scholarly journals N-methyl-D-aspartate receptor availability in first-episode psychosis: a PET-MR brain imaging study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Katherine Beck ◽  
Atheeshaan Arumuham ◽  
Mattia Veronese ◽  
Barbara Santangelo ◽  
Colm J. McGinnity ◽  
...  
Keyword(s):  
Temporal Cortex ◽  
Imaging Study ◽  
Volume Ratio ◽  
Brain Regions ◽  
First Episode Psychosis ◽  
Anterior Cingulate ◽  
First Episode ◽  
Aspartate Receptor ◽  
Selective Ligand ◽  
Episode Psychosis

AbstractN-methyl-D-aspartate receptor (NMDAR) hypofunction is hypothesised to underlie psychosis but this has not been tested early in illness. To address this, we studied 40 volunteers (21 patients with first-episode psychosis and 19 matched healthy controls) using PET imaging with an NMDAR selective ligand, [18F]GE-179, that binds to the ketamine binding site to index its distribution volume ratio (DVR) and volume of distribution (VT). Hippocampal DVR, but not VT, was significantly lower in patients relative to controls (p = 0.02, Cohen’s d = 0.81; p = 0.15, Cohen’s d = 0.49), and negatively associated with total (rho = −0.47, p = 0.04), depressive (rho = −0.67, p = 0.002), and general symptom severity (rho = −0.74, p < 0.001). Exploratory analyses found no significant differences in other brain regions (anterior cingulate cortex, thalamus, striatum and temporal cortex). These findings are consistent with the NMDAR hypofunction hypothesis and identify the hippocampus as a key locus for relative NMDAR hypofunction, although further studies should test specificity and causality.

scholarly journals N-Methyl-D-Aspartate Receptor binding in First-Episode Psychosis: A PET brain imaging study

BJPsych Open ◽  
2021 ◽  
Vol 7 (S1) ◽  
pp. S7-S7
Author(s):  
Katherine Beck ◽  
Atheeshaan Arumuham ◽  
Barbara Santangelo ◽  
Mattia Veronese ◽  
Robert McCutcheon ◽  
...  
Keyword(s):  
Symptom Severity ◽  
First Episode Psychosis ◽  
Anterior Cingulate ◽  
First Episode ◽  
Healthy Controls ◽  
Cohen’S D ◽  
Aspartate Receptor ◽  
Selective Ligand ◽  
Episode Psychosis ◽  
Cohen's D

AimsEvidence from genetics, post mortem and animal studies suggest that N-Methyl-D-Aspartate Receptor (NMDAR) hypofunction has an important role in the pathophysiology of psychosis. However, it is not known if NMDAR activity is altered in the early stages of psychosis or if this links to symptom severity. Our aim was to investigate NMDAR availability in first-episode psychosis (FEP) and determine if it links to symptom severity. The NMDAR hypofunction hypothesis of schizophrenia was initially proposed in the 1990s on the basis of observations that ketamine and phencyclidine (PCP) induced the full range of schizophrenia-like symptoms (positive, negative and cognitive) when given to healthy participants and also that they worsen symptoms in patients with schizophrenia.MethodWe recruited 40 volunteers, including 21 patients with schizophrenia from early intervention services in London (12 antipsychotic-free and 9 receiving antipsychotic medication) and 19 matched healthy controls. The uptake of an NMDAR selective ligand, [18F]GE179, was measured using positron emission tomography (PET) and indexed using the distribution volume ratio (DVR) and volume of distribution (VT, in millilitres per cubic centimetre) of [18F]GE179 in the hippocampus and additional exploratory regions (anterior cingulate cortex (ACC), thalamus, striatum and temporal lobe). Symptom severity was measured using the Positive and Negative Syndrome Scale (PANSS).ResultA total of 37 individuals were included in the analyses (mean [SD] age of controls, 26.7 [4.5] years; mean [SD] age of patients, 25.3 [4.9] years). There was a significant reduction in hippocampal DVR in the patients with schizophrenia relative to healthy controls (p = 0.02, Cohen's d = 0.81). Although the VT of [18F]GE179 was lower in absolute terms in patients, there was no significant effect of group on VT in the hippocampus (p = 0.15, Cohen's d = 0.49) or the exploratory brain regions. There was a negative association between hippocampal DVR and total PANSS symptoms (rho = –0.47, p = 0.04), depressive symptoms (rho = –0.67, p = 0.002), and general PANSS symptoms (rho = –0.74, p = 0.001).ConclusionThese results indicate lower hippocampal NMDAR levels in schizophrenia relative to controls with a large effect size, and that lower NMDAR levels are associated with greater levels of symptom severity. These findings are consistent with the role of NMDAR hypofunction in the pathophysiology of schizophrenia; however, further work is required to test specificity and causal relationships.

