Recovery from major depressive disorder episode after non-pharmacological treatment is associated with normalized cytokine levels

Paradoxical effect of anti-inflammatory drugs on IL-6 mRNA expression in patients with PTSD during treatment

The pathophysiology of posttraumatic stress disorder (PTSD) is associated with the activation of the innate immune system, including cytokines like interleukin 6 (IL-6). However, the role of IL-6 in the etiology and treatment of PTSD still remains elusive. We conducted a prospective controlled trial to investigate the development of IL-6 during psychosomatic treatment in individuals with PTSD in comparison with individuals without PTSD. We assessed IL-6 mRNA expression before and after 2 months of psychosomatic treatment in individuals with and without PTSD. Severities of PTSD and depressive symptoms were assessed in parallel. Linear mixed regression was applied for statistical analysis, including the factors diagnosis PTSD and pre-post treatment after subgrouping for intake of anti-inflammatory drugs. The development of IL-6 mRNA expression during treatment was affected by the use of anti-inflammatory drugs. In the subgroup without intake of anti-inflammatory drugs, no significant statistical treatment effect in individuals with and without PTSD emerged. In the subgroup of individuals taking anti-inflammatory drugs, a significant interaction effect of the factors pre-post treatment and diagnosis PTSD was observed. Whereas IL-6 mRNA expression in individuals without PTSD decreased according to amelioration of symptoms, IL-6 mRNA expression in individuals with PTSD increased significantly during treatment, in opposite direction to symptom severity. Anti-inflammatory drugs might affect IL-6 mRNA expression in individuals with PTSD in a paradoxical way. This study offers a further piece of evidence that IL-6 could be involved in the pathophysiology of PTSD and PTSD-specific immunologic molecular mechanisms.

Changes in pain during a depressive episode and relationship to cytokine levels in major depressive disorder

BACKGROUND

Depressed patients have an increased incidence of pain. A pathophysiological connection between depression and pain is still not revealed. Immunological activation has been found in both depression and pain. There are few studies of pain and immune activation in patients with depression, without inflammatory and autoimmune disorders.

METHODS

This is a naturalistic follow-up study of 50 patients with a major depressive disorder (MDD) depressive episode, without any inflammatory or autoimmune conditions. We have previously reported on the relationship between depression and cytokine levels. In this study, we obtained data of depression, pain and cytokine levels before and after 12 weeks of depression treatment. All patients were medication-free at inclusion.

RESULTS

At inclusion three out of four patients experienced pain, and the pain scores correlated with the depression scores. After treatment, as depression was relieved, the pain scores dropped significantly and were no longer correlated to the depression scores. There were no correlations between pain scores and cytokine levels. Pain level at inclusion did not correlate with depression treatment outcome.

CONCLUSION

Our findings indicate that pain is a feature of depression. Pain levels and cytokine values didn't correlate. Pain at inclusion did not predict depression treatment outcome.

The role of T-lymphocytes in central nervous system diseases

The central nervous system (CNS) has been considered an immunologically privileged site. In the past few decades, research on inflammation in CNS diseases has mostly focused on microglia, innate immune cells that respond rapidly to injury and infection to maintain CNS homeostasis. Discoveries of lymphatic vessels within the dura mater and peripheral immune cells in the meningeal layer indicate that the peripheral immune system can monitor and intervene in the CNS. This review summarizes recent advances in the involvement of T lymphocytes in multiple CNS diseases, including brain injury, neurodegenerative diseases, and psychiatric disorders. It emphasizes that a deep understanding of the pathogenesis of CNS diseases requires intimate knowledge of T lymphocytes. Aiming to promote a better understanding of the relationship between the immune system and CNS and facilitate the development of therapeutic strategies targeting T lymphocytes in neurological diseases.

Preliminary results of anti-inflammatory cytokine concentrations predicting therapy outcome in panic disorder

Background

Patients with panic disorder (PD) show alterations of the immune reactivity to acute stress, which could serve as a marker for effective treatment. Nevertheless, the effect of immune reactivity under acute stress before treatment on therapy outcome remains unclear.

Methods

A total of N = 16 PD patients performed the Trier Social Test. Blood sample collection of anti-inflammatory cytokine IL-10 accompanied the TSST. The Mobility Inventory was handed out for the assessment of avoidance behavior before and after treatment. Area under the curve with respect to the ground (AUCG) and increase (AUCI) were calculated for assessed cytokine levels and were used as predictors for therapy outcome in regression analyses.

