Dataset Information

Association of Hippocampal Glutamate Levels With Adverse Outcomes in Individuals at Clinical High Risk for Psychosis.

ABSTRACT:

Importance

Preclinical and human data suggest that hippocampal dysfunction plays a critical role in the onset of psychosis. Neural hyperactivity in the hippocampus is thought to drive an increase in subcortical dopamine function through glutamatergic projections to the striatum.

Objective

To examine the association between hippocampal glutamate levels in individuals at clinical high risk for psychosis and their subsequent clinical outcomes.

Design, setting, and participants

This cross-sectional study of 86 individuals at clinical high risk for psychosis and 30 healthy control individuals, with a mean follow-up of 18.5 months, was conducted between November 1, 2011, and November 1, 2017, at early detection services in London and Cambridge, United Kingdom.

Main outcomes and measures

Concentrations of glutamate and other metabolites were measured in the left hippocampus using 3-T proton magnetic resonance spectroscopy at the first clinical presentation. At follow-up, clinical outcomes were assessed in terms of transition or nontransition to psychosis using the Comprehensive Assessment of the At-Risk Mental State criteria and the level of overall functioning using the Global Assessment of Function scale.

Results

Of 116 total participants, 86 were at clinical high risk for psychosis (50 [58%] male; mean [SD] age, 22.4 [3.5] years) and 30 were healthy controls (14 [47%] male; mean [SD] age, 24.7 [3.8] years). At follow-up, 12 clinical high-risk individuals developed a first episode of psychosis whereas 74 clinical high-risk individuals did not; 19 clinical high-risk individuals showed good overall functioning (Global Assessment of Function ≥65), whereas 38 clinical high-risk individuals had a poor functional outcome (Global Assessment of Function <65). Compared with clinical high-risk individuals who did not become psychotic, clinical high-risk individuals who developed psychosis showed higher hippocampal glutamate levels (mean [SD], 8.33 [1.48] vs 9.16 [1.28] glutamate levels; P = .048). The clinical high-risk individuals who developed psychosis also had higher myo-inositol levels (mean [SD], 7.60 [1.23] vs 6.24 [1.36] myo-inositol levels; P = .002) and higher creatine levels (mean [SD], 8.18 [0.74] vs 7.32 [1.09] creatine levels; P = .01) compared with clinical high-risk individuals who did not become psychotic, and higher myo-inositol levels compared with healthy controls (mean [SD], 7.60 [1.23] vs 6.19 [1.51] myo-inositol levels; P = .005). Higher hippocampal glutamate levels in clinical high-risk individuals were also associated with a poor functional outcome (mean [SD], 8.83 [1.43] vs 7.76 [1.40] glutamate levels; P = .02). In the logistic regression analyses, hippocampal glutamate levels were significantly associated with clinical outcome in terms of transition and nontransition to psychosis (β = 0.48; odds ratio = 1.61; 95% CI, 1.00-2.59; P = .05) and overall functioning (β = 0.53; odds ratio = 1.71; 95% CI, 1.10-2.66; P = .02).

Conclusions and relevance

The findings indicate that adverse clinical outcomes in individuals at clinical high risk for psychosis may be associated with an increase in baseline hippocampal glutamate levels, as well as an increase in myo-inositol and creatine levels. This conclusion suggests that these measures could contribute to the stratification of clinical high-risk individuals according to future clinical outcomes.

SUBMITTER: Bossong MG

PROVIDER: S-EPMC6440239 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:ImportanceThe development of adverse clinical outcomes in patients with psychosis has been associated with behavioral and neuroanatomical deficits related to emotion processing. However, the association between alterations in brain regions subserving emotion processing and clinical outcomes remains unclear.ObjectiveTo examine the association between alterations in emotion processing and regional gray matter volumes in individuals at clinical high risk (CHR) for psychosis, and the association with subsequent clinical outcomes.Design, setting, and participantsThis naturalistic case-control study with clinical follow-up at 12 months was conducted from July 1, 2010, to August 31, 2016, and collected data from 9 psychosis early detection centers (Amsterdam, Basel, Cologne, Copenhagen, London, Melbourne, Paris, The Hague, and Vienna). Participants (213 individuals at CHR and 52 healthy controls) were enrolled in the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) project. Data were analyzed from October 1, 2018, to April 24, 2019.Main measures and outcomesEmotion recognition was assessed with the Degraded Facial Affect Recognition Task. Three-Tesla magnetic resonance imaging scans were acquired from all participants, and gray matter volume was measured in regions of interest (medial prefrontal cortex, amygdala, hippocampus, and insula). Clinical outcomes at 12 months were evaluated for transition to psychosis using the Comprehensive Assessment of At-Risk Mental States criteria, and the level of overall functioning was measured through the Global Assessment of Functioning [GAF] scale.ResultsA total of 213 individuals at CHR (105 women [49.3%]; mean [SD] age, 22.9 [4.7] years) and 52 healthy controls (25 women [48.1%]; mean [SD] age, 23.3 [4.0] years) were included in the study at baseline. At the follow-up within 2 years of baseline, 44 individuals at CHR (20.7%) had developed psychosis and 169 (79.3%) had not. Of the individuals at CHR reinterviewed with the GAF, 39 (30.0%) showed good overall functioning (GAF score, ?65), whereas 91 (70.0%) had poor overall functioning (GAF score, <65). Within the CHR sample, better anger recognition at baseline was associated with worse functional outcome (odds ratio [OR],?0.88; 95% CI,?0.78-0.99; P?=?.03). In individuals at CHR with a good functional outcome, positive associations were found between anger recognition and hippocampal volume (ze?=?3.91; familywise error [FWE] P?=?.02) and between fear recognition and medial prefrontal cortex volume (z?=?3.60; FWE P?=?.02), compared with participants with a poor outcome. The onset of psychosis was not associated with baseline emotion recognition performance (neutral OR, 0.93; 95% CI, 0.79-1.09; P?=?.37; happy OR, 1.03; 95% CI, 0.84-1.25; P?=?.81; fear OR, 0.98; 95% CI, 0.85-1.13; P?=?.77; anger OR, 1.00; 95% CI, 0.89-1.12; P?=?.96). No difference was observed in the association between performance and regional gray matter volumes in individuals at CHR who developed or did not develop psychosis (FWE P?<?.05).Conclusions and relevanceIn this study, poor functional outcome in individuals at CHR was found to be associated with baseline abnormalities in recognizing negative emotion. This finding has potential implications for the stratification of individuals at CHR and suggests that interventions that target socioemotional processing may improve functional outcomes.