scholarly journals Longitudinal changes in brain metabolites in healthy subjects and patients with first episode psychosis (FEP): a 7-Tesla MRS study

2020 ◽  
Author(s):  
Min Wang ◽  
Peter B. Barker ◽  
Nicola Cascella ◽  
Jennifer M. Coughlin ◽  
Gerald Nestadt ◽  
...  
Keyword(s):  
Young Adulthood ◽  
Brain Regions ◽  
First Episode Psychosis ◽  
Anterior Cingulate ◽  
7 Tesla ◽  
First Episode ◽  
Resonance Spectroscopy ◽  
Invasive Approach ◽  
Longitudinal Changes ◽  
Episode Psychosis

AbstractObjective7 Tesla (T) longitudinal magnetic resonance spectroscopy (MRS) offers a precise measurment of metabolic levels in human brain via a non-invasive approach. Studying longitudinal changes in neurometabolites could help identify trait and state markers for diseases and understand inconsistent findings from different researchers due to differences in the age of study participants and duration of illness. This study is the first to report novel longitudinal patterns in young adulthood from both physiological and pathological viewpoints using 7T MRS.MethodsUtilizing a four-year longitudinal cohort with 38 first episode psychosis (FEP) patients (onset within 2 years) and 48 healthy controls (HC), the authors examined the annual percentage changes of 9 neurometabolites in 5 brain regions.ResultsBoth FEP patients and HC subjects were found to have significant longitudinal reductions in glutamate (Glu) in the anterior cingulate cortex (ACC). Only FEP patients were found to have a significant decrease over time in γ-aminobutyric acid (GABA), N-acetyl aspartate (NAA), myo-inositol (mI), and total choline (tCho: phosphocholine plus glycerophosphocholine) in the ACC. Uniquely, glutathione (GSH) was found to have a near zero annual percentage change in both FEP patients and HC subjects in all 5 brain regions over a four-year timespan in young adulthood.ConclusionsGSH could be a trait marker for diagnostic applications at least in young adulthood. Glu, GABA, NAA, mI, and tCho in the ACC are associated with the patient’s status and could be state markers for mechanistic studies of psychotic disorders, including those for progressive pathological changes and medication effects in young adulthood.

Lack of progression of brain abnormalities in first-episode psychosis: a longitudinal magnetic resonance imaging study

2010 ◽  
Vol 41 (8) ◽  
pp. 1677-1689 ◽  
Author(s):  
M. S. Schaufelberger ◽  
J. M. Lappin ◽  
F. L. S. Duran ◽  
P. G. P. Rosa ◽  
R. R. Uchida ◽  
...  
Keyword(s):  
Grey Matter ◽  
Temporal Cortex ◽  
Imaging Study ◽  
Population Based ◽  
First Episode Psychosis ◽  
First Episode ◽  
Grey Matter Volume ◽  
Matter Volume ◽  
Episode Psychosis ◽  
Brain Changes

BackgroundSome neuroimaging studies have supported the hypothesis of progressive brain changes after a first episode of psychosis. We aimed to determine whether (i) first-episode psychosis patients would exhibit more pronounced brain volumetric changes than controls over time and (ii) illness course/treatment would relate to those changes.MethodLongitudinal regional grey matter volume and ventricle:brain ratio differences between 39 patients with first-episode psychosis (including schizophrenia and schizophreniform disorder) and 52 non-psychotic controls enrolled in a population-based case-control study.ResultsWhile there was no longitudinal difference in ventricle:brain ratios between first-episode psychosis subjects and controls, patients exhibited grey matter volume changes, indicating a reversible course in the superior temporal cortex and hippocampus compared with controls. A remitting course was related to reversal of baseline temporal grey matter deficits.ConclusionsOur findings do not support the hypothesis of brain changes indicating a progressive course in the initial phase of psychosis. Rather, some brain volume abnormalities may be reversible, possibly associated with a better illness course.

