceptibility for several psychiatric disorders.

Executive dysfunction and memory impairment in schizoaffective disorder: a comparison with bipolar disorder, schizophrenia and healthy controls

BACKGROUND

Deficits in memory and executive performance are well-established features of bipolar disorder and schizophrenia. By contrast, data on cognitive impairment in schizoaffective disorder are scarce and the findings are conflicting.

METHOD

We used the Wechsler Memory Scale (WMS-III) and the Behavioural Assessment of the Dysexecutive Syndrome (BADS) to test memory and executive function in 45 schizophrenic patients, 26 schizomanic patients and 51 manic bipolar patients in comparison to 65 healthy controls. The patients were tested when acutely ill.

RESULTS

All three patient groups performed significantly more poorly than the controls on global measures of memory and executive functioning, but there were no differences among the patient groups. There were few differences in memory and executive function subtest scores within the patient groups. There were no differences in any test scores between manic patients with and without psychotic symptoms.

CONCLUSIONS

Schizophrenic, schizomanic and manic patients show a broadly similar degree of executive and memory deficits in the acute phase of illness. Our results do not support a categorical differentiation across different psychotic categories with regard to neuropsychological deficits.

Linear and non-linear associations of symptom dimensions and cognitive function in first-onset psychosis

BACKGROUND

Associations between symptom dimensions and cognition have been mainly studied in non-affective psychosis. The present study investigated whether previously reported associations between cognition and four symptom dimensions (reality distortion, negative symptoms, disorganisation and depression) in non-affective psychosis generalise to a wider spectrum of psychoses. It also extended the research focus to mania, a less studied symptom dimension.

METHODS

Linear and non-linear (quadratic, curvilinear or inverted-U-shaped) associations between cognition and the above five symptom dimensions were examined in a population-based cohort of 166 patients with first-onset psychosis using regression analyses.

RESULTS

Negative symptoms showed statistically significant linear associations with IQ and processing speed, and a significant curvilinear association with verbal memory/learning. Significant quadratic associations emerged between mania and processing speed and mania and executive function. The contributions of mania and negative symptoms to processing speed were independent of each other. The findings did not differ between affective and non-affective psychoses, and survived correction for multiple testing.

CONCLUSIONS

Mania and negative symptoms are associated with distinct patterns of cerebral dysfunction in first-onset psychosis. A novel finding is that mania relates to cognitive performance by a complex response function (inverted-U-shaped relationship). The associations of negative symptoms with cognition include both linear and quadratic elements, suggesting that this dimension is not a unitary concept. These findings cut across affective and non-affective psychoses, suggesting that different diagnostic entities within the psychosis spectrum lie on a neurobiological continuum.

Sustained attention in bipolar I disorder patients with familial psychosis and their first-degree relatives

Sustained attention (SA) was examined in patients with familial, psychotic Bipolar Disorder (BD) (n=43), their non-bipolar, non-psychotic relatives (n=44) and controls (n=47). Patients were impaired compared to relatives, but the latter did not differ from controls. Having a relative with familial, psychotic BD does not confer risk for SA deficits.

Are obstetrical, perinatal, and infantile difficulties associated with pediatric bipolar disorder?

OBJECTIVES

Despite increasing acknowledgement of bipolar disorder (BD) in childhood, there is a paucity of literature that has investigated obstetrical, perinatal, and infantile difficulties and their potential link with BD. To this end, we examined difficulties during delivery, immediate post-birth, and infancy and the association with BD in childhood.

METHODS

From two similarly designed, ongoing, longitudinal, case-control family studies of pediatric BD (N = 327 families), we analyzed 338 children and adolescents [mean (± standard deviation) age: 12.00 ± 3.37 years]. We stratified them into three groups: healthy controls (N = 98), BD probands (N = 120), and their non-affected siblings (N = 120). All families were comprehensively assessed with a structured psychiatric diagnostic interview for psychopathology and substance use. Mothers were directly questioned regarding the pregnancy, delivery, and infancy difficulties that occurred with each child using a module from the Diagnostic Interview for Children and Adolescents-Parent Version (DICA-P).

RESULTS

Mothers of BD subjects were more likely to report difficulties during infancy than mothers of controls [odds ratio (95% confidence interval) = 6.6 (3.0, 14.6)]. Specifically, children with BD were more likely to have been reported as a stiffened infant [7.2 (1.1, 47.1)] and more likely to have experienced 'other' infantile difficulties [including acting colicky; 4.9 (1.3, 18.8)] compared to controls. We found no significant differences between groups in regards to obstetrical or perinatal difficulties (all p values > 0.05).

