Differentiating Biomarker Features and Familial Characteristics of B-SNIP Psychosis Biotypes

Idiopathic psychosis shows considerable biological heterogeneity across cases. B-SNIP used psychosis-relevant biomarkers to identity psychosis Biotypes, which will aid etiological and targeted treatment investigations. Psychosis probands from the B-SNIP consortium (n = 1907), their first-degree biological relatives (n = 705), and healthy participants (n = 895) completed a biomarker battery composed of cognition, saccades, and auditory EEG measurements. ERP quantifications were substantially modified from previous iterations of this approach. Multivariate integration reduced multiple biomarker outcomes to 11 "bio-factors". Twenty-four different approaches indicated bio-factor data among probands were best distributed as three subgroups. Numerical taxonomy with k-means constructed psychosis Biotypes, and rand indices evaluated consistency of Biotype assignments. Psychosis subgroups, their non-psychotic first-degree relatives, and healthy individuals were compared across bio-factors. The three psychosis Biotypes differed significantly on all 11 bio-factors, especially prominent for general cognition, antisaccades, ERP magnitude, and intrinsic neural activity. Rand indices showed excellent consistency of clustering membership when samples included at least 1100 subjects. Canonical discriminant analysis described composite bio-factors that simplified group comparisons and captured neural dysregulation, neural vigor, and stimulus salience variates. Neural dysregulation captured Biotype-2, low neural vigor captured Biotype-1, and deviations of stimulus salience captured Biotype-3. First-degree relatives showed similar patterns as their Biotyped proband relatives on general cognition, antisaccades, ERP magnitudes, and intrinsic brain activity. Results extend previous efforts by the B-SNIP consortium to characterize biologically distinct psychosis Biotypes. They also show that at least 1100 observations are necessary to achieve consistent outcomes. First-degree relative data implicate specific bio-factor deviations to the subtype of their proband and may inform studies of genetic risk.

Characterization of childhood trauma, hippocampal mediation and Cannabis use in a large dataset of psychosis and non-psychosis individuals

BACKGROUND

Cannabis use (CA) and childhood trauma (CT) independently increase the risk of earlier psychosis onset; but their interaction in relation to psychosis risk and association with endocannabinoid-receptor rich brain regions, i.e. the hippocampus (HP), remains unclear. The objective was to determine whether lower age of psychosis onset (AgePsyOnset) is associated with CA and CT through mediation by the HP volumes, and genetic risk, as measured by schizophrenia polygene scores (SZ-PGRS).

METHODS

Cross-sectional, case-control, multicenter sample from 5 metropolitan US regions. Participants (n = 1185) included 397 controls not affected by psychosis (HC); 209 participants with bipolar disorder type-1; 279 with schizoaffective disorder; and 300 with schizophrenia (DSM IV-TR). CT was assessed using the Childhood Trauma Questionnaire (CTQ); CA was assessed by self-reports and trained clinical interviewers. Assessment included neuroimaging, symptomatology, cognition and calculation of the SZ polygenic risk score (SZ-PGRS).

RESULTS

In survival analysis, CT and CA exposure interact to be associated with lower AgePsyOnset. At high CT or CA, CT or CA are individually sufficient to affect AgePsyOnset. CT relation with AgePsyOnset is mediated in part by the HP in CA users before AgePsyOnset. CA before AgePsyOnset is associated with higher SZ-PGRS and correlated with younger age at CA usage.

DISCUSSION

CA and CT interact to increase risk when moderate; while severe CT and/or CA abuse/dependence are each sufficient to affect AgePsyOnset, indicating a ceiling effect. Probands with/out CA before AgePsyOnset differ on biological variables, suggesting divergent pathways to psychosis.

FUNDING

MH077945; MH096942; MH096913; MH077862; MH103368; MH096900; MH122759.

Cognitive deficits, clinical variables, and white matter microstructure in schizophrenia: a multisite harmonization study

Cognitive deficits are among the best predictors of real-world functioning in schizophrenia. However, our understanding of how cognitive deficits relate to neuropathology and clinical presentation over the disease lifespan is limited. Here, we combine multi-site, harmonized cognitive, imaging, demographic, and clinical data from over 900 individuals to characterize a) cognitive deficits across the schizophrenia lifespan and b) the association between cognitive deficits, clinical presentation, and white matter (WM) microstructure. Multimodal harmonization was accomplished using T-scores for cognitive data, previously reported standardization methods for demographic and clinical data, and an established harmonization method for imaging data. We applied t-tests and correlation analysis to describe cognitive deficits in individuals with schizophrenia. We then calculated whole-brain WM fractional anisotropy (FA) and utilized regression-mediation analyses to model the association between diagnosis, FA, and cognitive deficits. We observed pronounced cognitive deficits in individuals with schizophrenia (p < 0.006), associated with more positive symptoms and medication dosage. Regression-mediation analyses showed that WM microstructure mediated the association between schizophrenia and language/processing speed/working memory/non-verbal memory. In addition, processing speed mediated the influence of diagnosis and WM microstructure on the other cognitive domains. Our study highlights the critical role of cognitive deficits in schizophrenia. We further show that WM is crucial when trying to understand the role of cognitive deficits, given that it explains the association between schizophrenia and cognitive deficits (directly and via processing speed).

A systematic mental health assessment of first-year students at a historically Black college

BACKGROUND

A systematic diagnostic mental health assessment was conducted with first-year students at Paul Quinn College, a small historically Black college/university (HBCU) in Dallas, Texas.

METHODS

A sample of 128 students was assessed with the Mini-International Neuropsychiatric Interview for DSM-5 and the Childhood Trauma Questionnaire.

RESULTS

Nearly one-third of students were diagnosed with a current psychiatric disorder, most commonly substance use disorders (17%) and major depressive disorder (9%). Despite these findings, few students had ever received psychiatric treatment, and considering their substantial trauma histories, few developed posttraumatic stress disorder, reflecting protective factors in the HBCU.

CONCLUSIONS

The prevalence of psychiatric disorders in this HBCU study is consistent with findings of studies conducted at predominately White institutions. However, the relatively low access to treatment of these HBCU students suggests relevant mental health care disparities in this population. Further research is needed to develop interventions designed to help connect HBCU students to mental health care.

An opportunity for primary prevention research in psychotic disorders

An opportunity has opened for research into primary prevention of psychotic disorders, based on progress in endophenotypes, genetics, and genomics. Primary prevention requires reliable prediction of susceptibility before any symptoms are present. We studied a battery of measures where published data supports abnormalities of these measurements prior to appearance of initial psychosis symptoms. These neurobiological and behavioral measurements included cognition, eye movement tracking, Event Related Potentials, and polygenic risk scores. They generated an acceptably precise separation of healthy controls from outpatients with a psychotic disorder. METHODS: The Bipolar and Schizophrenia Network on Intermediate Phenotypes (B-SNIP) measured this battery in an ancestry-diverse series of consecutively recruited adult outpatients with a psychotic disorder and healthy controls. Participants include all genders, 16 to 50 years of age, 261 with psychotic disorders (Schizophrenia (SZ) 109, Bipolar with psychosis (BPP) 92, Schizoaffective disorder (SAD) 60), 110 healthy controls. Logistic Regression, and an extension of the Linear Mixed Model to include analysis of pairwise interactions between measures (Environmental kernel Relationship Matrices (ERM)) with multiple iterations, were performed to predict case-control status. Each regression analysis was validated with four-fold cross-validation. RESULTS AND CONCLUSIONS: Sensitivity, specificity, and Area Under the Curve of Receiver Operating Characteristic of 85%, 62%, and 86%, respectively, were obtained for both analytic methods. These prediction metrics demonstrate a promising diagnostic distinction based on premorbid risk variables. There were also statistically significant pairwise interactions between measures in the ERM model. The strong prediction metrics of both types of analytic model provide proof-of-principle for biologically-based laboratory tests as a first step toward primary prevention studies. Prospective studies of adolescents at elevated risk, vs. healthy adolescent controls, would be a next step toward development of primary prevention strategies.

Confirmatory Efficacy and Safety Trial of Magnetic Seizure Therapy for Depression (CREST-MST): protocol for identification of novel biomarkers via neurophysiology

Background

Electroconvulsive therapy (ECT) is the most effective treatment for treatment-resistant depression (TRD), especially for acute suicidal ideation, but the associated cognitive adverse effects and negative stigma limit its use. Another seizure therapy under development is magnetic seizure therapy (MST), which could potentially overcome the restrictions associated with ECT with similar efficacy. The neurophysiological targets and mechanisms of seizure therapy, however, remain poorly understood.

