C-reactive protein and post-stroke depressive symptoms

Innate immunity-mediated neuroinflammation promotes the onset and progression of post-stroke depression

Post-stroke depression (PSD) is a prevalent psychiatric disorder after stroke, with the incidence of approximately one-third among stroke survivors. It is classified as an organic mental disorder and has a well-documented association with stroke affecting various aspects of patients, such as the recovery of limb motor function, daily living self-care ability, and increasing the mortality of stroke survivors. However, the pathogenesis of PSD is not yet fully understood. Currently, immune inflammation is a research hotspot. This review focuses on the pathogenesis of PSD, particularly elucidating the role of inflammation in mediating neuroinflammation through innate immunity. Simultaneously, we highlight that peripheral inflammation following a stroke may trigger a detrimental cycle of neuroinflammation by activating innate immune pathways within the central nervous system, which could potentially contribute to the development of PSD. Lastly, we summarize potential treatments for PSD and propose targeting cytokines and innate immune pathways as novel therapeutic approaches.

Validity of evaluation scales for post-stroke depression: a systematic review and meta-analysis

BACKGROUND

Post-stroke depression (PSD) is closely associated with poor stroke prognosis. However, there are some challenges in identifying and assessing PSD. This study aimed to identify scales for PSD diagnosis, assessment, and follow-up that are straightforward, accurate, efficient, and reproducible.

METHODS

A systematic literature search was conducted in 7 electronic databases from January 1985 to December 2023.

RESULTS

Thirty-two studies were included, the Patient Health Questionnaire-9 (PHQ-9) and Hamilton Depression Scale (HDRS) had higher diagnostic accuracy for PSD. The sensitivity, specificity, and diagnostic odds ratio of PHQ-9 or diagnosing any depression were 0.82, 0.87, and 29 respectively. And for HDRS, used for diagnosing major depression, the scores were 0.92, 0.89, and 94. Furthermore, these two scales also had higher diagnostic accuracy in assessing depressive symptoms during both the acute and chronic phases of stroke. In patients with post-stroke aphasia and cognitive impairment, highly diagnostic scales have not been identified for assessing depressive symptoms yet.

CONCLUSIONS

The PHQ-9 and HDRS scales are recommended to assess PSD. HDRS, which demonstrates high diagnostic performance, can replace structured interviews based on diagnostic criteria.

Dementia after Ischemic Stroke, from Molecular Biomarkers to Therapeutic Options

Ischemic stroke is a leading cause of disability worldwide. While much of post-stroke recovery is focused on physical rehabilitation, post-stroke dementia (PSD) is also a significant contributor to poor functional outcomes. Predictive tools to identify stroke survivors at risk for the development of PSD are limited to brief screening cognitive tests. Emerging biochemical, genetic, and neuroimaging biomarkers are being investigated in an effort to unveil better indicators of PSD. Additionally, acetylcholinesterase inhibitors, NMDA receptor antagonists, dopamine receptor agonists, antidepressants, and cognitive rehabilitation are current therapeutic options for PSD. Focusing on the chronic sequelae of stroke that impair neuroplasticity highlights the need for continued investigative trials to better assess functional outcomes in treatments targeted for PSD.