CONCLUSIONS

While our results add to previous literature on obstetrical and perinatal difficulties and BD, they also highlight characteristics in infancy that may be prognostic indicators for pediatric BD.

Relational memory in psychotic bipolar disorder

OBJECTIVES

Recent research has highlighted the phenotypic and genetic overlap of bipolar disorder and schizophrenia. Cognitive deficits in bipolar disorder parallel those seen in schizophrenia, particularly for bipolar disorder patients with a history of psychotic features. Here we explored whether relational memory deficits, which are prominent in schizophrenia, are also present in patients with psychotic bipolar disorder.

METHODS

We tested 25 patients with psychotic bipolar disorder on a relational memory paradigm previously employed to quantify deficits in schizophrenia. During the training, participants learned to associate a set of faces and background scenes. During the testing, participants viewed a single background overlaid by three trained faces and were asked to recall the matching face, which was either present (Match trials) or absent (Non-Match trials). Explicit recognition and eye-movement data were collected and compared to those for 28 schizophrenia patients and 27 healthy subjects from a previously published dataset.

RESULTS

Contrary to our prediction, we found psychotic bipolar disorder patients were less impaired in relational memory than schizophrenia subjects. Bipolar disorder subjects showed eye-movement behavior similar to healthy controls, whereas schizophrenia subjects were impaired relative to both groups. However, bipolar disorder patients with current delusions and/or hallucinations were more impaired than bipolar disorder patients not currently experiencing these symptoms.

CONCLUSIONS

We found that patients with psychotic bipolar disorder had better relational memory performance than schizophrenia patients, indicating that a history of psychotic symptoms does not lead to a significant relational memory deficit.

Childhood cognitive function and adult psychopathology: associations with psychotic and non-psychotic symptoms in the general population

BACKGROUND

Lower cognitive ability in childhood is associated with increased risk of future schizophrenia, but its relationship with adult psychotic-like experiences and other psychopathology is less understood.

AIMS

To investigate whether this childhood risk factor is shared with adult subclinical psychiatric phenotypes including psychotic-like experiences and general psychiatric morbidity.

METHOD

A population-based sample of participants born in Great Britain during 1 week in March 1946 was contacted up to 20 times between ages 6 weeks and 53 years. Cognition was assessed at ages 8, 11 and 15 years using a composite of age-appropriate verbal and non-verbal cognitive tests. At age 53 years, psychotic-like experiences were self-reported by 2918 participants using four items from the Psychosis Screening Questionnaire and general psychiatric morbidity was assessed using the scaled version of the General Health Questionnaire (GHQ-28).

RESULTS

Psychotic-like experiences were reported by 22% of participants, and were highly comorbid with other psychopathology. Their presence in adults was significantly associated with poorer childhood cognitive test scores at ages 8 and 15 years, and marginally so at age 11 years. In contrast, high GHQ scores were not associated with poorer childhood cognition after adjustment for the presence of psychotic-like experiences.

CONCLUSIONS

Psychotic and non-psychotic psychopathologic symptoms are highly comorbid in the general population. Lower childhood cognitive ability is a risk factor for psychotic-like experiences in mid-life; these phenomena may be one end of a continuum of phenotypic expression driven by variation in early neurodevelopment.

Patients with functional psychoses show similar visual backward masking deficits

Recent genetic, behavioral, and clinical studies suggest that functional psychoses (schizophrenia, bipolar disorder, schizoaffective disorder), previously thought to be distinct from each other, may belong to one continuum. The shine-through masking paradigm is a potential endophenotype of schizophrenia with high sensitivity and specificity for discriminating between patients, their clinically unaffected relatives, and healthy controls. Hence, if schizophrenia, bipolar disorder and schizoaffective disorder belong to one common disease, strong masking deficits are expected to occur in all three diseases whereas no masking deficits are expected for abstinent alcoholic or depressive patients. Indeed, we found masking to be much stronger in psychotic patients compared to controls and to depressive patients and abstinent alcoholics, who performed on similar levels.