Methods/design

This neurophysiological study protocol is published as a companion to the overall Confirmatory Efficacy and Safety Trial of Magnetic Seizure Therapy for Depression (CREST-MST) protocol that describes our two-site, double-blind, randomized, non-inferiority clinical trial to develop MST as an effective and safe treatment for TRD. Our aim for the neurophysiological component of the study is to evaluate two biomarkers, one to predict remission of suicidal ideation (primary outcome) and the other to predict cognitive impairment (secondary outcome). Suicidal ideation will be assessed through cortical inhibition, which according to our preliminary studies, correlates with remission of suicidal ideation. Cortical inhibition will be measured with simultaneous transcranial magnetic stimulation (TMS) and electroencephalography (EEG), TMS-EEG, which measures TMS-evoked EEG activity. Cognitive adverse effects associated with seizure therapy, on the contrary, will be evaluated via multiscale entropy analysis reflecting the complexity of ongoing resting-state EEG activity.

Discussion

ECT and MST are known to influence cortical inhibition associated with depression, suicidal ideation severity, and clinical outcome. Therefore, evaluating cortical inhibition and brain temporal dynamics will help understand the pathophysiology of depression and suicidal ideation and define new biological targets that could aid clinicians in diagnosing and selecting treatments. Resting-state EEG complexity was previously associated with the degree of cognitive side effects after a seizure therapy. This neurophysiological metric may help clinicians assess the risk for adverse effects caused by these useful and effective treatments.

Trial registration

ClinicalTrials.govNCT03191058. Registered on June 19, 2017.

Confirmatory Efficacy and Safety Trial of Magnetic Seizure Therapy for Depression (CREST-MST): study protocol for a randomized non-inferiority trial of magnetic seizure therapy versus electroconvulsive therapy

BACKGROUND

Electroconvulsive therapy (ECT) is well-established and effective for treatment-resistant depression (TRD), but in Canada and the USA, less than 1% of patients with TRD receive ECT mainly due to its cognitive adverse effects (i.e. amnesia). Thus, new treatment alternatives for TRD are urgently needed. One such treatment is magnetic seizure therapy (MST). ECT involves applying a train of high-frequency electrical stimuli to induce a seizure, whereas MST involves applying a train of high-frequency magnetic stimuli to induce a seizure.

METHODS

In this manuscript, we introduce our international, two-site, double-blinded, randomized, non-inferiority clinical trial to develop MST as an effective and safe treatment for TRD. This trial will compare the efficacy of MST to right unilateral ultra-brief pulse width electroconvulsive therapy (RUL-UB-ECT) with a combined primary endpoint of remission of depression and superior cognitive adverse effects in 260 patients with TRD. Amelioration of suicidal ideation will be assessed as a secondary endpoint. Inpatients or outpatients, over 18 years of age with a MINI International Neuropsychiatric Interview (MINI) diagnosis of non-psychotic major depressive disorder (MDD) can be enrolled in the study provided that they meet illness severity and full eligibility criteria. Participants are randomized to receive MST or RUL-UB ECT, 2-3 days per week over seven weeks, or a maximum of 21 treatments. The study will involve before-, during-, and after-treatment assessments of depression severity, suicidal ideation, subjective side-effects, and cognitive performance consistent with an intent-to-treat study design approach.

DISCUSSION

Positive results from this trial could have an immediate and tremendous impact for patients with TRD. If MST demonstrates comparable antidepressant treatment efficacy to ECT, but with greater cognitive safety, it could rapidly be adopted into clinical practice. Indeed, given that the administration of MST is nearly identical to ECT, the majority of ECT facilities in North America could readily adopt MST. Furthermore, the potential for cognitive safety could lead to improved treatment acceptability. Healthcare providers, patients and care partners, and policymakers would therefore demand this form of convulsive therapy.

TRIAL STATUS

Enrollment for this study began on June 26, 2018, and is estimated to complete recruitment by July 2024. At the time of submission, we have enrolled and randomized 117 participants.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03191058 , Registered on June 19, 2017. Primary sponsor: Daniel Blumberger (DMB), Principal Investigator Daniel.Blumberger@camh.ca , 416-535-8501 x 33662 Contact for public queries: DMB, Daniel.Blumberger@camh.ca Contact for scientific queries: ZJD, Zdaskalakis@health.ucsd.edu.

A Diagnosis and Biotype Comparison Across the Psychosis Spectrum: Investigating Volume and Shape Amygdala-Hippocampal Differences from the B-SNIP Study

OBJECTIVE

Brain-based Biotypes for psychotic disorders have been developed as part of the B-SNIP consortium to create neurobiologically distinct subgroups within idiopathic psychosis, independent from traditional phenomenological diagnostic methods. In the current study, we aimed to validate the Biotype model by assessing differences in volume and shape of the amygdala and hippocampus contrasting traditional clinical diagnoses with Biotype classification.

METHODS

A total of 811 participants from 6 sites were included: probands with schizophrenia (n = 199), schizoaffective disorder (n = 122), psychotic bipolar disorder with psychosis (n = 160), and healthy controls (n = 330). Biotype classification, previously developed using cognitive and electrophysiological data and K-means clustering, was used to categorize psychosis probands into 3 Biotypes, with Biotype-1 (B-1) showing reduced neural salience and severe cognitive impairment. MAGeT-Brain segmentation was used to determine amygdala and hippocampal volumetric data and shape deformations.

RESULTS

When using Biotype classification, B-1 showed the strongest reductions in amygdala-hippocampal volume and the most widespread shape abnormalities. Using clinical diagnosis, probands with schizophrenia and schizoaffective disorder showed the most significant reductions of amygdala and hippocampal volumes and the most abnormal hippocampal shape compared with healthy controls. Biotype classification provided the strongest neuroanatomical differences compared with conventional DSM diagnoses, with the best discrimination seen using bilateral amygdala and right hippocampal volumes in B-1.

CONCLUSION

These findings characterize amygdala and hippocampal volumetric and shape abnormalities across the psychosis spectrum. Grouping individuals by Biotype showed greater between-group discrimination, suggesting a promising approach and a favorable target for characterizing biological heterogeneity across the psychosis spectrum.

Altered cerebral perfusion in bipolar disorder: A pCASL MRI study

BACKGROUND

Neurovascular abnormalities are relevant to the pathophysiology of bipolar disorder (BD), which can be assessed using cerebral blood flow (CBF) imaging. CBF alterations have been identified in BD, but studies to date have been small and inconclusive. We aimed to determine cortical gray matter CBF (GM-CBF) differences between BD and healthy controls (HC) and to identify relationships between CBF and clinical or cognitive measures.

METHODS

Cortical GM-CBF maps were generated using Pseudo-Continuous Arterial Spin Labeling (pCASL) for 109 participants (BD, n = 61; HC, n = 48). We used SnPM13 to perform non-parametric voxel-wise two-sample t-tests comparing CBF between groups. We performed multiple linear regression to relate GM-CBF with clinical and cognitive measures. Analysis was adjusted for multiple comparisons with 10,000 permutations. Significance was set at a voxel level threshold of P < .001 followed by AlphaSim cluster-wise correction of P < .05.

RESULTS

Compared to HCs, BD patients had greater GM-CBF in the left lateral occipital cortex, superior division and lower CBF in the right lateral occipital, angular and middle temporal gyrus. Greater GM-CBF in the left lateral occipital cortex correlated with worse working memory, verbal memory, attention and speed of processing. We found using voxel-wise regression that decreased gray matter CBF in the bilateral thalamus and cerebellum, and increased right fronto-limbic CBF were associated with worse working memory. No clusters were associated with clinical variables after FDR correction.

CONCLUSIONS

Cortical GM-CBF alterations are seen in BD and may be related to cognitive function, which suggest neurovascular unit dysfunction as a possible pathophysiologic mechanism.