Post-Stroke Depression in Older Adults: An Overview

Detailed data on post-stroke depression (PSD) in older adults are limited in spite of the high vulnerability of this population to stroke. In fact, PSD prevalence in older adults ranges from 16.0 to 43.9%; however, timing and instruments of evaluation often differ significantly across all available studies. The etiology, genetic and inflammatory factors, as well as structural brain alterations, are claimed as part of a multifaceted mechanism of action in PSD onset. Thus, the aim of this narrative review was to further elaborate on the prevalence, etiology, diagnosis, consequences and treatment of PSD in older adults. The consequences of PSD in older adults may be devastating, including a poor functional outcome after rehabilitation and lower medication adherence. In addition, lower quality of life and reduced social participation, higher risk of new stroke, rehospitalization, and mortality have been reported. In this scenario, treating PSD represents a crucial step to prevent these complications. Both pharmacological and non-pharmacological therapies are currently available. The pharmacological treatment utilizes antidepressant drugs, such as selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants (TAs) and new multimodal antidepressants (NMAs). Non-pharmacological therapies include psychological interventions and non-invasive brain stimulation techniques, while excluding drug administration. In the general population experiencing PSD, SSRIs (sertraline in particular) are the most prescribed, whereas the combination of antidepressants and psychotherapy is underused. Furthermore, about one-third of patients do not receive treatment for PSD. In regard to older adults with PSD, the possibility of more adverse effects or contraindications to antidepressant prescription due to comorbidities may limit the therapeutic window. Although drugs such as citalopram, escitalopram, sertraline, venlafaxine, and vortioxetine are usually well tolerated by older patients with PSD, the few randomized controlled trials (RCTs) specifically considering older adults with PSD have been conducted with fluoxetine, fluvoxamine, reboxetine, citalopram and nortriptyline, often with very small patient samples. Furthermore, data regarding the results of non-pharmacological therapies are scarce. High-quality RCTs recruiting large samples of older adults are needed in order to better manage PSD in this population. In addition, adequate screening and diagnosis instruments, with reliable timing of evaluation, should be applied.

Increased C-Reactive Protein in Patients with Post-Stroke Depression: A Meta-analysis of Cohort Study

Background

Pathophysiological mechanisms and related biological markers for post-stroke depression (PSD) are unknown. Some studies have noted that C-reactive protein (CRP) is activated in the serum of PSD patients. We aim to quantitatively summarize the concentrations of CRP in PSD patients compared to non-PSD patients.

Methods

Original studies evaluating the association between CRP and PSD were searched in 4 specific databases from the establishment of the databases to March 2023. RevMan 5.20 and Stata 11.0 statistical software were used for meta-analysis. Publication bias was tested by Egger's test. The CRP level were combined by standardized mean difference (SMD) with 95% confidence interval (CI).

Results

A total of 43 relevant literatures were retrieved, while 13 cohort studies were collected. The heterogeneity test result of the level of CRP in patients with PSD vs. non-PSD was (Q = 98.38, P < .001, I2 = 88%). The combined value of the estimated effect was [SMD = 0.34, 95% CI (0.12-0.56); P = .003]. Sensitivity analysis indicated that no study had a remarkable influence on the result of the pooled estimate. Egger's test was used to test the bias and the result was (Egger's test, P = .548), suggesting that there was no publication bias, and the results were credible. We found that different depression evaluation criteria (P = .035) and stroke types (P = .024) were considered as influencing factors for potential sources of heterogeneity.

Conclusion

In conclusion, compared to those without depressive symptoms, patients with post-stroke depression have higher concentrations of CRP in the blood.

Association between baseline high-sensitive C-reactive protein, homocysteine levels, and post-stroke depression among stroke patients: a systematic review, meta-analysis, and meta-regression

BACKGROUND

Post-stroke depression (PSD) is a prevalent neuropsychiatric sequelae following stroke, often associated with diminished functional recovery and heightened mortality risk. Emerging evidence suggests neuroinflammation, triggered in response to stroke events, may be instrumental in precipitating PSD.

AIM

This study aims to assess the significance of high-sensitivity C-reactive protein (Hs-CRP) and homocysteine (Hcy) in post-stroke individuals with PSD.

METHODS

We systematically searched all electronic databases from inception until May 30, 2023. Outcomes were reported as standard mean difference (SMD), and their corresponding 95% confidence interval (95% CI).

