The Current State of the Clinical High Risk for Psychosis Research Paradigm

Multimodal evidence of mediodorsal thalamus-prefrontal circuit dysfunctions in clinical high-risk for psychosis: findings from a combined 7T fMRI, MRSI and sleep Hd-EEG study

Deficits in mediodorsal thalamus-dorsolateral prefrontal cortex (MDT-DLPFC) resting-state functional magnetic resonance imaging (rs-fMRI) connectivity and prefrontal sleep spindles have been reported in chronic and early course schizophrenia. However, the presence of these alterations in clinical high-risk for psychosis (CHR), alongside their relationships with underlying neurotransmission and cognitive function, remains to be established. Thirty-one CHR and thirty-two HC underwent: 1) 7 T rs-fMRI; 2) 7 T magnetic resonance spectroscopy imaging (MRSI); and 3) sleep electroencephalography (EEG). Rs-fMRI connectivity was analyzed by seeding the whole thalamus (WT) and seven thalamic subsections. Spindle duration was computed across all EEG channels. GABA/creatine (Cr) and glutamate/Cr were calculated in DLPFC and MDT. Relative to HC, CHR showed WT-DLPFC hypoconnectivity (p-FDR = 0.001), especially involving MDT-DLPFC (p-FDR < 0.001) and reduced prefrontal spindle duration (t-stat = -2.64, p = 0.010), while no differences were found for MRSI neuro-metabolites. We then performed clustering analysis using rs-fMRI connectivity and spindle duration to identify CHR and HC subgroups and predict their working memory (WM) performance. A cluster with intact rs-fMRI and spindle duration included mostly HC (83.33% purity), while a cluster with both measures altered involved almost entirely CHR (91.66% purity) and showed worse WM performances. We also examined MRSI metabolites' contribution to spindles and rs-fMRI connectivity with a within-group multivariable regression analysis. In HC, but not in CHR, MDT glutamate/Cr negatively predicted spindle duration and positively predicted MDT-DLPFC connectivity. Combined, these findings indicate that a multimodal neuroimaging approach can identify distinct thalamocortical dysfunctions in CHR individuals, thus informing future research aimed at developing personalized interventions in these individuals.

Identifying clinical and proteomic markers for early diagnosis and prognosis prediction of major psychiatric disorders

BACKGROUND

To clarify if blood proteins can predict disease progression among individuals at clinical high-risk of severe mental illness (CHR-SMI), we developed a statistical model incorporating clinical and blood protein markers to distinguish the transition group (who developed severe mental illness) (CHR-SMI-T) and from non-transition group (CHR-SMI-NT) at baseline.

METHODS

Ninety individuals (74 at CHR-SMI: 16 patients) were monitored for ≤4 years and were the focus of predictive models. Three predictive models (1 [100 clinical variables], 2 [158 peptides], and 3 [100 clinical variables +158 peptides]) were evaluated using area under the receiver operating characteristic (AUROC) values. Clinical and protein feature patterns were evaluated by linear mixed-effect analysis within the model at 12 and 24 months among patients who did (CHR-SMI-T) and did not transition (CHR-SMI-NT) and the entire group.

RESULT

Eighteen CHR-SMI individuals with major psychiatric disorders (first episode psychosis: 2; bipolar II disorder: 13; major depressive disorder; 3) developed disorders over an average of 17.7 months. The combined model showed the highest discriminatory performance (AUROC = 0.73). Cytosolic malate dehydrogenase and transgelin-2 levels were lower in the CHR-SMI-T than the CHR-SMI-NT group. Complement component C9, inter-alpha-trypsin inhibitor heavy chain H4, von Willebrand factor, and C-reactive protein were lower in the patient than the CHR-SMI-NT group. These differences were non-significant after FDR adjustment.

LIMITATIONS

Small sample, no control for medication use.