White matter abnormalities across the lifespan of schizophrenia: a harmonized multi-site diffusion MRI study

Several prominent theories of schizophrenia suggest that structural white matter pathologies may follow a developmental, maturational, and/or degenerative process. However, a lack of lifespan studies has precluded verification of these theories. Here, we analyze the largest sample of carefully harmonized diffusion MRI data to comprehensively characterize age-related white matter trajectories, as measured by fractional anisotropy (FA), across the course of schizophrenia. Our analysis comprises diffusion scans of 600 schizophrenia patients and 492 healthy controls at different illness stages and ages (14-65 years), which were gathered from 13 sites. We determined the pattern of age-related FA changes by cross-sectionally assessing the timing of the structural neuropathology associated with schizophrenia. Quadratic curves were used to model between-group FA differences across whole-brain white matter and fiber tracts at each age; fiber tracts were then clustered according to both the effect-sizes and pattern of lifespan white matter FA differences. In whole-brain white matter, FA was significantly lower across the lifespan (up to 7%; p < 0.0033) and reached peak maturation younger in patients (27 years) compared to controls (33 years). Additionally, three distinct patterns of neuropathology emerged when investigating white matter fiber tracts in patients: (1) developmental abnormalities in limbic fibers, (2) accelerated aging and abnormal maturation in long-range association fibers, (3) severe developmental abnormalities and accelerated aging in callosal fibers. Our findings strongly suggest that white matter in schizophrenia is affected across entire stages of the disease. Perhaps most strikingly, we show that white matter changes in schizophrenia involve dynamic interactions between neuropathological processes in a tract-specific manner.

Investigating Sexual Dimorphism of Human White Matter in a Harmonized, Multisite Diffusion Magnetic Resonance Imaging Study

Axonal myelination and repair, critical processes for brain development, maturation, and aging, remain controlled by sexual hormones. Whether this influence is reflected in structural brain differences between sexes, and whether it can be quantified by neuroimaging, remains controversial. Diffusion-weighted magnetic resonance imaging (dMRI) is an in vivo method that can track myelination changes throughout the lifespan. We utilize a large, multisite sample of harmonized dMRI data (n = 551, age = 9-65 years, 46% females/54% males) to investigate the influence of sex on white matter (WM) structure. We model lifespan trajectories of WM using the most common dMRI measure fractional anisotropy (FA). Next, we examine the influence of both age and sex on FA variability. We estimate the overlap between male and female FA and test whether it is possible to label individual brains as male or female. Our results demonstrate regionally and spatially specific effects of sex. Sex differences are limited to limbic structures and young ages. Additionally, not only do sex differences diminish with age, but tracts within each subject become more similar to one another. Last, we show the high overlap in FA between sexes, which implies that determining sex based on WM remains open.

The report of the joint WPA/CINP workgroup on the use and usefulness of antipsychotic medication in the treatment of schizophrenia

This is a report of a joint World Psychiatric Association/International College of Neuropsychopharmacology (WPA/CINP) workgroup concerning the risk/benefit ratio of antipsychotics in the treatment of schizophrenia. It utilized a selective but, within topic, comprehensive review of the literature, taking into consideration all the recently discussed arguments on the matter and avoiding taking sides when the results in the literature were equivocal. The workgroup's conclusions suggested that antipsychotics are efficacious both during the acute and the maintenance phase, and that the current data do not support the existence of a supersensitivity rebound psychosis. Long-term treated patients have better overall outcome and lower mortality than those not taking antipsychotics. Longer duration of untreated psychosis and relapses are modestly related to worse outcome. Loss of brain volume is evident already at first episode and concerns loss of neuropil volume rather than cell loss. Progression of volume loss probably happens in a subgroup of patients with worse prognosis. In humans, antipsychotic treatment neither causes nor worsens volume loss, while there are some data in favor for a protective effect. Schizophrenia manifests 2 to 3 times higher mortality vs the general population, and treatment with antipsychotics includes a number of dangers, including tardive dyskinesia and metabolic syndrome; however, antipsychotic treatment is related to lower mortality, including cardiovascular mortality. In conclusion, the literature strongly supports the use of antipsychotics both during the acute and the maintenance phase without suggesting that it is wise to discontinue antipsychotics after a certain period of time. Antipsychotic treatment improves long-term outcomes and lowers overall and specific-cause mortality.

Abnormal perfusion fluctuation and perfusion connectivity in bipolar disorder measured by dynamic arterial spin labeling

OBJECTIVES

We sought to evaluate whether dynamic Arterial Spin Labeling (dASL), a novel quantitative technique robust to artifacts and noise that especially arise in inferior brain regions, could characterize neural substrates of BD pathology and symptoms.

METHODS

Forty-five subjects (19 BD patients, 26 controls) were imaged using a dASL sequence. Maps of average perfusion, perfusion fluctuation, and perfusion connectivity with anterior cingulate cortex (ACC) were derived. Patient symptoms were quantified along four symptom dimensions determined using factor analysis of the subjects from the Bipolar and Schizophrenia Network on Intermediate Phenotypes (BSNIP) study. Maps of the perfusion measures were compared between BD patients and controls and correlated with the symptom dimensions in the BD patients only by voxel-level and region-level analyses.

RESULTS

BD patients exhibited (i) significantly increased perfusion fluctuations in the left fusiform and inferior temporal regions (P = .020, voxel-level corrected) and marginally increased perfusion fluctuations in the right temporal pole and inferior temporal regions (P = .063, cluster-level corrected), (ii) significantly increased perfusion connectivity between ACC and the occipitoparietal cortex (P = .050, cluster-level corrected). In BD patients, positive symptoms were negatively associated with ACC perfusion connectivity to the right orbitofrontal and superior frontal regions (P = .002, cluster-level corrected) and right orbitofrontal and inferior frontal regions (P = .023, cluster-level corrected).

CONCLUSION

The abnormal perfusion fluctuations and connectivity alterations may underlie the mood fluctuations and cognitive and emotional dysregulation that characterize BD.

Retinal layer abnormalities and their association with clinical and brain measures in psychotic disorders: A preliminary study

Studies utilizing optical coherence tomography (OCT) in psychosis have identified abnormalities in retinal cytoarchitecture. We aim to analyze retinal layer topography in psychosis and its correlation with clinical and imaging parameters. Macular retinal images were obtained via OCT in psychosis probands (n = 25) and healthy controls (HC, n = 15). Clinical, cognitive and structural MRI data were collected from participants. No thinning was noted for the retinal nerve fiber, ganglion cell or inner plexiform layers. We found significant thinning in the right inner temporal, right central, and left inner superior quadrants of the outer nuclear layer (ONL) in probands compared to HC. Thickening of the outer plexiform layer (OPL) was observed in the right inner temporal, left inner superior, and left inner temporal quadrants. The right inner temporal and left inner superior quadrants of both the OPL and ONL showed significant inverse correlations. Retinal pigment epithelium thinning correlated with worse mania symptoms, and thinning in the ONL was associated with worse cognitive function. ONL thinning was also associated with smaller total brain and white matter volume. Our findings suggest that outer retinal layers may provide additional insights into the pathophysiology of psychosis, possibly reflecting synaptic or inflammatory aberrations that lead to retinal pathologies.

O3.4. PSYCHOSIS PHENOTYPES FROM B-SNIP FOR CLINICAL ADVANCES: BIOTYPE CHARACTERISTICS AND TARGETS

Background

Psychiatry aspires to disease understanding and precision medicine. Biological research supporting such missions in psychosis may be compromised by continued reliance on clinical phenomenology in the search for pathophysiological mechanisms. A transdiagnostic deep phenotyping approach, such as that used by the Bipolar-Schizophrenia Network for Intermediate Phenotypes (B-SNIP), offers a promising strategy for discovery of biological mechanisms underlying psychosis syndromes. The B-SNIP consortium has identified biological subtypes of psychosis, Biotypes, which outperform conventional DSM diagnoses when accounting for variance of multiple external validating measures. While these biological distinctions are scientifically remarkable, their resulting clinical manifestations and potential utility in clinical practice is of paramount importance.

Methods

Approximately 1500 psychosis cases and 450 healthy persons were administered the B-SNIP biomarker battery (including MRI, EEG, ocular motor, and cognition measures). Psychosis cases were also clinically characterized using multiple measures, including MADRS, PANSS, YMRS, and Birchwood. Numerical taxonomy approaches were used for identifying biologically homogenous psychosis subgroups (gap and TWO-STEP cluster identifications, k-means clustering, and canonical discriminant analysis). ANOVA models were used to analyze external validating measures. Multivariate discriminant models were used to identify clinical features differentiating conventional psychosis syndromes and psychosis Biotypes.