RESULTS

A total of 12 studies with 3,230 patients were included in this study. The mean age of the overall cohort was 65.7 years, and patients with PSD were observed to be older than patients without PSD (68.3 years versus 63.1 years). We observed a higher female prevalence in the PSD group (44.4% versus 40.7%). PSD patients were more likely to be widowed (19.4% versus 8.4%) and more likely to have a family history of psychiatric disorder (11.3% versus 4.9%) compared to non-PSD patients. We also observed that patients with PSD had higher levels of baseline Hs-CRP [SMD 0.16, (95% CI 0.08 to 0.25), p<0.001], and Hcy [SMD 0.14, (95% CI 0.05 to 0.22), p<0.001] than patients without PSD. Meta-regression analysis did not reveal any effect modifier for higher Hs-CRP in the study group, however, history of widowhood was a significant effect modifier when assessing Hcy levels between the two groups (coefficient 1.998, p=0.038).

CONCLUSION

Baseline levels of Hs-CRP and Hcy were significantly higher in patients with PSD, highlighting the role of recognizing demographic and biochemical markers in understanding the complexities of post-stroke depression.

Associations of C-reactive protein with depressive symptoms over time after mild to moderate ischemic stroke in the PROSCIS-B cohort

BACKGROUND AND PURPOSE

C-reactive protein serves as a marker of inflammation and is linked to depression in the general population. We aimed to assess whether elevated baseline levels of high-sensitivity C-reactive protein (hs-CRP) are associated with depressive symptoms over time in a prospective cohort of mild-to-moderate first-ever ischemic stroke patients.

METHODS

Data were obtained from the Prospective Cohort with Incident Stroke Berlin (NCT01363856). Depressive symptoms were assessed with the Center for Epidemiologic Studies Depression Scale (CES-D) at three annual follow-up points. We assessed the association of elevated levels of hs-CRP with CES-D scores over time via linear mixed models. In a subgroup analysis, we explored an interaction effect with sex.

RESULTS

We included 585 ischemic stroke patients with baseline data on CRP levels. The mean age was 67 (13 SD), 39% (n = 226) were female, and the median National Institutes of Health Stroke Scale (NIHSS) was 3 (IQR 1-4). Twenty percent of survivors showed evidence for depressive symptoms one year after stroke with CES-D ≥ 16, 21% at year two, and 17% at year three. Higher log-transformed baseline hs-CRP levels were associated with higher CES-D Scores over time in the adjusted linear mixed model (β = 1.28; (95% CI 0.22-2.34)). The subgroup analysis revealed an interaction effect of hs-CRP on depressive symptoms in women (β = 2.33; (95% CI 0.71-3.95)).

CONCLUSION

In our cohort with mild-to-moderate first-ever ischemic stroke patients, hs-CRP levels were associated with more depressive symptoms over time, with an interaction effect for the female sex.

STUDY REGISTRATION

https://clinicaltrials.gov ; Unique identifier: NCT01363856.

Mechanisms of Maternal Diet-Induced Obesity Affecting the Offspring Brain and Development of Affective Disorders

Depression and metabolic disease are common disorders that share a bidirectional relationship and continue to increase in prevalence. Maternal diet and maternal behaviour both profoundly influence the developmental trajectory of offspring during the perinatal period. At an epidemiological level, both maternal depression and obesity during pregnancy have been shown to increase the risk of neuropsychiatric disease in the subsequent generation. Considerable progress has been made to understand the mechanisms by which maternal obesity disrupts the developing offspring gut-brain axis, priming offspring for the development of affective disorders. This review outlines such mechanisms in detail, including altered maternal care, the maternal microbiome, inflammation, breast milk composition, and maternal and placental metabolites. Subsequently, offspring may be prone to developing gut-brain interaction disorders with concomitant changes to brain energy metabolism, neurotransmission, and behaviour, alongside gut dysbiosis. The gut microbiome may act as a key modifiable, and therefore treatable, feature of the relationship between maternal obesity and the offspring brain function. Further studies examining the relationship between maternal nutrition, the maternal microbiome and metabolites, and offspring neurodevelopment are warranted to identify novel therapeutic targets.