CONCLUSION

This exploratory study identified clinical and proteomic markers that might predict severe mental illness early onset, which could aid in early detection and intervention. Future studies with larger samples and controlled variables are needed to validate these findings.

Serum Levels of Tumor Necrosis Factor-α and Vascular Endothelial Growth Factor in the Subtypes of Clinical High Risk Individuals: A Prospective Cohort Study

Introduction

Numerous studies have established the roles of inflammation and angioneurins in the pathogenesis of schizophrenia (SCZ). This study aimed to compare the serum levels of tumour necrosis factor (TNF)-α and vascular endothelial growth factor (VEGF) in patients at clinical high risk (CHR) for psychosis or SCZ at baseline and one year after treatment.

Methods

A total of 289 CHR participants from the Shanghai At Risk for Psychosis Extended Program (SHARP) were tracked for a year. They were divided into two and four subtypes based on symptom severity according to the Structured Interview for Prodromal Syndromes (SIPS) and received standard medical care. At baseline and one-year follow-up, TNF-α and VEGF were detected using enzyme-linked immunosorbent assay, and pathological features were assessed using the Global Assessment of Function (GAF) score.

Results

Baseline TNF-α levels did not differ significantly, while VEGF levels were lower in patients with more severe symptoms. VEGF showed a negative correlation with negative features, both overall (r = -0.212, p = 0.010) and in the subgroup with higher positive scores (r = -0.370, p = 0.005). TNF-α was positively correlated with negative symptoms in the subgroup with higher negative scores (r = 0.352, p = 0.002). A three-way multivariate analysis of variance demonstrated that participants in Subtype 1 of positive or negative symptoms performed better than those in Subtype 2, with significant main effects and interactions of group and both cytokines.

Discussion

TNF-α and VEGF levels are higher and lower, respectively, in CHR patients with more severe clinical symptoms, particularly negative symptoms, which point to a worsening inflammatory and vascular status in the brain.

Visuospatial Learning Selectively Enhanced by Personalized Transcranial Magnetic Stimulation over Parieto-Hippocampal Network among Patients at Clinical High-Risk for Psychosis

BACKGROUND AND HYPOTHESIS

Cognitive deficits in visuospatial learning (VSL) are highly associated with an increased risk of developing psychosis among populations with clinical high risk (CHR) for psychosis. Early interventions targeting VSL enhancement are warranted in CHR but remain rudimentary. We investigated whether personalized transcranial magnetic stimulation (TMS) over the left parieto-hippocampal network could improve VSL performance in CHR patients and if it could reduce the risk of psychosis conversion within 1 year.

STUDY DESIGN

Sixty-five CHR patients were randomized to receive active or sham TMS treatments using an accelerated TMS protocol, consisting of 10 sessions of 20 Hz TMS treatments within 2 days. TMS target was defined by individual parieto-hippocampal functional connectivity and precisely localized by individual structural magnetic resonance imaging. VSL performance was measured using Brief Visuospatial Memory Test-Revised included in measurement and treatment research to improve cognition in schizophrenia consensus cognitive battery (MCCB). Fifty-eight CHR patients completed the TMS treatments and MCCB assessments and were included in the data analysis.

STUDY RESULTS

We observed significant VSL improvements in the active TMS subgroup (Cohen's d = 0.71, P < .001) but not in the sham TMS subgroup (Cohen's d = 0.07, P = .70). In addition, active TMS improved the precision of VSL performance. At a 1-year follow-up, CHR patients who received active TMS showed a lower psychosis conversion rate than those who received sham TMS (6.7% vs 28.0%, χ2 = 4.45, P = .03).

CONCLUSIONS

Our findings demonstrate that personalized TMS in the left parieto-hippocampal network may be a promising preventive intervention that improves VSL in CHR patients and reduces the risk of psychosis conversion at follow-up.