Results

There was remarkable similarity between previously published biomarker profiles for DSM psychosis syndromes and a new sample of psychosis cases (average r=.92). Numerical taxonomy on biomarker data recovered three subgroups (replicating previous findings), and the biomarker profiles were highly similar to previous results (average r=.87). Schizoaffective cases were both the most diverse and the most clearly differentiated from schizophrenia and bipolar cases (on conative negative symptoms, depression, and mania) in clinical feature space. The only feature that uniquely distinguished schizophrenia was social-relational negative symptoms. Biotype-1 was characterized by accentuations on clinical features consistent with their biomarker deviations (relational negative symptoms, poor social functioning, and dysfunction of cognition). Alternatively, Biotype-2, also consistent with their biomarker deviations, had clinical features indicating neurophysiological dysregulation (most specifically physiological and behavioral dysregulation). Biotype-3 cases, the most normal across biomarkers, were noticeably absent of Biotype-1 clinical features and had more restricted clinical manifestations than any other Biotype or DSM subgroup. We illustrate three possible Biotype-specific treatment targets.

Discussion

Replication of B-SNIP psychosis Biotypes indicates the possible utility and importance of neurobiological subtyping within psychosis that can yield specific treatment targets. In an analysis of clinical features, B-SNIP found that Biotypes have unique and defining clinical features that are consistent with their neurobiological profiles. Biotypes and DSM psychosis subgroups are neither neurobiologically nor clinically redundant. Specific treatment targets for psychosis Biotypes are not derivable from conventional clinical psychosis diagnoses. B-SNIP outcomes provide a background for future work that could establish psychiatry as a laboratory discipline, at least with regard to care of psychosis patients. This path is hypothetical at the moment but aspirational for the field.

Molecular adaptations of the blood-brain barrier promote stress resilience vs. depression

Preclinical and clinical studies suggest that inflammation and vascular dysfunction contribute to the pathogenesis of major depressive disorder (MDD). Chronic social stress alters blood-brain barrier (BBB) integrity through loss of tight junction protein claudin-5 (cldn5) in male mice, promoting passage of circulating proinflammatory cytokines and depression-like behaviors. This effect is prominent within the nucleus accumbens, a brain region associated with mood regulation; however, the mechanisms involved are unclear. Moreover, compensatory responses leading to proper behavioral strategies and active resilience are unknown. Here we identify active molecular changes within the BBB associated with stress resilience that might serve a protective role for the neurovasculature. We also confirm the relevance of such changes to human depression and antidepressant treatment. We show that permissive epigenetic regulation of cldn5 expression and low endothelium expression of repressive cldn5-related transcription factor foxo1 are associated with stress resilience. Region- and endothelial cell-specific whole transcriptomic analyses revealed molecular signatures associated with stress vulnerability vs. resilience. We identified proinflammatory TNFα/NFκB signaling and hdac1 as mediators of stress susceptibility. Pharmacological inhibition of stress-induced increase in hdac1 activity rescued cldn5 expression in the NAc and promoted resilience. Importantly, we confirmed changes in HDAC1 expression in the NAc of depressed patients without antidepressant treatment in line with CLDN5 loss. Conversely, many of these deleterious CLDN5-related molecular changes were reduced in postmortem NAc from antidepressant-treated subjects. These findings reinforce the importance of considering stress-induced neurovascular pathology in depression and provide therapeutic targets to treat this mood disorder and promote resilience.

NRXN1 is associated with enlargement of the temporal horns of the lateral ventricles in psychosis

Schizophrenia, Schizoaffective, and Bipolar disorders share behavioral and phenomenological traits, intermediate phenotypes, and some associated genetic loci with pleiotropic effects. Volumetric abnormalities in brain structures are among the intermediate phenotypes consistently reported associated with these disorders. In order to examine the genetic underpinnings of these structural brain modifications, we performed genome-wide association analyses (GWAS) on 60 quantitative structural brain MRI phenotypes in a sample of 777 subjects (483 cases and 294 controls pooled together). Genotyping was performed with the Illumina PsychChip microarray, followed by imputation to the 1000 genomes multiethnic reference panel. Enlargement of the Temporal Horns of Lateral Ventricles (THLV) is associated with an intronic SNP of the gene NRXN1 (rs12467877, P = 6.76E-10), which accounts for 4.5% of the variance in size. Enlarged THLV is associated with psychosis in this sample, and with reduction of the hippocampus and enlargement of the choroid plexus and caudate. Eight other suggestively significant associations (P < 5.5E-8) were identified with THLV and 5 other brain structures. Although rare deletions of NRXN1 have been previously associated with psychosis, this is the first report of a common SNP variant of NRXN1 associated with enlargement of the THLV in psychosis.

Common Data Elements for National Institute of Mental Health-Funded Translational Early Psychosis Research

The National Institutes of Health has established the PhenX Toolkit as a web-based resource containing consensus measures freely available to the research community. The National Institute of Mental Health (NIMH) has introduced the Mental Health Research Core Collection as part of the PhenX Toolkit and recently convened the PhenX Early Psychosis Working Group to generate the PhenX Early Psychosis Specialty Collection. The Working Group consisted of two complementary panels for clinical and translational research. We review the process, deliberations, and products of the translational research panel. The Early Psychosis Specialty Collection rationale for measure selection as well as additional information and protocols for obtaining each measure are available on the PhenX website (https://www.phenxtoolkit.org). The NIMH strongly encourages investigators to use instruments from the PhenX Mental Health Research Collections in NIMH-funded studies and discourages use of alternative measures to collect similar data without justification. We also discuss some of the potential advances that can be achieved by collecting common data elements across large-scale longitudinal studies of early psychosis.

Association of Choroid Plexus Enlargement With Cognitive, Inflammatory, and Structural Phenotypes Across the Psychosis Spectrum

OBJECTIVE

The choroid plexus is an important physiological barrier and produces CSF and neurotrophic, angiogenic, and inflammatory factors involved in brain development. Choroid plexus abnormalities have been implicated in both schizophrenia and bipolar disorder. A previous choroid plexus transcriptomic analysis of schizophrenia identified an upregulation of immune and inflammatory genes that correlated with peripheral inflammatory markers. The purpose of this study was to examine choroid plexus volume in probands across the psychosis spectrum and in their first-degree and axis II cluster A relatives, as well as choroid plexus familiality and choroid plexus covariance with clinical, cognitive, brain, and peripheral marker measures.

METHODS

Choroid plexus volume was quantified (using FreeSurfer) in psychosis probands, their first-degree and axis II cluster A relatives, and healthy control subjects, organized by DSM-IV-TR diagnosis. Analyte, structural connectivity, and genotype data were collected from a subset of study subjects.

RESULTS

Choroid plexus volume was significantly larger in probands compared with first-degree relatives or healthy control subjects; first-degree relatives had intermediate enlargement compared with healthy control subjects; and total choroid plexus volume was significantly heritable. Larger volume was associated with worse cognition, smaller total gray matter and amygdala volume, larger lateral ventricle volume, and lower structural connectivity in probands. Associations between larger volume and higher levels of interleukin 6 in probands was also observed.

CONCLUSIONS

These findings suggest the involvement of the choroid plexus across the psychosis spectrum with a potential pathophysiological mechanism involving the neuroimmune axis, which functions in maintaining brain homeostasis and interacting with the peripheral immune and inflammatory system. The choroid plexus may be an important target in future research.

VEGFA GENE variation influences hallucinations and frontotemporal morphology in psychotic disorders: a B-SNIP study

Vascular endothelial growth factor A (VEGFA) dysfunction may contribute to a number of pathological processes that characterize psychotic disorders. However, the influence of VEGFA gene variants on clinical and neuroimaging phenotypes in psychotic disorders has yet to be shown. In the present study, we examined whether different VEGFA gene variants influence psychosis risk, symptom severity, cognition, and brain volume. The study group included 480 probands (Bipolar I disorder with psychosis, n = 205; Schizoaffective disorder, n = 112; Schizophrenia, n = 163) and 126 healthy controls that were recruited across six sites in the B-SNIP consortium. VEGFA variants identified for analysis (rs699947, rs833070, and rs2146323) were quantified via SNP chip array. We assessed symptoms and cognition using standardized clinical and neuropsychological batteries. The dorsolateral prefrontal cortex (DLPFC), medial temporal lobe, and hippocampal volumes were quantified using FreeSurfer. In our sample, VEGFA rs2146323 A- carriers showed reduced odds of being a proband (p = 0.037, OR = 0.65, 95% CI = 0.43-0.98) compared to noncarriers, but not for rs699947 or rs833070. In probands, rs2146323 A- carriers demonstrated fewer hallucinations (p = 0.035, Cohen's d = 0.194), as well as significantly greater DLPFC (p < 0.05, Cohen's d = -0.21) and parahippocampal volumes (p < 0.01, Cohen's d = -0.27). No clinical or neuroimaging associations were identified for rs699947 or rs833070. In general, we found that the three SNPs exhibited several significant negative relationships between psychosis symptoms and brain structure. In the probands and control groups, positive relationships were identified between several cognitive and brain volume measures. The findings suggest VEGFA effects in the DLPFC and hippocampus found in animals may also extend to humans. VEGFA variations may have important implications in identifying dimensional moderators of function that could be targeted through VEGFA-mediated interventions.