Association between C-reactive protein levels and development of post-stroke depression: A systematic review and meta-analysis

BACKGROUND AND AIMS

Different prospective cohort studies have focused on the C-reactive protein (ie, a pentameric protein) biomarker as a predictor of post-stroke depression. In this review and meta-analysis, we will attempt to synthesize the evidence for the association between C-reactive protein and the development of post-stroke depression.

METHODS

We systematically searched five academic databases for relevant studies according to the PRISMA guidelines. We evaluate the comparative levels of C-reactive protein in patients with stroke and/without depression, and analyzed the hazard ratio to evaluate the overall risk of C-reactive protein levels in patients with stroke.

RESULTS

We selected eligible studies with 2534 patients (mean age: 65.2  ±  5.9 years) from the initial 10 926 studies in the databases. Increased C-reactive protein levels (Hedge's g, 0.84) in patients with stroke and depression as compared to patients with stroke without depression. Increased levels of C-reactive protein were associated with the onset of depression (Hazard's ratio, 1.6) in patients with stroke.

CONCLUSION

Our findings provide an association of C-reactive protein with the development of post-stroke depression, and present higher levels than patients with stroke without depression. Additionally, our findings support the role of C-reactive protein levels as markers for predicting depression in patients with stroke.

The potential risk factors of early-onset post-stroke depression from immuno-inflammatory perspective

Background

Mounting evidence strongly uncovered that peripheral immuno-inflammatory response induced by acute stroke is associated with the appearance of post-stroke depression (PSD), but the mechanism remains unclear.

Methods

103 stroke patients were assessed at 2 weeks after onset using Diagnostic and Statistical Manual of Mental Disorders, 5th edition and then divided into PSD and non-PSD groups. Polymorphisms of inflammatory molecules (interleukin [IL]-1β, IL-6, IL-10, IL-18, tumor necrosis factor-α [TNF-α], interferon-γ [IFN-γ] and C-reactive protein [CRP]), complete blood count parameters, splenic attenuation (SA) and splenic volume (SV) on unenhanced chest computed tomography, demographic and other clinical characteristics were obtained. Binary logistic regression model was used to analyze the associations between inflammation-related factors and the occurrence of PSD at 2 weeks after stroke.

Results

49 patients were diagnosed with PSD at 2 weeks after onset (early-onset PSD). The C/T genotypes of CRP rs2794520 and rs1205 were less in PSD group than non-PSD group (both adjusted odds ratio = 3.364; 95%CI: 1.039-10.898; p = 0.043). For CRP rs3091244, the frequency of G allele was higher (80.61% vs. 13.89%) while the frequency of A allele was lower (6.12% vs. 71.30%) in PSD patients than non-PSD patients (χ² = 104.380; p<0.001). SA of PSD patients was lower than that of non-PSD patients in the presence of CRP rs2794520 C/T genotype and rs1205 C/T genotype (both t = 2.122; p = 0.039). Peripheral monocyte count was less in PSD group than non-PSD group (adjusted odds ratio = 0.057; 95%CI: 0.005-0.686; p = 0.024).

Conclusions

CRP polymorphisms, SA based on CRP genotype, and peripheral monocytes are associated with the risk of early-onset PSD, suggesting peripheral immuno-inflammatory activities elicited by stroke in its aetiology.

Neutrophil to Lymphocyte Ratio and Platelet to Lymphocyte Ratio in Poststroke Depression: A Systematic Review and Meta-Analysis

Objectives. Evidence shows that stroke-induced inflammatory responses play an essential role in the development of poststroke depression (PSD). The goal of this systematic review and meta-analysis was to critically evaluate the literature regarding the use of the neutrophil to lymphocyte ratio (NLR) as a reliable means to detect early PSD development, to help clinicians institute early interventions and improve outcomes. Methods. Electronic databases, including Web of Science, PubMed, Google Scholar, and Scopus, were searched, and eight studies were included. We assessed the certainty of the associations with GRADE methods. Results. We found that patients with PSD had higher NLR than the stroke patients with no depression ( $\text{SMD}=0.51$ ; $\text{CI}95\%=0.29$ -0.73, $p<0.001$ ). Also, we found a significantly higher PLR in the patients with PSD when compared to the stroke patients with no depression ( $\text{SMD}=0.66$ ; $\text{CI}95\%=0.19$ -1.13, $p<0.001$ ). Conclusion. These findings indicated that NLR and PLR could be considered inexpensive biomarkers for the prediction of PSD.