Conceptual disorganization and redistribution of resting state cortical hubs in untreated first episode psychosis: A 7T MRI study

2020 ◽  
Author(s):  
Avyarthana Dey ◽  
Kara Dempster ◽  
Michael Mackinley ◽  
Peter Jeon ◽  
Tushar Das ◽  
...  
Keyword(s):  
Negative Symptoms ◽  
Superior Temporal Gyrus ◽  
Brain Regions ◽  
First Episode Psychosis ◽  
Cortical Reorganization ◽  
First Episode ◽  
Formal Thought Disorder ◽  
Whole Brain ◽  
Episode Psychosis ◽  
Positive And Negative Symptoms

Background:Network level dysconnectivity has been studied in positive and negative symptoms of schizophrenia. Conceptual disorganization (CD) is a symptom subtype which predicts impaired real-world functioning in psychosis. Systematic reviews have reported aberrant connectivity in formal thought disorder, a construct related to CD. However, no studies have investigated whole-brain functional correlates of CD in psychosis. We sought to investigate brain regions explaining the severity of CD in patients with first-episode psychosis (FEPs) compared with healthy controls (HCs).Methods:We computed whole-brain binarized degree centrality maps of 31 FEPs, 25 HCs and characterized the patterns of network connectivity in the two groups. In FEPs, we related these findings to the severity of CD. We also studied the effect of positive and negative symptoms on altered network connectivity.Results:Compared to HCs, reduced hubness of a right superior temporal gyrus (rSTG) cluster was observed in the FEPs. In patients exhibiting high CD, increased hubness of a medial superior parietal (mSPL) cluster was observed, compared to patients exhibiting low CD. These two regions were strongly correlated with CD scores but not with other symptom scores.Discussion:Our observations are congruent with previous findings of reduced but not increased hubness. We observed increased hubness of mSPL suggesting that cortical reorganization occurs to provide alternate routes for information transfer.Conclusion:These findings provide insight into the underlying neural processes mediating the presentation of symptoms in untreated FEP. A longitudinal tracking of the symptom course will be useful to assess the mechanisms underlying these compensatory changes.

scholarly journals Treatment response after 6 and 26 weeks is related to baseline glutamate and GABA levels in antipsychotic-naïve patients with psychosis

2019 ◽  
Vol 50 (13) ◽  
pp. 2182-2193 ◽  
Author(s):  
Kirsten B. Bojesen ◽  
Bjørn H. Ebdrup ◽  
Kasper Jessen ◽  
Anne Sigvard ◽  
Karen Tangmose ◽  
...  
Keyword(s):  
Psychotic Disorders ◽  
Poor Response ◽  
First Episode Psychosis ◽  
Anterior Cingulate ◽  
First Episode ◽  
Antipsychotic Treatment ◽  
Resonance Spectroscopy ◽  
Reference Levels ◽  
Clinical Prognosis ◽  
Episode Psychosis

AbstractBackgroundPoor response to dopaminergic antipsychotics constitutes a major challenge in the treatment of psychotic disorders and markers for non-response during first-episode are warranted. Previous studies have found increased levels of glutamate and γ-aminobutyric acid (GABA) in non-responding first-episode patients compared to responders, but it is unknown if non-responders can be identified using reference levels from healthy controls (HCs).MethodsThirty-nine antipsychotic-naïve patients with first-episode psychosis and 36 matched HCs underwent repeated assessments with the Positive and Negative Syndrome Scale and 3T magnetic resonance spectroscopy. Glutamate scaled to total creatine (/Cr) was measured in the anterior cingulate cortex (ACC) and left thalamus, and levels of GABA/Cr were measured in ACC. After 6 weeks, we re-examined 32 patients on aripiprazole monotherapy and 35 HCs, and after 26 weeks we re-examined 30 patients on naturalistic antipsychotic treatment and 32 HCs. The Andreasen criteria defined non-response.ResultsBefore treatment, thalamic glutamate/Cr was higher in the whole group of patients but levels normalized after treatment. ACC levels of glutamate/Cr and GABA/Cr were lower at all assessments and unaffected by treatment. When compared with HCs, non-responders at week 6 (19 patients) and week 26 (16 patients) had higher baseline glutamate/Cr in the thalamus. Moreover, non-responders at 26 weeks had lower baseline GABA/Cr in ACC. Baseline levels in responders and HCs did not differ.ConclusionGlutamatergic and GABAergic abnormalities in antipsychotic-naïve patients appear driven by non-responders to antipsychotic treatment. If replicated, normative reference levels for glutamate and GABA may aid estimation of clinical prognosis in first-episode psychosis patients.