Racial disparities in bipolar disorder treatment and research: a call to action

OBJECTIVES

Health disparities between individuals of African and European ancestry are well documented. The disparities in bipolar disorder may be driven by racial bias superimposed on established factors contributing to misdiagnosis, including: evolving empirically based diagnostic criteria (International Classification of Diseases [ICD], Research Diagnostic Criteria [RDC] and Diagnostic and Statistical Manual [DSM]), multiple symptom domains (i.e. mania, depression and psychosis), and multimodal medical and additional psychiatric comorbidity.

METHODS

For this paper, we reviewed the phenomenological differences between bipolar individuals of African and European ancestry in the context of diagnostic criteria and clinical factors that may contribute to a potential racial bias.

RESULTS

Published data show that bipolar persons of African ancestry, compared with bipolar persons of non-African ancestry, are more often misdiagnosed with a disease other than bipolar disorder (i.e. schizophrenia). Additionally, studies show that there are disparities in recruiting patients of African ancestry to participate in important genomic studies. This gap in biological research in this underrepresented minority may represent a missed opportunity to address potential racial differences in the risk and course of bipolar illness.

CONCLUSION

A concerted effort by the research community to increase inclusion of diverse persons in studies of bipolar disorder through community engagement may facilitate fully addressing these diagnostic and treatment disparities in bipolar individuals of African ancestry.

Genetic analysis of deep phenotyping projects in common disorders

Several studies of complex psychotic disorders with large numbers of neurobiological phenotypes are currently under way, in living patients and controls, and on assemblies of brain specimens. Genetic analyses of such data typically present challenges, because of the choice of underlying hypotheses on genetic architecture of the studied disorders and phenotypes, large numbers of phenotypes, the appropriate multiple testing corrections, limited numbers of subjects, imputations required on missing phenotypes and genotypes, and the cross-disciplinary nature of the phenotype measures. Advances in genotype and phenotype imputation, and in genome-wide association (GWAS) methods, are useful in dealing with these challenges. As compared with the more traditional single-trait analyses, deep phenotyping with simultaneous genome-wide analyses serves as a discovery tool for previously unsuspected relationships of phenotypic traits with each other, and with specific molecular involvements.

The association between mood state and chronobiological characteristics in bipolar I disorder: a naturalistic, variable cluster analysis-based study

BACKGROUND

Multiple types of chronobiological disturbances have been reported in bipolar disorder, including characteristics associated with general activity levels, sleep, and rhythmicity. Previous studies have focused on examining the individual relationships between affective state and chronobiological characteristics. The aim of this study was to conduct a variable cluster analysis in order to ascertain how mood states are associated with chronobiological traits in bipolar I disorder (BDI). We hypothesized that manic symptomatology would be associated with disturbances of rhythm.

RESULTS

Variable cluster analysis identified five chronobiological clusters in 105 BDI subjects. Cluster 1, comprising subjective sleep quality was associated with both mania and depression. Cluster 2, which comprised variables describing the degree of rhythmicity, was associated with mania. Significant associations between mood state and cluster analysis-identified chronobiological variables were noted. Disturbances of mood were associated with subjectively assessed sleep disturbances as opposed to objectively determined, actigraphy-based sleep variables. No associations with general activity variables were noted. Relationships between gender and medication classes in use and cluster analysis-identified chronobiological characteristics were noted. Exploratory analyses noted that medication class had a larger impact on these relationships than the number of psychiatric medications in use.

CONCLUSIONS

In a BDI sample, variable cluster analysis was able to group related chronobiological variables. The results support our primary hypothesis that mood state, particularly mania, is associated with chronobiological disturbances. Further research is required in order to define these relationships and to determine the directionality of the associations between mood state and chronobiological characteristics.

Autism BrainNet: A network of postmortem brain banks established to facilitate autism research

Autism spectrum disorder (ASD or autism) is a neurodevelopmental condition that affects over 1% of the population worldwide. Developing effective preventions and treatments for autism will depend on understanding the genetic perturbations and underlying neuropathology of the disorder. While evidence from magnetic resonance imaging and other noninvasive techniques points to altered development and organization of the autistic brain, these tools lack the resolution for identifying the cellular and molecular underpinnings of the disorder. Postmortem studies of high-quality human brain tissue currently represent the only viable option to pursuing these types of studies. However, the availability of high-quality ASD brain tissue has been extremely limited. Here we describe the establishment of a privately funded tissue bank, Autism BrainNet, a network of brain collection sites that work in a coordinated fashion to develop an adequate library of human postmortem brain tissues. Autism BrainNet was initiated as a collaboration between the Simons Foundation and Autism Speaks, and is currently funded by the Simons Foundation Autism Research Initiative. Autism BrainNet has collection sites (nodes) in California, Texas, New York, and Massachusetts; an affiliated, international node is located in Oxford, England. All donations to this network become part of a consolidated pool of tissue that is distributed to qualified investigators worldwide to carry out autism research. An essential component of this program is a widespread outreach program that highlights the need for postmortem brain donations to families affected by autism, led by the Autism Science Foundation. Challenges include an outreach campaign that deals with a disorder beginning in early childhood, collecting an adequate number of donations to deal with the high level of biologic heterogeneity of autism, and preparing this limited resource for optimal distribution to the greatest number of investigators.

Social stress induces neurovascular pathology promoting depression

Studies suggest that heightened peripheral inflammation contributes to the pathogenesis of major depressive disorder. We investigated the effect of chronic social defeat stress, a mouse model of depression, on blood-brain barrier (BBB) permeability and infiltration of peripheral immune signals. We found reduced expression of the endothelial cell tight junction protein claudin-5 (Cldn5) and abnormal blood vessel morphology in nucleus accumbens (NAc) of stress-susceptible but not resilient mice. CLDN5 expression was also decreased in NAc of depressed patients. Cldn5 downregulation was sufficient to induce depression-like behaviors following subthreshold social stress whereas chronic antidepressant treatment rescued Cldn5 loss and promoted resilience. Reduced BBB integrity in NAc of stress-susceptible or mice injected with adeno-associated virus expressing shRNA against Cldn5 caused infiltration of the peripheral cytokine interleukin-6 (IL-6) into brain parenchyma and subsequent expression of depression-like behaviors. These findings suggest that chronic social stress alters BBB integrity through loss of tight junction protein Cldn5, promoting peripheral IL-6 passage across the BBB and depression.

Sex-specific transcriptional signatures in human depression

Major depressive disorder (MDD) is a leading cause of disease burden worldwide. While the incidence, symptoms and treatment of MDD all point toward major sex differences, the molecular mechanisms underlying this sexual dimorphism remain largely unknown. Here, combining differential expression and gene coexpression network analyses, we provide a comprehensive characterization of male and female transcriptional profiles associated with MDD across six brain regions. We overlap our human profiles with those from a mouse model, chronic variable stress, and capitalize on converging pathways to define molecular and physiological mechanisms underlying the expression of stress susceptibility in males and females. Our results show a major rearrangement of transcriptional patterns in MDD, with limited overlap between males and females, an effect seen in both depressed humans and stressed mice. We identify key regulators of sex-specific gene networks underlying MDD and confirm their sex-specific impact as mediators of stress susceptibility. For example, downregulation of the female-specific hub gene Dusp6 in mouse prefrontal cortex mimicked stress susceptibility in females, but not males, by increasing ERK signaling and pyramidal neuron excitability. Such Dusp6 downregulation also recapitulated the transcriptional remodeling that occurs in prefrontal cortex of depressed females. Together our findings reveal marked sexual dimorphism at the transcriptional level in MDD and highlight the importance of studying sex-specific treatments for this disorder.