Structural changes in the hippocampus and amygdala at first episode of psychosis

Hippocampus and amygdala changes have been implicated in the pathophysiology and symptomatology of both schizophrenia (SCZ) and bipolar disorder (BD). However relationships between illness course, neuropathological changes and variations in symptomatology remain unclear. This investigation examined the associations between hippocampus and amygdala volumes and symptom dimensions in schizophrenia and bipolar disorder patients after their first episode of psychosis. Symptom severity was associated with decreases in hippocampus/amygdala complex volume across groups. In keeping with previous work bilateral hippocampus and amygdala volume reductions were also identified in the SCZ patients while in BD patients only evidence of amygdala inflation reached significance. The study concludes that there appear to be important relationships between volume changes in the hippocampus and amygdala and dimensions and severity of symptomatology in psychosis. Structural alterations are apparent in both SCZ and BD after first episode of psychosis but present differently in each illness and are more severe in SCZ.

Review of functional magnetic resonance imaging studies comparing bipolar disorder and schizophrenia

OBJECTIVE

Although bipolar disorder (BD) and schizophrenia (SCZ) have a number of clinical features and certain susceptibility genes in common, they are considered separate disorders, and it is unclear which aspects of pathophysiology are specific to each condition. Here, we examine the functional magnetic resonance imaging (fMRI) literature to determine the evidence for diagnosis-specific patterns of brain activation in the two patient groups.

METHOD

A systematic search was performed to identify fMRI studies directly comparing BD and SCZ to examine evidence for diagnosis-specific activation patterns. Studies were categorized into (i) those investigating emotion, reward, or memory, (ii) those describing executive function or language tasks, and (iii) those looking at the resting state or default mode networks. Studies reporting estimates of sensitivity and specificity of classification are also summarized, followed by studies reporting associations with symptom severity measures.

RESULTS

In total, 21 studies were identified including patients (n = 729) and healthy subjects (n = 465). Relative over-activation in the medial temporal lobe and associated structures was found in BD versus SCZ in tasks involving emotion or memory. Evidence of differences between the disorders in prefrontal regions was less consistent. Accuracy values for assignment of diagnosis were generally lower in BD than in SCZ. Few studies reported significant symptom associations; however, these generally implicated limbic regions in association with manic symptoms.

CONCLUSIONS

Although there are a limited number of studies and a cautious approach is warranted, activation differences were found in the medial temporal lobe and associated limbic regions, suggesting the presence of differences in the neurobiological substrates of SCZ and BD. Future studies examining symptom dimensions, risk-associated genes, and the effects of medication will aid clarification of the mechanisms behind these differences.

Do child abuse and maltreatment increase risk of schizophrenia?

INTRODUCTION

Although childhood abuse is a recognised risk factor for depression, post-traumatic stress disorder, and substance misuse, its role in the aetiology of psychotic disorder remained controversial. This is in part because the putative effect of childhood trauma on psychosis has been mostly evaluated by small, cross sectional, uncontrolled studies that raised methodological issues.

METHODS

Papers concerning the association between childhood trauma and psychotic disorders (to November, 2011) were identified using a comprehensive search of PubMed, Psychinfo, and Scopus and analysing reference list of relevant papers. A narrative synthesis was used to summarise results.

RESULTS

An association between childhood abuse and psychotic symptoms was consistently reported by large cross sectional surveys with an effect ranging from 1.7 to 15. However, we cannot conclude that the relationship is causal as lack of longitudinal studies prevent us from fully excluding alternative explanations such as reverse causality. Gender, cannabis use, and depressive and post-traumatic stress disorder symptoms appear to moderate the effect of childhood trauma on psychotic disorders. However, specificity of childhood abuse in psychotic disorders and, particularly, in schizophrenia has not been demonstrated.

CONCLUSION

Although the association between childhood abuse and psychosis has been replicated, the etiological role of such early adversity has yet to be fully clarified. So far none of the studies reported support the hypothesis that childhood abuse is either sufficient or necessary to develop a psychotic disorder. It seems likely that any effect of childhood abuse on schizophrenia needs to be understood in terms of genetic susceptibility and interaction with other environmental risk factors.

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.

Cortical volume, surface area, and thickness in schizophrenia and bipolar disorder

BACKGROUND

Magnetic resonance imaging studies have shown that structural brain abnormalities are present in both schizophrenia and bipolar disorder. Most previous studies have focused on brain tissue volumes, but advances in neuroimaging data processing have made it possible to separate cortical area and cortical thickness. The purpose of the present study was to provide a more complete picture of cortical morphometric differences in schizophrenia and bipolar disorder, decomposing cortical volume into its constituent parts, cortical thickness and cortical area.