scholarly journals Cortical thickness and surface area correlates with cognitive dysfunction among first-episode psychosis patients

2016 ◽  
Vol 46 (10) ◽  
pp. 2145-2155 ◽  
Author(s):  
L. Haring ◽  
A. Müürsepp ◽  
R. Mõttus ◽  
P. Ilves ◽  
K. Koch ◽  
...  
Keyword(s):  
Structure Function ◽  
Surface Area ◽  
Cortical Thickness ◽  
Brain Structure ◽  
Brain Mri ◽  
Brain Regions ◽  
First Episode Psychosis ◽  
First Episode ◽  
Neurocognitive Performance ◽  
Episode Psychosis

BackgroundIn studies using magnetic resonance imaging (MRI), some have reported specific brain structure–function relationships among first-episode psychosis (FEP) patients, but findings are inconsistent. We aimed to localize the brain regions where cortical thickness (CTh) and surface area (cortical area; CA) relate to neurocognition, by performing an MRI on participants and measuring their neurocognitive performance using the Cambridge Neuropsychological Test Automated Battery (CANTAB), in order to investigate any significant differences between FEP patients and control subjects (CS).MethodExploration of potential correlations between specific cognitive functions and brain structure was performed using CANTAB computer-based neurocognitive testing and a vertex-by-vertex whole-brain MRI analysis of 63 FEP patients and 30 CS.ResultsSignificant correlations were found between cortical parameters in the frontal, temporal, cingular and occipital brain regions and performance in set-shifting, working memory manipulation, strategy usage and sustained attention tests. These correlations were significantly dissimilar between FEP patients and CS.ConclusionsSignificant correlations between CTh and CA with neurocognitive performance were localized in brain areas known to be involved in cognition. The results also suggested a disrupted structure–function relationship in FEP patients compared with CS.

scholarly journals Brain structural correlates of functional capacity in first-episode psychosis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Erkan Alkan ◽  
Geoff Davies ◽  
Kathy Greenwood ◽  
Simon L. Evans
Keyword(s):  
Functional Capacity ◽  
Gray Matter Volume ◽  
Brain Regions ◽  
First Episode Psychosis ◽  
First Episode ◽  
Control Group ◽  
Neural Basis ◽  
Antipsychotic Therapy ◽  
Brain Volumes ◽  
Episode Psychosis

Abstract Impaired functional capacity is a core feature of schizophrenia and presents even in first-episode psychosis (FEP) patients. Impairments in daily functioning tend to persist despite antipsychotic therapy but their neural basis is less clear. Previous studies suggest that volume loss in frontal cortex might be an important contributor, but findings are inconsistent. We aimed to comprehensively investigate the brain structural correlates of functional capacity in FEP using MRI and a reliable objective measure of functioning [University of California, San Diego Performance-Based Skills Assessment (UPSA)]. In a sample of FEP (n = 39) and a well-matched control group (n = 21), we measured cortical thickness, gray matter volume, and white matter tract integrity (fractional anisotropy, FA) within brain regions implicated by previous work. The FEP group had thinner cortex in various frontal regions and fusiform, and reduced FA in inferior longitudinal fasciculus (ILF). In FEP, poorer functional capacity correlated with reduced superior frontal volume and lower FA in left ILF. Importantly, frontal brain volumes and integrity of the ILF were identified as the structural correlates of functional capacity in FEP, controlling for other relevant factors. These findings enhance mechanistic understanding of functional capacity deficits in schizophrenia by specifying the underlying neural correlates. In future, this could help inform intervention strategies.

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