Neural complexity as a potential translational biomarker for psychosis

BACKGROUND

The adaptability of the human brain to the constantly changing environment is reduced in patients with psychotic disorders, leading to impaired cognitive functions. Brain signal complexity, which may reflect adaptability, can be readily quantified via resting-state functional magnetic resonance imaging (fMRI) signals. We hypothesized that resting-state brain signal complexity is altered in psychotic disorders, and is correlated with cognitive impairment.

METHODS

We assessed 156 healthy controls (HC) and 330 probands, including 125 patients with psychotic bipolar disorder (BP), 107 patients with schizophrenia (SZ), 98 patients with schizoaffective disorder (SAD) and 230 of their unaffected first-degree relatives (76 BPR, 79 SADR, and 75 SZR) from four sites of the Bipolar-Schizophrenia Network on Intermediate Phenotypes (B-SNIP) consortium. Using multi-scale entropy analysis, we determined whether patients and/or relatives had pathologic differences in complexity of resting-state fMRI signals toward regularity (reduced entropy in all time scales), or toward uncorrelated randomness (increased entropy in fine time scales that decays as the time scale increases) and how these complexity differences might be associated with cognitive impairment.

RESULTS

Compared to HC subjects, proband groups showed either decreased complexity toward regularity or toward randomness. SZ probands showed decreased complexity toward regular signal in hypothalamus, and BP probands in left inferior occipital, right precentral and left superior parietal regions, whereas no brain region with decreased complexity toward regularity was found in SAD probands. All proband groups showed significantly increased brain signal randomness in dorsal and ventral prefrontal cortex (PFC), and unaffected relatives showed no complexity differences in PFC regions. SZ had the largest area of involvement in both dorsal and ventral PFC. BP and SAD probands shared increased brain signal randomness in ventral medial PFC, BP and SZ probands shared increased brain signal randomness in ventral lateral PFC, whereas SAD and SZ probands shared increased brain signal randomness in dorsal medial PFC. Only SZ showed increased brain signal randomness in dorsal lateral PFC. The increased brain signal randomness in dorsal or ventral PFC was weakly associated with reduced cognitive performance in psychotic probands.

CONCLUSION

These observations support the loss of brain complexity hypothesis in psychotic probands. Furthermore, we found significant differences as well as overlaps of pathologic brain signal complexity between psychotic probands by DSM diagnoses, thus suggesting a biological approach to categorizing psychosis based on functional neuroimaging data.

Novel gene-brain structure relationships in psychotic disorder revealed using parallel independent component analyses

BACKGROUND

Schizophrenia, schizoaffective disorder, and psychotic bipolar disorder overlap with regard to symptoms, structural and functional brain abnormalities, and genetic risk factors. Neurobiological pathways connecting genes to clinical phenotypes across the spectrum from schizophrenia to psychotic bipolar disorder remain largely unknown.

METHODS

We examined the relationship between structural brain changes and risk alleles across the psychosis spectrum in the multi-site Bipolar-Schizophrenia Network for Intermediate Phenotypes (B-SNIP) cohort. Regional MRI brain volumes were examined in 389 subjects with a psychotic disorder (139 schizophrenia, 90 schizoaffective disorder, and 160 psychotic bipolar disorder) and 123 healthy controls. 451,701 single-nucleotide polymorphisms were screened and processed using parallel independent component analysis (para-ICA) to assess associations between genes and structural brain abnormalities in probands.

RESULTS

482 subjects were included after quality control (364 individuals with psychotic disorder and 118 healthy controls). Para-ICA identified four genetic components including several risk genes already known to contribute to schizophrenia and bipolar disorder and revealed three structural components that showed overlapping relationships with the disease risk genes across the three psychotic disorders. Functional ontologies representing these gene clusters included physiological pathways involved in brain development, synaptic transmission, and ion channel activity.

CONCLUSIONS

Heritable brain structural findings such as reduced cortical thickness and surface area in probands across the psychosis spectrum were associated with somewhat distinct genes related to putative disease pathways implicated in psychotic disorders. This suggests that brain structural alterations might represent discrete psychosis intermediate phenotypes along common neurobiological pathways underlying disease expression across the psychosis spectrum.

Diverse Non-genetic, Allele-Specific Expression Effects Shape Genetic Architecture at the Cellular Level in the Mammalian Brain

Interactions between genetic and epigenetic effects shape brain function, behavior, and the risk for mental illness. Random X inactivation and genomic imprinting are epigenetic allelic effects that are well known to influence genetic architecture and disease risk. Less is known about the nature, prevalence, and conservation of other potential epigenetic allelic effects in vivo in the mouse and primate brain. Here we devise genomics, in situ hybridization, and mouse genetics strategies to uncover diverse allelic effects in the brain that are not caused by imprinting or genetic variation. We found allelic effects that are developmental stage and cell type specific, that are prevalent in the neonatal brain, and that cause mosaics of monoallelic brain cells that differentially express wild-type and mutant alleles for heterozygous mutations. Finally, we show that diverse non-genetic allelic effects that impact mental illness risk genes exist in the macaque and human brain. Our findings have potential implications for mammalian brain genetics. VIDEO ABSTRACT.

Amygdala Hyperactivity at Rest in Paranoid Individuals With Schizophrenia

OBJECTIVE

The amygdala's role in threat perception suggests that increased activation of this region may be related to paranoid ideation. However, investigations of amygdala function in paranoid individuals with schizophrenia, compared with both healthy individuals and nonparanoid individuals with schizophrenia, have consistently reported reduced task-related activation. The reliance of blood-oxygen-level-dependent functional MRI on a contrast between events and baseline, and the inability to quantitatively measure this baseline, may account for these counterintuitive findings. The present study tested for differences in baseline levels of amygdala activity in paranoid and nonparanoid individuals with schizophrenia using arterial spin labeling perfusion MRI.

METHOD

Resting cerebral blood flow (CBF) and task-related activation of the amygdala were measured in 25 healthy individuals, 16 individuals with schizophrenia who were actively paranoid at the time of scanning, and 16 individuals with schizophrenia who were not paranoid.

RESULTS

Analysis of relative CBF values extracted from the amygdala bilaterally revealed significantly increased activity in the left amygdala in paranoid patient volunteers compared with healthy comparison subjects and nonparanoid patient volunteers. Increased CBF was also evident in the right amygdala but did not reach the level of statistical significance. Paranoid volunteers also showed significantly decreased task-related activation of the amygdala compared with the two other groups.

CONCLUSIONS

These findings suggest that amygdala hyperactivation may underlie paranoia in schizophrenia. Additionally, the reported differences between paranoid and nonparanoid patient volunteers emphasize the importance of considering symptom-based subgroups and baseline levels of activity in future investigations of neural activation in schizophrenia.

Increased cardiometabolic dysfunction in first-degree relatives of patients with psychotic disorders

INTRODUCTION

Elevated prevalence of comorbid cardio-vascular and metabolic dysfunction (CMD) is consistently reported in patients with severe psychotic disorders such as schizophrenia (SZ), schizoaffective (SZA) and bipolar disorder (BP-P). Since both psychosis and CMD are substantively heritable in nature, we attempted to investigate the occurrence of CMD disorders in first-degree relatives of probands with psychosis.

METHODS

Our sample included 861 probands with a diagnosis of SZ (n=354), SZA (n=212) and BP-P (n=295), 776 first-degree relatives of probands and 416 healthy controls. Logistic regression was used to compare prevalence of any CMD disorders (diabetes, hypertension, hyperlipidemia or coronary artery disease) across groups. Post hoc tests of independence checked for CMD prevalence across psychosis diagnosis (SZ, SZA and BP-P), both in relatives of probands and within probands themselves.

RESULTS

After controlling for potential confounders, first-degree relatives with (p<0.001) and without (p=0.03) Axis I non-psychotic or Axis- II cluster disorders were at a significant risk for CMD compared to controls. No significant difference (p=0.42) was observed in prevalence of CMD between relatives of SZ, SZA and BP-P, or between psychosis diagnoses for probands (p=0.25).

DISCUSSION

Prevalence of CMD was increased in the first-degree relatives of psychosis subjects. This finding suggests the possibility of overlapping genetic contributions to CMD and psychosis. Increased somatic disease burden in relatives of psychotic disorder probands points to need for early detection and preventive efforts in this population.