METHODS

We analyzed magnetic resonance imaging images from a sample of 173 patients with schizophrenia, 139 patients with bipolar disorder, and 207 healthy control subjects. Maps of cortical volume, area, and thickness across the continuous cortical surface were generated within groups and compared between the groups.

RESULTS

There were widespread reductions in cortical volume in schizophrenia relative to healthy control subjects and patients with bipolar disorder type I. These reductions were mainly driven by cortical thinning, but there were also cortical area reductions in more circumscribed regions, which contributed to the observed volume reductions.

CONCLUSIONS

The current surface-based methodology allows for a distinction between cortical thinning and reduction in cortical area and reveals that cortical thinning is the most important factor in volume reduction in schizophrenia. Cortical area reduction was not observed in bipolar disorder type I and may be unique to schizophrenia.

A twin study of schizoaffective-mania, schizoaffective-depression, and other psychotic syndromes

The nosological status of schizoaffective disorders remains controversial. Twin studies are potentially valuable for investigating relationships between schizoaffective-mania, schizoaffective-depression, and other psychotic syndromes, but no such study has yet been reported. We ascertained 224 probandwise twin pairs [106 monozygotic (MZ), 118 same-sex dizygotic (DZ)], where probands had psychotic or manic symptoms, from the Maudsley Twin Register in London (1948-1993). We investigated Research Diagnostic Criteria schizoaffective-mania, schizoaffective-depression, schizophrenia, mania and depressive psychosis primarily using a non-hierarchical classification, and additionally using hierarchical and data-derived classifications, and a classification featuring broad schizophrenic and manic syndromes without separate schizoaffective syndromes. We investigated inter-rater reliability and co-occurrence of syndromes within twin probands and twin pairs. The schizoaffective syndromes showed only moderate inter-rater reliability. There was general significant co-occurrence between syndromes within twin probands and MZ pairs, and a trend for schizoaffective-mania and mania to have the greatest co-occurrence. Schizoaffective syndromes in MZ probands were associated with relatively high risk of a psychotic syndrome occurring in their co-twins. The classification of broad schizophrenic and manic syndromes without separate schizoaffective syndromes showed improved inter-rater reliability, but high genetic and environmental correlations between the two broad syndromes. The results are consistent with regarding schizoaffective-mania as due to co-occurring elevated liability to schizophrenia, mania, and depression; and schizoaffective-depression as due to co-occurring elevated liability to schizophrenia and depression, but with less elevation of liability to mania. If in due course schizoaffective syndromes show satisfactory inter-rater reliability and some specific etiological factors they could alternatively be regarded as partly independent 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.

fMRI responses to emotional faces in children and adolescents at genetic risk for psychiatric illness share some of the features of depression

BACKGROUND

Fronto-limbic regions of the brain including the sub-genual (sgPFC) and medial prefrontal (mPFC) cortices are central to processing emotionally salient and hedonic stimuli (Mayberg, 2009) and implicated in depression. The relevance of cortico-limbic models of emotion and reward processing in children with genetic risk for psychiatric disorders has not been assessed.

METHODS

Here we studied adolescents at risk for schizophrenia (HRS) and controls (HC) using an event-related fMRI continuous affective appraisal task. HRS were divided into sub-groups based on the presence or absence of negative symptoms (Miller et al., 2003), HRS_NS+ and HRS_NS- respectively. Brain responses to positive, negative and neutral emotional stimuli were estimated.

RESULTS

Consistent with observations in the depressive phenotype, for positively valenced stimuli, HRS_NS+ (relative to HC and HRS_NS-) were characterized by hypo-responsivity of the sgPFC and the mPFC, but hyper-responsivity of the mid-brain. sgPFC and mPFC signals were coupled across groups.

LIMITATIONS

Such studies can benefit from larger sample sizes, though our observed effect sizes were in the moderate to large range.

CONCLUSIONS

Children and adolescents at risk for psychiatric illness and who evince reliably present negative symptoms show brain responses to socially rewarding stimuli similar to those observed in depression. Studies in at-risk children and adolescents may be important in understanding how early manifestations of depression-like characteristics impact brain function.