Higher Plasma Fibrinogen Level at Admission Is Associated with Post-Stroke Depression at Discharge

Background: Post-stroke depression (PSD) is a common complication of stroke, which seriously affects the functional outcome of patients. Systemic low-grade inflammation associated with PSD has been shown to occur at several months to years, however, whether these inflammatory markers predicted PSD at an acute stage of stroke is controversial. Method: A total of 625 patients with acute ischemic stroke (219 female, 35.40%) were included in this study. PSD was diagnosed using the 17-item Hamilton depression scale (HAMD) at 7 days following discharge (7−14 days after stroke onset). Multivariable logistic regression analysis was applied to build a prediction model for PSD at discharge. Discrimination and calibration of the model were assessed by C-index, calibration plot. Internal validation was conducted using bootstrapping validation. Results: At discharge of hospitalization, 95 patients (15.20%) were diagnosed with PSD. Multivariable logistic regression suggested that female gender (OR = 2.043, 95% CI = 1.287−3.245, p = 0.002), baseline NIHSS (OR = 1.108, 95% CI = 1.055−1.165, p < 0.001) and fibrinogen (OR = 1.388, 95% CI = 1.129−1.706, p = 0.002) were independent predictors for PSD at discharge. The cut-off of the fibrinogen plasma level was 3.08 g/L. These predictors were included in the nomogram. The model displayed good discrimination, with a C-index of 0.730 (95% CI = 0.683−0.777) and good calibration. Conclusion: Female gender, baseline stroke severity and a higher level of fibrinogen were independently associated with PSD at discharge. A nomogram based on these three predictors can be used to provide an individual, visual prediction of the risk probability of PSD.

Symptomatic plaque enhancement is associated with early-onset post-stroke depression

BACKGROUND

The association between imaging features closely associated with symptomatic intracranial atherosclerotic plaques and early-onset post-stroke depression (PSD) is currently unclear.

MATERIALS AND METHODS

76 ischemic stroke patients who underwent high-resolution vessel wall magnetic resonance imaging (HR-VWI) were divided into PSD and non-PSD groups according to their DSM-V diagnoses and HAMD-17 scores at 14 days after onset. Clinical data and the imaging features associated with symptomatic plaques (including the enhancement index (EI), remodeling index, and plaque surface irregularity) were compared between groups. Multifactorial logistic regression analysis was used to find independent predictors of early-onset PSD. Spearman rank correlation analysis explores the association between clinical data, symptomatic plaque imaging features, and HAMD-17 in patients.

RESULTS

The sample comprised 36 patients with early-onset PSD. The symptomatic plaque EI and infarct volume were significantly higher in depressed patients than in patients without depression (P < 0.05). Multivariate logistic regression showed that symptomatic plaque EI could be used as an independent predictor of early-onset PSD after correcting for the confounding factor of infarct volume (OR = 1.034, 95% CI:1.014-1.055, P = 0.001). In the total sample, symptomatic plaque EI, infarct volume, and HAMD-17 had a significant positive correlation with each other (P < 0.05).

LIMITATIONS

This study focused only on the patients' symptomatic plaques and did not monitor patients' systemic inflammation levels at the time of HR-VWI.

CONCLUSIONS

The degree of symptomatic plaque enhancement is an independent predictive imaging marker of early-onset PSD and can be used the early diagnosis of early-onset PSD.