Conserved higher-order chromatin regulates NMDA receptor gene expression and cognition

Three-dimensional chromosomal conformations regulate transcription by moving enhancers and regulatory elements into spatial proximity with target genes. Here we describe activity-regulated long-range loopings bypassing up to 0.5 Mb of linear genome to modulate NMDA glutamate receptor GRIN2B expression in human and mouse prefrontal cortex. Distal intronic and 3' intergenic loop formations competed with repressor elements to access promoter-proximal sequences, and facilitated expression via a "cargo" of AP-1 and NRF-1 transcription factors and TALE-based transcriptional activators. Neuronal deletion or overexpression of Kmt2a/Mll1 H3K4- and Kmt1e/Setdb1 H3K9-methyltransferase was associated with higher-order chromatin changes at distal regulatory Grin2b sequences and impairments in working memory. Genetic polymorphisms and isogenic deletions of loop-bound sequences conferred liability for cognitive performance and decreased GRIN2B expression. Dynamic regulation of chromosomal conformations emerges as a novel layer for transcriptional mechanisms impacting neuronal signaling and cognition.

β-catenin mediates stress resilience through Dicer1/microRNA regulation

β-catenin is a multi-functional protein that plays an important role in the mature central nervous system; its dysfunction has been implicated in several neuropsychiatric disorders, including depression. Here we show that β-catenin mediates pro-resilient and anxiolytic effects in mice in the nucleus accumbens, a key brain reward region, an effect mediated by D2-type medium spiny neurons. Using genome-wide β-catenin enrichment mapping, we identify Dicer1—important in small RNA (e.g., microRNA) biogenesis—as a β-catenin target gene that mediates resilience. Small RNA profiling after excising β-catenin from nucleus accumbens in the context of chronic stress reveals β-catenin-dependent microRNA regulation associated with resilience. Together, these findings establish β-catenin as a critical regulator in the development of behavioral resilience, activating a network that includes Dicer1 and downstream microRNAs. We thus present a foundation for the development of novel therapeutic targets to promote stress resilience.

Local gyrification index in probands with psychotic disorders and their first-degree relatives

BACKGROUND

Psychotic disorders are characterized by aberrant neural connectivity. Alterations in gyrification, the pattern and degree of cortical folding, may be related to the early development of connectivity. Past gyrification studies have relatively small sample sizes, yield mixed results for schizophrenia, and are scant for psychotic bipolar and schizoaffective (SZA) disorders and for relatives of these conditions. Here, we examine gyrification in psychotic disorder patients and their first-degree relatives as a possible endophenotype.

METHODS

Regional local gyrification index (LGI) values, as measured by FreeSurfer software, were compared between 243 control subjects, 388 psychotic disorder probands, and 300 of their first-degree relatives. For patients, LGI values were examined grouped across psychotic diagnoses and then separately for schizophrenia, SZA, and bipolar disorder. Familiality (heritability) values and correlations with clinical measures were also calculated for regional LGI values.

RESULTS

Probands exhibited significant hypogyria compared with control subjects in three brain regions and relatives with Axis II cluster A disorders showed nearly significant hypogyria in these same regions. Local gyrification index values in these locations were significantly heritable and uncorrelated with any clinical measure. Observations of significant hypogyria were most widespread in SZA.

CONCLUSIONS

Psychotic disorders appear to be characterized by significant regionally localized hypogyria, particularly in cingulate cortex. This abnormality may be a structural endophenotype marking risk for psychotic illness and it may help elucidate etiological underpinnings of psychotic disorders.

An important role for cholecystokinin, a CLOCK target gene, in the development and treatment of manic-like behaviors

Mice with a mutation in the Clock gene (ClockΔ19) have been identified as a model of mania; however, the mechanisms that underlie this phenotype, and the changes in the brain that are necessary for lithium's effectiveness on these mice remain unclear. Here, we find that cholecystokinin (Cck) is a direct transcriptional target of CLOCK and levels of Cck are reduced in the ventral tegmental area (VTA) of ClockΔ19 mice. Selective knockdown of Cck expression via RNA interference in the VTA of wild-type mice produces a manic-like phenotype. Moreover, chronic treatment with lithium restores Cck expression to near wild-type and this increase is necessary for the therapeutic actions of lithium. The decrease in Cck expression in the ClockΔ19 mice appears to be due to a lack of interaction with the histone methyltransferase, MLL1, resulting in decreased histone H3K4me3 and gene transcription, an effect reversed by lithium. Human postmortem tissue from bipolar subjects reveals a similar increase in Cck expression in the VTA with mood stabilizer treatment. These studies identify a key role for Cck in the development and treatment of mania, and describe some of the molecular mechanisms by which lithium may act as an effective antimanic agent.

A randomized, placebo-controlled proof-of-concept, crossover trial of phenytoin for hydrocortisone-induced declarative memory changes

BACKGROUND

Corticosteroid excess is associated with declarative memory impairment and hippocampal atrophy. These findings are clinically important because approximately 1% of the population receives prescription corticosteroids at any time, and major depressive disorder is associated with elevated cortisol levels and hippocampal atrophy. In animals, hippocampal changes with corticosteroids are blocked by phenytoin. The objective of the current study was to extend these preclinical findings to humans. We examined whether phenytoin attenuated the effects of hydrocortisone on declarative memory. Functional magnetic resonance imaging (fMRI) assessed task-related hippocampal activation.

METHODS

A randomized, double-blind, placebo-controlled, within-subject crossover study was conducted in 17 healthy adult volunteers. Participants received hydrocortisone (2.5 days), phenytoin (3.5 days), both medications together, or placebo, with 21-day washouts between conditions. Differences between treatments were estimated using a mixed-effects repeated measures analysis.

RESULTS

Fifteen participants had data from at least two treatment conditions and were used in the analysis. Basal cortisol levels negatively correlated with fMRI BOLD activation in the para-hippocampus with a similar trend observed in the hippocampus. Decrease in declarative memory with hydrocortisone was blocked with concomitant phenytoin administration. Relative to the placebo condition, a significant decrease in hippocampal BOLD activation was observed with hydrocortisone and phenytoin alone, and the two medications in combination. Declarative memory did not show significant correlations with hippocampal activation.

LIMITATIONS

The modest sample size, which limited our statistical power, was a limitation.

CONCLUSIONS

Findings from this pilot study suggest phenytoin attenuated effects of corticosteroids memory in humans, but potentiated the reduction in hippocampal activation.

Measurement of glycine in gray and white matter in the human brain in vivo by 1H MRS at 7.0 T

The concentration of glycine (Gly) was measured in gray matter (GM) and white matter (WM) in the human brain using single-voxel localized (1)H MRS at 7 T. A point-resolved spectroscopy sequence with echo time = 150 ms was used for measuring Gly levels in various regions of the frontal and occipital lobes in 11 healthy volunteers and one subject with a glioblastoma. The point-resolved spectroscopy spectra were analyzed with LCModel using basis functions generated from density matrix simulations that included the effects of volume localized radio-frequency and gradient pulses. The fraction of GM and white matter within the voxels was obtained from T(1)-weighted image segmentation. The metabolite concentrations within the voxels, estimated with respect to the GM + WM water concentrations, were fitted to a linear function of fractional GM content. The Gly concentrations in pure GM and white matter were estimated to be 1.1 and 0.1 mM, with 95% confidence intervals 1.0-1.2 and 0.0-0.2, respectively.

A dimensional approach to the psychosis spectrum between bipolar disorder and schizophrenia: the Schizo-Bipolar Scale

BACKGROUND

There is increasing evidence for phenomenological, biological and genetic overlap between schizophrenia and bipolar disorder, bringing into question the traditional dichotomy between them. Neurobiological models linked to dimensional clinical data may provide a better foundation to represent diagnostic variation in neuropsychiatric disorders.

METHOD

To capture the interaction between psychosis and affective symptoms dimensionally, we devised a brief descriptive scale based on the type and relative proportions of psychotic and affective symptoms over the illness course. The scale was administered to a series of 762 patients with psychotic disorders, including schizophrenia, schizoaffective and psychotic bipolar disorder assessed as part of the Bipolar-Schizophrenia Network for Intermediate Phenotypes (B-SNIP) study.

RESULTS

The resulting Schizo-Bipolar Scale scores across these disorders showed neither a clear dichotomy nor a simple continuous distribution. While the majority of cases had ratings close to prototypic schizophrenia or bipolar disorder, a large group (45% of cases) fell on the continuum between these two prototypes.

CONCLUSIONS

Our data suggest a hybrid conceptualization model with a representation of cases with prototypic schizophrenia or bipolar disorder at the extremes, but a large group of patients on the continuum between them that traditionally would be considered schizoaffective. A dimensional approach, using the Schizo-Bipolar Scale, characterized patients across a spectrum of psychopathology. This scale may provide a valuable means to examine the relationships between schizophrenia and psychotic bipolar disorder.