Results

AUCG significantly predicts avoidance behavior in company after treatment (β = -0.007, p = .033) but not avoidance behavior alone (β = -0.003, p = .264). AUCI does not significantly predict therapy outcome.

Conclusion

Higher concentrations of anti-inflammatory cytokine IL-10 under acute stress before treatment predicts less avoidance behavior in company after therapy. Immune markers seem to play a crucial role in the maintenance of mental disorders such as PD. Underlying mechanisms and IL-10 as a marker for individualized treatments should be investigated in future studies.

Clinical Spectrum and Trajectory of Innovative Therapeutic Interventions for Insomnia: A Perspective

Increasing incidences of insomnia in adults, as well as the aging population, have been reported for their negative impact on the quality of life. Insomnia episodes may be associated with neurocognitive, musculoskeletal, cardiovascular, gastrointestinal, renal, hepatic, and metabolic disorders. Epidemiological evidence also revealed the association of insomnia with oncologic and asthmatic complications, which has been indicated as bidirectional. Two therapeutic approaches including cognitive behavioral therapy (CBT) and drugs-based therapies are being practiced for a long time. However, the adverse events associated with drugs limit their wide and long-term application. Further, Traditional Chinese medicine, acupressure, and pulsed magnetic field therapy may also provide therapeutic relief. Notably, the recently introduced cryotherapy has been demonstrated as a potential candidate for insomnia which could reduce pain, by suppressing oxidative stress and inflammation. It seems that the synergistic therapeutic approach of cryotherapy and the above-mentioned approaches might offer promising prospects to further improve efficacy and safety. Considering these facts, this perspective presents a comprehensive summary of recent advances in pathological aetiologies of insomnia including COVID-19, and its therapeutic management with a greater emphasis on cryotherapy.

Increased immuno-inflammatory mediators in women with post-traumatic stress disorder after sexual assault: 1-Year follow-up

BACKGROUND

Sexual violence is a traumatic event that can trigger post-traumatic stress disorder (PTSD) and generate biological responses to stress characterized by inhibiting the hypothalamic-pituitary axis (HPA), altering immune activity, and changing the structure and function of the brain. PTSD is associated with increased levels of inflammatory markers. This study aimed to measure differences in inflammatory markers and HPA hormone levels between women with PTSD due to sexual violence and controls at baseline and after 1-year follow-up.

METHODS

Fifty-eight women with PTSD resulting from sexual assault occurring up to 6 months prior were compared to 41 female controls. The patients were followed for 1 year. At baseline (T1), we measured inflammatory biomarkers. We also applied the Mini International Neuropsychiatric Interview (MINI), the Clinician-Administered Post-Traumatic Stress Disorder Scale-5, the Beck Depression Inventory, the Beck Anxiety Inventory, and the Childhood Trauma Questionnaire. The patients were randomized to receive treatment with sertraline or interpersonal psychotherapy for 14 weeks (T2) and then continued the usual treatment if deemed necessary for 1 year. The same interviews and examinations were repeated after 1 year (T3).

RESULTS

At baseline, the patients had significantly higher adrenocorticotropic hormone levels, compared to controls; however, there was no baseline difference in inflammatory markers or cortisol. After 1 year, there were significantly higher levels of interleukin-1β (p < 0.0001), monocyte chemoattractant protein-1 (p < 0.0001), tumor necrosis factor-α (p < 0.0001), c-reactive protein (p < 0.0001), and cortisol (p = 0.046) in the patient group. In addition to PTSD, 56 patients presented with a major depressive episode at T1 (according to the MINI). At the end of 1 year, there was a significant improvement in depressive (p < 0.001), anxiety (p = 0.03), and PTSD symptoms (p < 0.001) regardless of the treatment received.

DISCUSSION

The increase of the inflammatory markers after 1 year, even with symptomatic improvement, may indicate that PTSD following sexual violence is associated with high depressive symptoms. This association may have a different pattern of immunoendocrine alterations than PTSD only. Furthermore, these alterations may persist in the long term, even with the improvement of the symptoms, probably generating an immunological imprint that can lead to future clinical consequences. This study adds to the current knowledge of PTSD neurobiology and contributes to broadening approaches to this disorder.