Elevated Red Blood Cell Distribution Width Levels at Admission Predicts Depression After Acute Ischemic Stroke: A 3-Month Follow-Up Study

PURPOSE

Red blood cell distribution width (RDW) is closely related to inflammatory-related disease markers. The present study aimed to investigate the association between the red blood cell distribution width (RDW) and post-stroke depression (PSD).

PATIENTS AND METHODS

A total of 414 patients with acute ischemic stroke (AIS) admitted to our hospital from June 2018 to July 2021 were consecutively enrolled and received 3 months' follow-up. According to the 17-item Hamilton Depression Scale (HAMD) assessment, they were divided into PSD group and non-PSD group. Diagnosis of PSD was made in accordance with DSM-IV. RDW was recorded within 24 hours of admission.

RESULTS

Among the included 414 patients, 95 (22.95%) patients were diagnosed as having PSD at 3 months after stroke. The results showed significantly higher level of RDW in patients with depression (13.69 (IQR13.24-13.88) vs. 13.56 (IQR 12.67-13.77), P<0.001) at admission than patients without depression. After adjustment for potential confounding factors, the odds ratio of PSD was 5.707 (95% CI, 2.717-11.989) for the highest tertile of RDW compared with the lowest tertile. Moreover, based on the receiver operating characteristic (ROC) curve, the optimal cutoff of RDW levels as an indicator for the prediction of PSD was projected as 13.01, which yielded a sensitivity of 83% and a specificity of 41.0%, with an area under the curve (AUC) of 0.643 (95% CI, 0.585-0.701; P = 0.012).

CONCLUSION

Higher RDW levels at admission were found to be correlated with PSD 3 months after stroke.

Higher levels of C-reactive protein in the acute phase of stroke indicate an increased risk for post-stroke depression: A systematic review and meta-analysis

BACKGROUND

Investigations have revealed the association between inflammation and post-stroke depression (PSD). However, whether the C-reactive protein (CRP) level, a biomarker of inflammation, would affect the development of PSD is still controversial.

METHODS

A systematic search of databases was performed for eligible studies. Standardized Mean Difference (SMD) with 95 % Confidence Interval (CI) was used to assess the association between the CRP level in the acute phase of stroke and the risk of PSD.

RESULTS

13 cohort studies that involved 3536 participants were included. Combined results showed that compared with non-PSD patients, the CRP level of PSD patients was significantly higher on admission (SMD = 0.19, 95 % CI: 0.12-0.27). A subgroup analysis by classifying the assessment time of depression showed obvious differences of the CRP levels between the PSD patients who were diagnosed more than 1 month after stroke and the non-PSD (1-3 months: SMD = 0.16, 95 % CI: 0.06-0.25; >3months: SMD = 0.34, 95 % CI: 0.18-0.51).

CONCLUSION

A higher level of CRP in the acute phase of stroke suggests an increased risk for PSD.

Association of early and later depressive symptoms with functional outcome after ischemic stroke

Background

Post-stroke depressive symptoms (DS) can be chronic or transient, occurring shortly or long after stroke and lasting only few months. It remains unclear if the prognosis differs between patients with DS in the acute phase of stroke and those who develop DS several months later. We aimed to determine whether outcomes vary among patients with different trajectories of post-stroke depressive symptoms.

Methods

Of 698 enrolled patients with ischemic stroke, we included 335 participants (median age: 68, 48% female) who were assessed for DS both 8 days and 3 months post-stroke. We divided patients into 4 groups: without greater DS (Group 1), only earlier DS (Group 2), only later DS (Group 3), and persistent DS (Group 4). Logistic regression was used to determine the association between DS and 3- and 12-month functional outcome.