A framework on surface-based connectivity quantification for the human brain

Quantifying the connectivity between arbitrary surface patches in the human brain cortex can be used in studies on brain function and to characterize clinical diseases involving abnormal connectivity. Cortical regions of human brain in their natural forms can be represented in surface formats. In this paper, we present a framework to quantify connectivity using cortical surface segmentation and labeling from structural magnetic resonance images, tractography from diffusion tensor images, and nonlinear inter-subject registration. For a single subject, the connectivity intensity of any point on the cortical surface is set to unity if the point is connected and zero if it is not connected. The connectivity proportion is defined as the ratio of the total connected surface area to the total area of the surface patch. By nonlinearly registering the connectivity data of a group of normal controls into a template space, a population connectivity metric can be defined as either the average connectivity intensity of a cortical point or the average connectivity proportion of a cortical region. In the template space, a connectivity profile and a connectivity histogram of an arbitrary cortical region of interest can then be derived from these connectivity quantification values. Results from the application of these quantification metrics to a population of schizophrenia patients and normal controls are presented, revealing connectivity signatures of specified cortical regions and detecting connectivity abnormalities.

Reversal of depressed behaviors in mice by p11 gene therapy in the nucleus accumbens

The etiology of major depression remains unknown, but dysfunction of serotonergic signaling has long been implicated in the pathophysiology of this disorder. p11 is an S100 family member recently identified as a serotonin 1B [5-hydroxytryptamine 1B (5-HT(1B))] and serotonin 4 (5-HT(4)) receptor-binding protein. Mutant mice in which p11 is deleted show depression-like behaviors, suggesting that p11 may be a mediator of affective disorder pathophysiology. Using somatic gene transfer, we have now identified the nucleus accumbens as a key site of p11 action. Reduction of p11 with adeno-associated virus (AAV)-mediated RNA interference in the nucleus accumbens, but not in the anterior cingulate, of normal adult mice resulted in depression-like behaviors nearly identical to those seen in p11 knockout mice. Restoration of p11 expression specifically in the nucleus accumbens of p11 knockout mice normalized depression-like behaviors. Human nucleus accumbens tissue shows a significant reduction of p11 protein in depressed patients when compared to matched healthy controls. These results suggest that p11 loss in rodent and human nucleus accumbens may contribute to the pathophysiology of depression. Normalization of p11 expression within this brain region with AAV-mediated gene therapy may be of therapeutic value.

Learning and generalization in schizophrenia: effects of disease and antipsychotic drug treatment

BACKGROUND

Schizophrenia involves alterations in hippocampal function. The implications of these alterations for memory function in the illness remain poorly understood. Furthermore, it remains unknown how memory is impacted by drug treatments for schizophrenia. The goal of this study was to delineate specific memory processes that are disrupted in schizophrenia and explore how they are affected by medication. We specifically focus on memory generalization--the ability to flexibly generalize memories in novel situations.

METHODS

Individuals with schizophrenia (n = 56) and healthy control subjects (n = 20) were tested on a computerized memory generalization paradigm. Participants first engaged in trial-by-error associative learning. They were then asked to generalize what they learned by responding to novel stimulus combinations. Individuals with schizophrenia were tested on or off antipsychotic medication, using a between-subject design in order to eliminate concerns about learning-set effects.

RESULTS

Individuals with schizophrenia were selectively impaired in their ability to generalize knowledge, despite having intact learning and memory accuracy. This impairment was found only in individuals tested off medication. Individuals tested on medication generalized almost as well as healthy control subjects. This between-group difference was selective to memory generalization.

CONCLUSIONS

These findings suggest that individuals with schizophrenia have a selective alteration in the ability to flexibly generalize past experience toward novel learning environments. This alteration is unaccompanied by global memory impairments. Additionally, the results indicate a robust generalization difference on the basis of medication status. These results suggest that hippocampal abnormalities in schizophrenia might be alleviated with antipsychotic medication, with important implications for understanding adaptive memory-guided behavior.

Localization of NAAG-related gene expression deficits to the anterior hippocampus in schizophrenia

N-acetyl aspartyl glutamate (NAAG) is an endogenous agonist at the metabotropic glutamate receptor 3 (mGluR3,GRM3) receptor and antagonist at the N-methyl d-aspartate (NMDA) receptor, both receptors important to the pathophysiology of schizophrenia. Glutamate carboxypeptidase II (GCPII), an enzyme that metabolizes NAAG, is also implicated in this illness. In this study, we conducted in situ hybridization experiments to examine expression of mGluR3 and GCPII transcripts along the rostrocaudal axis of the human postmortem hippocampus. We hypothesized that we would find changes in mGluR3 and/or GCPII in the AH but not posterior hippocampus (PH) in schizophrenia. We compared mRNA levels of these genes in the dentate gyrus (DG) and cornu ammonis (CA)1 and CA3 of AH and PH in 20 matched pairs of control and schizophrenia cases. In controls, mGluR3 is highly expressed in the DG and at lower levels in CA1 and CA3 while GCP II is expressed at similar levels in these regions. Group comparisons show a significant reduction of GCPII mRNA level in the AH in schizophrenia. Post hoc analyses reveal this difference is localized to the CA1 region. In addition, we find a significant positive correlation between GCPII and mGluR3 mRNA in the CA3 of the control AH (r=0.66, p=0.008) which is not present in schizophrenia (r=0.096, p=0.76). This may reflect a disrupted functional interaction between NAAG and mGluR3 in CA3 in schizophrenia. These data suggest that NAAG-mediated signaling is disrupted in the AH in schizophrenia and localize the defect to the CA1 and CA3 regions.

Divalproex ER combined with olanzapine or risperidone for treatment of acute exacerbations of schizophrenia

The objective of this study was to evaluate the efficacy and safety of divalproex sodium extended release (divalproex ER) vs placebo in combination with olanzapine or risperidone for the treatment of acute exacerbations of schizophrenia. In this 12-week, randomized, double-blind, parallel-group, multi-center trial, a total of 402 patients were randomized and treated; 103 received olanzapine/placebo, 99 received olanzapine/divalproex ER, 101 received risperidone/placebo, and 99 received risperidone/divalproex ER. Divalproex ER was initiated on day 1 at 20 mg/kg per day q AM and was titrated to clinical effect on days 3, 7, and 10, not to exceed a maximum dosage of 35 mg/kg per day. Olanzapine and risperidone were initiated at 5 and 2 mg/day q PM, respectively, increased to 10 and 4 mg/day on day 3, and increased to fixed target doses of 15 and 6 mg/day on day 6. No significant treatment difference was demonstrated between the combination therapy and antipsychotic monotherapy groups on the primary efficacy variable of the mean change from baseline to day 14 last observation carried forward on the Positive and Negative Syndrome Scale (PANSS) total score, although antipsychotic monotherapy did demonstrate superiority to combination therapy on the PANSS Negative subscale at several time points. Combination therapy also failed to show an advantage over antipsychotic monotherapy at day 84 on the PANSS total score. Most adverse events observed in the study were mild to moderate in severity, and the overall number of adverse events did not differ significantly between the combination therapy groups and their corresponding antipsychotic monotherapy group.

Schizophrenia: moving beyond monoamine antagonists

Schizophrenia is a disabling psychiatric disorder characterized by positive, negative, and cognitive symptoms. The first pharmacological treatments for schizophrenia were discovered by serendipitous, albeit carefully documented, clinical observations. The discovery of chlorpromazine and other dopamine D2 receptor antagonists as antipsychotic agents set the early course of drug discovery in the context of schizophrenia and other psychiatric disorders, and various monoamine receptors became the prime focus of neuropharmacological studies. Success in treating the positive symptoms nevertheless remained limited by the general lack of efficacy in addressing negative symptoms and cognitive impairment. In recent years, several new experimental approaches have emerged for the identification and treatment of different symptom clusters that do not rely on blockade of monoamine receptors. Muscarinic, nicotinic, and glutamatergic signaling mechanisms have become essential to neuropharmacological and behavioral models of discrete aspects of schizophrenia. And as a consequence of these insights, novel drug entities have become available to study and potentially treat the disabling cognitive and negative symptoms of psychiatric disease. Current attempts to target a new range of receptors entail unprecedented fine-tuning in the pharmacological manipulation of specific receptor subtypes.