Ethnoracial discrimination and the development of suspiciousness symptoms in individuals at clinical high-risk for psychosis

BACKGROUND AND HYPOTHESIS

While individuals at clinical high-risk (CHR) for psychosis experience higher levels of discrimination than healthy controls, it is unclear how these experiences contribute to the etiology of attenuated positive symptoms. The present study examined the association of perceived discrimination with positive symptoms in a cohort from the North American Prodrome Longitudinal Study (NAPLS2). It predicted that CHR individuals will report higher levels of lifetime and past year perceived discrimination related to their race and ethnicity (ethnoracial discrimination) and that this form of discrimination will be significantly associated with baseline positive symptoms.

STUDY DESIGN

Participants included 686 CHR and 252 healthy controls. The present study examined data from the perceived discrimination (PD) scale, the Brief Core Schema Scale, and the Scale for the Psychosis-Risk Symptoms. Structural equation modeling was employed to examine whether negative schema of self and others mediated the relation of past year ethnoracial PD to baseline suspiciousness symptoms.

RESULTS

CHR individuals report higher levels of past year and lifetime PD compared to healthy controls. Lifetime ethnoracial PD was associated with suspiciousness and total positive symptoms. Negative schema of self and others scores partially mediated the relation of past year ethnoracial PD to suspiciousness, one of five positive symptom criteria for CHR.

CONCLUSIONS

For CHR individuals, past year ethnoracial discrimination was associated with negative beliefs about themselves and others, which was associated with suspiciousness. These findings contribute to an emerging literature characterizing the mechanisms by which discrimination contributes to the positive symptoms characterizing the CHR syndrome.

Impact of ZNF804A rs1344706 or CACNA1C rs1006737 polymorphisms on cognition in patients with severe mental disorders: A systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis focussed on insights into the relationship between CACNA1C-rs1006737 and ZNF804A-rs1344706 polymorphisms and cognitive performance in schizophrenia (SCZ) spectrum and bipolar disorder (BD) and provide some contributions for clinical practice.

METHODS

We searched the websites databases (PubMED, PsycINFO, Web of Science, EMBASE and Cochrane Library) using eligibility and exclusion criteria to capture all potential studies, based on PICO model and according to the PRISMA.

RESULTS

Eight articles were included in this systematic review (five referring to CACNA1C-rs1006737 and three related to ZNF804A-rs1344706 polymorphisms), with a total of 5759 participants (1751 SCZ patients, 348 BD patients, 3626 controls and 34 first-degree relatives). The results demonstrated that the pooled effect of CACNA1C-rs1006737 (risk difference RD = 0.08; 95% CI 0.02-0.15) was associated with altered cognitive function in patients with severe mental disorders, but not ZNF804A-rs1344706 polymorphism (RD = 0.19; 95% CI 0.09-0.48.

CONCLUSION

The present meta-analysis provides evidence regarding slight association between CACNA1C-rs1006737 polymorphisms and cognitive performance in severe mental disorders, indicating that cognitive impairment in severe mental disorders associated with the CACNA1C rs1006737 risk variants could only be expressed when interacting with environmental exposures. This study is registered with PROSPERO, number CRD42021246726.

Plasma metabolic alterations and potential biomarkers in individuals at clinical high risk for psychosis

BACKGROUND

Early identification and treatment of clinical high-risk for psychosis (CHRP) are critical to prevent the onset of psychosis, but there is no objective biomarker for CHR-P diagnosis.

METHODS

Ninety medication naïve CHR-P subjects and eighty-six healthy controls (HCs) were recruited. The metabolic profiles of plasma samples were acquired using an untargeted metabolomics approach based on ultra-high-performance liquid chromatography equipped with quadrupole time-of-flight mass spectrometry. The obtained data were further mapped on the Kyoto Encyclopedia of Genes and Genomes for pathway analysis, and an ensemble learning method was applied to identify diagnostic biomarkers. Bayesian linear regression model was then used to explore predicative biomarkers of conversion to psychosis. Receiver-operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic or predicative value of potential biomarkers.