Results

Group 2 was predominantly female and had the highest rate of previous stroke or transient ischemic attack. Group 3 was more likely to suffer from delirium and more severe stroke. Group 4 had the highest frequency of vascular risk factors, pre-morbid psychiatric symptoms, and cognitive decline. In multivariate analysis, Group 3, but not Groups 2 and 4, had an increased risk of poor 3- and 12-month functional outcome (adjusted OR 2.59, 95% CI 1.64–4.07, P < 0.01 and OR 3.97, 95% CI 2.32–6.76, P < 0.01, respectively) compared with Group 1.

Conclusions

Different trajectories of post-stroke DS are related to different outcomes. Patients who only have later DS also have the worst prognosis.

Early Depression Independently of Other Neuropsychiatric Conditions, Influences Disability and Mortality after Stroke (Research Study-Part of PROPOLIS Study)

Post-stroke depression (PSD) is the most frequent neuropsychiatric consequence of stroke. The nature of the relationship between PSD and mortality still remains unknown. One hypothesis is that PSD could be more frequent in those patients who are more vulnerable to physical disability, a mediator variable for higher level of physical damage related to higher risk of mortality. Therefore, the authors' objective was to explore the assumption that PSD increases disability after stroke, and secondly, that mortality is higher among patients with PSD regardless of stroke severity and other neuropsychiatric conditions. We included 524 consecutive patients with acute stroke or transient ischemic attack, who were screened for depression between 7-10 days after stroke onset. Physical impairment and death were the outcomes measures at evaluation check points three and 12 months post-stroke. PSD independently increased the level of disability three (OR = 1.94, 95% CI 1.31-2.87, p = 0.001), and 12 months post-stroke (OR = 1.61, 95% CI 1.14-2.48, p = 0.009). PSD was also an independent risk factor for death three (OR = 5.68, 95% CI 1.58-20.37, p = 0.008) and 12 months after stroke (OR = 4.53, 95% CI 2.06-9.94, p = 0.001). Our study shows the negative impact of early PSD on the level of disability and survival rates during first year after stroke and supports the assumption that depression may act as an independent mediator for disability leading to death in patients who are more vulnerable for brain injury.

Post-inflammatory behavioural despair in male mice is associated with reduced cortical glutamate-glutamine ratios, and circulating lipid and energy metabolites

Post-inflammatory behaviours in rodents are widely used to model human depression and to test the efficacy of novel anti-depressants. Mice injected with lipopolysaccharide (LPS) display a depressive-like phenotype twenty-four hours after endotoxin administration. Despite the widespread use of this model, the mechanisms that underlie the persistent behavioural changes after the transient peripheral inflammatory response remain elusive. The study of the metabolome, the collection of all the small molecule metabolites in a sample, combined with multivariate statistical techniques provides a way of studying biochemical pathways influenced by an LPS challenge. Adult male CD-1 mice received an intraperitoneal injection of either LPS (0.83 mg/kg) or saline, and were assessed for depressive-like behaviour 24 h later. In a separate mouse cohort, pro-inflammatory cytokine gene expression and 1H nuclear magnetic resonance (NMR) metabolomics measurements were made in brain tissue and blood. Statistical analyses included Independent Sample t-tests for gene expression data, and supervised multi-variate analysis using orthogonal partial least squares discriminant analysis for metabolomics. Both plasma and brain metabolites in male mice were altered following a single peripheral LPS challenge that led to depressive-like behaviour in the forced swim test. The plasma metabolites altered by LPS are involved in energy metabolism, including lipoproteins, glucose, creatine, and isoleucine. In the brain, glutamate, serine, and N-acetylaspartate (NAA) were reduced after LPS, whereas glutamine was increased. Serine-modulated glutamatergic signalling and changes in bioenergetics may mediate the behavioural phenotype induced by LPS. In light of other data supporting a central imbalance of glutamate-glutamine cycling in depression, our results suggest that aberrant central glutaminergic signalling may underpin the depressive-like behaviours that result from both inflammation and non-immune pathophysiology. Normalising glutaminergic signalling, rather than seeking to increase serotonergic signalling, might prove to be a more coherent approach to the development of new treatments for mood disorder.