Reward disturbances in antipsychotic-naïve patients with first-episode psychosis and their association to glutamate levels

2021 ◽  
pp. 1-10
Author(s):  
Karen Tangmose ◽  
Egill Rostrup ◽  
Kirsten B Bojesen ◽  
Anne Sigvard ◽  
Kasper Jessen ◽  
...  

Abstract Background Aberrant anticipation of motivational salient events and processing of outcome evaluation in striatal and prefrontal regions have been suggested to underlie psychosis. Altered glutamate levels have likewise been linked to schizophrenia. Glutamatergic abnormalities may affect the processing of motivational salience and outcome evaluation. It remains unresolved, whether glutamatergic dysfunction is associated with the coding of motivational salience and outcome evaluation in antipsychotic-naïve patients with first-episode psychosis. Methods Fifty-one antipsychotic-naïve patients with first-episode psychosis (22 ± 5.2 years, female/male: 31/20) and 52 healthy controls (HC) matched on age, sex, and parental education underwent functional magnetic resonance imaging and magnetic resonance spectroscopy (3T) in one session. Brain responses to motivational salience and negative outcome evaluation (NOE) were examined using a monetary incentive delay task. Glutamate levels were estimated in the left thalamus and anterior cingulate cortex using LCModel. Results Patients displayed a positive signal change to NOE in the caudate (p = 0.001) and dorsolateral prefrontal cortex (DLPFC; p = 0.003) compared to HC. No group difference was observed in motivational salience or in levels of glutamate. There was a different association between NOE signal in the caudate and DLPFC and thalamic glutamate levels in patients and HC due to a negative correlation in patients (caudate: p = 0.004, DLPFC: p = 0.005) that was not seen in HC. Conclusions Our findings confirm prior findings of abnormal outcome evaluation as a part of the pathophysiology of schizophrenia. The results also suggest a possible link between thalamic glutamate and NOE signaling in patients with first-episode psychosis.

2020 ◽  
Author(s):  
Pan Yunzhi ◽  
Kara Dempster ◽  
Peter Jeon ◽  
Jean Théberge ◽  
Ali Khan ◽  
...  

Background: Disorganized thinking is a core feature of acute psychotic episodes that is linked to social and vocational functioning. Based on the close association between cingulum and disorganized thinking, we examine three candidate mechanistic markers in relation to acute conceptual disorganization (CD) in first episode psychosis: glutamate excess; cortical antioxidant (glutathione) status and the integrity of the cingulum bundle. Methods: We used fractional anisotropy (FA) maps from 7T diffusion-weighted imaging to investigate bilateral cingulum based on a probabilistic white-matter atlas. We compared the high-CD, low-CD and healthy control groups and performed probabilistic fiber tracking from the identified clusters (ROI within cingulum) to the rest of the brain. We quantified glutamate and glutathione with magnetic-resonance-spectroscopy (MRS) in the dorsal anterior cingulate cortex.Results: There was a significant FA reduction (F=9.04; p=0.036) in a cluster in left cingulum in high-CD compared to low-CD (Cohen’s d=1.39; p=0.003) and controls (Cohen’s d=0.86; p=0.009). Glutamate levels did not vary among the groups, but glutathione levels were higher in high-CD compared to the low-CD group. Higher glutathione related to lower FA in the high-CD group in the cingulum cluster.Discussion: Acute CD relates to indicators of oxidative stress as well as reduced white matter integrity of the cingulum but not to MRI-based glutamatergic excess. We propose that both oxidative imbalance and structural dysconnectivity underlie acute disorganization.Limitation: MRS measures of glutamine were highly uncertain and MRs was acquired from a single voxel only.


2019 ◽  
Vol 50 (13) ◽  
pp. 2182-2193 ◽  
Author(s):  
Kirsten B. Bojesen ◽  
Bjørn H. Ebdrup ◽  
Kasper Jessen ◽  
Anne Sigvard ◽  
Karen Tangmose ◽  
...  

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.


2020 ◽  
Author(s):  
Min Wang ◽  
Peter B. Barker ◽  
Nicola Cascella ◽  
Jennifer M. Coughlin ◽  
Gerald Nestadt ◽  
...  

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.


2017 ◽  
Vol 26 (2) ◽  
pp. 122-128 ◽  
Author(s):  
L. Squarcina ◽  
J. A. Stanley ◽  
M. Bellani ◽  
C. A. Altamura ◽  
P. Brambilla

Relevant biochemicals of the brain can be quantified in vivo, non-invasively, using proton Magnetic Resonance Spectroscopy (¹H MRS). This includes metabolites associated with neural general functioning, energetics, membrane phospholipid metabolism and neurotransmission. Moreover, there is substantial evidence of implication of the frontal and prefrontal areas in the pathogenesis of psychotic disorders such as schizophrenia. In particular, the anterior cingulate cortex (ACC) plays an important role in cognitive control of emotional and non-emotional processes. Thus the study of its extent of biochemistry dysfunction in the early stages of psychosis is of particular interest in gaining a greater understanding of its aetiology. In this review, we selected ¹H MRS studies focused on the ACC of first-episode psychosis (FEP). Four studies reported increased glutamatergic levels in FEP, while other four showed preserved concentrations. Moreover, findings on FEP do not fully mirror those in chronic patients. Due to conflicting findings, larger longitudinal ¹H MRS studies are expected to further explore glutamatergic neurotransmission in ACC of FEP in order to have a better understanding of the glutamatergic mechanisms underlying psychosis, possibly using ultra high field MR scanners.


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