RESULTS

A total of one hundred and four differential metabolites and forty-eight differential pathways were identified. A panel of five metabolites was found that could effectively discriminate CHR-P from HCs with area under the ROC curve of 1 in the training set (70% of the samples) and 0.997 in the testing set (30% of the samples). The biosynthesis of unsaturated fatty acids pathway perturbed most significantly in CHR-P subjects. Twenty-three CHR-P subjects converted to psychotic disorders during two-year follow-up, and increased 1-stearoyl-2-arachidonoyl-sn-glycerol in plasma was potentially associated with the higher risk of conversion to psychosis.

CONCLUSIONS

These findings demonstrate the alterations of plasma metabolic profiles in CHR-P population, which may deliver valuable biomarkers for early identification and outcome prediction of CHR-P.

Glutathione as a Molecular Marker of Functional Impairment in Patients with At-Risk Mental State: 7-Tesla 1H-MRS Study

A substantial number of individuals with clinical high-risk (CHR) mental state do not transition to psychosis. However, regardless of future diagnostic trajectories, many of these individuals develop poor social and occupational functional outcomes. The levels of glutathione, a crucial cortical antioxidant, may track variations in functional outcomes in early psychosis and prodromal states. Thirteen clinical high-risk and 30 healthy control volunteers were recruited for a 7-Tesla magnetic resonance spectroscopy scan with a voxel positioned within the dorsal anterior cingulate cortex (ACC). Clinical assessment scores were collected to determine if any association was observable with glutathione levels. The Bayesian Spearman's test revealed a positive association between the Social and Occupational Functioning Assessment Scale (SOFAS) and the glutathione concentration in the clinical high-risk group but not in the healthy control group. After accounting for variations in the SOFAS scores, the CHR group had higher GSH levels than the healthy subjects. This study is the first to use 7-Tesla magnetic resonance spectroscopy to test whether ACC glutathione levels relate to social and occupational functioning in a clinically high-risk group and offers preliminary support for glutathione levels as a clinically actionable marker of prognosis in emerging adults presenting with risk features for various severe mental illnesses.

The Interplay Between Postsynaptic Striatal D2/3 Receptor Availability, Adversity Exposure and Odd Beliefs: A [11C]-Raclopride PET Study

BACKGROUND

Between unaffected mental health and diagnosable psychiatric disorders, there is a vast continuum of functioning. The hypothesized link between striatal dopamine signaling and psychosis has guided a prolific body of research. However, it has been understudied in the context of multiple interacting factors, subclinical phenotypes, and pre-postsynaptic dynamics.

METHOD

This work investigated psychotic-like experiences and D2/3 dopamine postsynaptic receptor availability in the dorsal striatum, quantified by in vivo [11C]-raclopride positron emission tomography, in a sample of 24 healthy male individuals. Additional mediation and moderation effects with childhood trauma and key dopamine-regulating genes were examined.

RESULTS

An inverse relationship between nondisplaceable binding potential and subclinical symptoms was identified. D2/3 receptor availability in the left putamen fully mediated the association between traumatic childhood experiences and odd beliefs, that is, inclinations to see meaning in randomness and unfounded interpretations. Moreover, the effect of early adversity was moderated by a DRD2 functional variant (rs1076560). The results link environmental and neurobiological influences in the striatum to the origination of psychosis spectrum symptomology, consistent with the social defeat and diathesis-stress models.

CONCLUSIONS

Adversity exposure may affect the dopamine system as in association with biases in probabilistic reasoning, attributional style, and salience processing. The inverse relationship between D2/3 availability and symptomology may be explained by endogenous dopamine occupying the receptor, postsynaptic compensatory mechanisms, and/or altered receptor sensitivity. This may also reflect a cognitively stabilizing mechanism in non-help-seeking individuals. Future research should comprehensively characterize molecular parameters of dopamine neurotransmission along the psychosis spectrum and according to subtype profiling.