Premorbid school performance in twins concordant and discordant for bipolar disorder

BACKGROUND

Although the genetic risk to develop bipolar disorder is present from conception, the first frank symptoms of the illness generally become evident in late adolescence or early adulthood. However, except for pediatric bipolar disorder (PBD), it is still unclear when the first signs of the illness in adults become apparent and whether these are related to the genetic risk to develop bipolar disorder. This study examined whether underperformance at school precedes the onset of the illness and is a genetically related risk marker for developing bipolar disorder.

METHODS

Information on school performance was obtained using objective archival data from 53 bipolar twin pairs (24 monozygotic (MZ), 29 dizygotic (DZ)) and 42 healthy matched control twin pairs (23 MZ, 19 DZ).

RESULTS

Affected twin pairs completed significantly fewer years of education than did control twin pairs with no difference between bipolar patients and their non-bipolar cotwins. The underperformance at school in the affected twin pairs occurred in early adolescence at a significantly younger age than the control twin pairs and preceded the onset of the first frank episode of bipolar disorder by thirteen years. Median age at onset of underperformance was not different in the patients and their non-bipolar cotwins. The association between liability of bipolar disease and age of first underperformance was significant and could be explained by genetic factors.

LIMITATIONS

The sample is not a population based twin sample.

CONCLUSION

Underperformance at school during early adolescence may be a genetic marker for the vulnerability to develop bipolar disorder.

The deletion of STOP/MAP6 protein in mice triggers highly altered mood and impaired cognitive performances

The microtubule-associated Stable Tubulie Only Polypeptide (STOP; also known as MAP6) protein plays a key role in neuron architecture and synaptic plasticity, the dysfunctions of which are thought to be implicated in the pathophysiology of psychiatric diseases. The deletion of STOP in mice leads to severe disorders reminiscent of several schizophrenia-like symptoms, which are also associated with differential alterations of the serotonergic tone in somas versus terminals. In STOP knockout (KO) compared with wild-type mice, serotonin (5-HT) markers are found to be markedly accumulated in the raphe nuclei and, in contrast, deeply depleted in all serotonergic projection areas. In the present study, we carefully examined whether the 5-HT imbalance would lead to behavioral consequences evocative of mood and/or cognitive disorders. We showed that STOP KO mice exhibited depression-like behavior, associated with a decreased anxiety-status in validated paradigms. In addition, although STOP KO mice had a preserved very short-term memory, they failed to perform well in all other learning and memory tasks. We also showed that STOP KO mice exhibited regional imbalance of the norepinephrine tone as observed for 5-HT. As a consequence, mutant mice were hypersensitive to acute antidepressants with different selectivity. Altogether, these data indicate that the deletion of STOP protein in mice caused deep alterations in mood and cognitive performances and that STOP protein might have a crucial role in the 5-HT and norepinephrine networks development.

Exposure to obstetric complications in relation to subsequent psychiatric disorders of adolescent inpatients: specific focus on gender differences

BACKGROUND

Exposure to obstetric complications is known to be associated with subsequent development of psychiatric disorders. However, earlier findings are mainly based on adult populations having a long follow-up time for onset of psychiatric illness. We examined whether the association of obstetric complications with severe mental disorders is already seen in a population of underage adolescents admitted to psychiatric inpatient care.

METHOD

The study population was a clinical sample of adolescents (n = 508) aged 12-17 years admitted to psychiatric hospital. DSM-IV diagnoses of the psychiatric disorders of the adolescents as well as information on obstetric (i.e., pregnancy, delivery and perinatal) complications and substance use during pregnancy reported by the mothers of the adolescents were based on the semi-structured Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime.

RESULTS

A total of 96 (19%) adolescents had been exposed to obstetric complications. The prevalence of pregnancy, delivery or perinatal complications reported by the mothers of the offspring was 55 (57%), 57 (59%) and 13 (14%), respectively. Among adolescents with conduct disorder, exposure to delivery complications was more common among males compared to females (16 vs. 5%, p = 0.006); this was particularly true for section delivery (7 vs. 1%, p = 0.023). A trend towards a significant gender difference was also found among adolescents with anxiety disorder (21 vs. 8%, p = 0.085).

CONCLUSIONS

Boys seem to be more vulnerable to the exposure of delivery complications than girls. Exposure to obstetric complication may be associated with development of subsequent psychiatric disorder; particularly conduct disorder of adolescent boys.