Current Perspectives on Pharmacological and Non-Pharmacological Interventions for the Inflammatory Mechanism of Unipolar Depression

Since depression remains a major public health issue there is a constant need for new and more efficient therapeutic strategies based on the mechanisms involved in the aetiology of depression. Thus, the pathogenic link between depression and inflammation is considered to play a potential key role in the development of such therapies. This review summarizes the results of various pharmacological (non-steroidal anti-inflammatory drugs, aspirin, cyclooxygenase inhibitors, cytokine inhibitors, corticosteroids, statins, minocycline, N-acetyl cysteine, omega-3 fatty acids and probiotics) and non-pharmacological interventions (electroconvulsive therapy, physical exercise and psychological therapy) and outlines their efficacy and discusses potential challenges. Both conventional and non-conventional anti-inflammatory drugs showed promising results according to the specific group of patients. The pre-existing pro-inflammatory status was, in most cases, a predictor for clinical efficacy and, in some cases, a correlation between clinical improvement and changes in various biomarkers was found. Some of the non-pharmacological interventions (physical exercise and electroconvulsive therapy) have also showed beneficial effects for depressive patients with elevated inflammatory markers. Treatments with anti-inflammatory action may improve clinical outcomes in depression, at least for some categories of patients, thus opening the way for a future personalised approach to patients with unipolar depression regarding the inflammation-related mechanism.

Behavioral activation therapy for depression is associated with a reduction in the concentration of circulating quinolinic acid

BACKGROUND

An inflammation-induced imbalance in the kynurenine pathway (KP) has been reported in major depressive disorder but the utility of these metabolites as predictive or therapeutic biomarkers of behavioral activation (BA) therapy is unknown.

METHODS

Serum samples were provided by 56 depressed individuals before BA therapy and 29 of these individuals also provided samples after 10 weeks of therapy to measure cytokines and KP metabolites. The PROMIS Depression Scale (PROMIS-D) and the Sheehan Disability Scale were administered weekly and the Beck depression inventory was administered pre- and post-therapy. Data were analyzed with linear mixed-effect, general linear, and logistic regression models. The primary outcome for the biomarker analyses was the ratio of kynurenic acid to quinolinic acid (KynA/QA).

RESULTS

BA decreased depression and disability scores (p's < 0.001, Cohen's d's > 0.5). KynA/QA significantly increased at post-therapy relative to baseline (p < 0.001, d = 2.2), an effect driven by a decrease in QA post-therapy (p < 0.001, uncorrected, d = 3.39). A trend towards a decrease in the ratio of kynurenine to tryptophan (KYN/TRP) was also observed (p = 0.054, uncorrected, d = 0.78). Neither the change in KynA/QA, nor baseline KynA/QA were associated with response to BA therapy.

CONCLUSION

The current findings together with previous research show that electronconvulsive therapy, escitalopram, and ketamine decrease concentrations of the neurotoxin, QA, raise the possibility that a common therapeutic mechanism underlies diverse forms of anti-depressant treatment but future controlled studies are needed to test this hypothesis.

Increased serum resistin but not G-CSF levels are associated in the pathophysiology of major depressive disorder: Findings from a case-control study

Background

Many studies have predicted major depressive disorder (MDD) as the leading cause of global health by 2030 due to its high prevalence, disability, and illness. However, the actual pathophysiological mechanism behind depression is unknown. Scientists consider alterations in cytokines might be tools for understanding the pathogenesis and treatment of MDD. Several past studies on several inflammatory cytokine expressions in MDD reveal that an inflammatory process is activated, although the precise causes of that changes in cytokine levels are unclear. Therefore, we aimed to investigate resistin and G-CSF in MDD patients and controls to explore their role in the pathogenesis and development of depression.

Methods

We included 220 participants in this study. Among them, 108 MDD patients and 112 age-sex matched healthy control (HCs). We used DSM-5 to evaluate study participants. Also, we applied the Ham-D rating scale to assess the severity of patients. Serum resistin and G-CSF levels were measured using ELISA kits (BosterBio, USA).

Results

The present study observed increased serum resistin levels in MDD patients compared to HCs (13.82 ± 1.24ng/mL and 6.35 ± 0.51ng/mL, p <0.001). However, we did not find such changes for serum G-CSF levels between the groups. Ham-D scores showed a significant correlation with serum resistin levels but not G-CSF levels in the patient group. Furthermore, ROC analysis showed a fairly predictive performance of serum resistin levels in major depression (AUC = 0.746).

Conclusion

The present study findings suggest higher serum resistin levels are associated with the pathophysiology of MDD. This elevated serum resistin level may serve as an early risk assessment indicator for MDD. However, the role of serum G-CSF in the development of MDD is still unclear despite its neuroprotective and anti-inflammatory effects.

Effects of antidepressant drug therapy with or without physical exercise on inflammatory biomarkers in major depressive disorder: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To conduct a systematic review and meta-analysis of the effects of antidepressant drug therapy (with or without physical exercise) on peripheral inflammatory markers in patients with major depressive disorder (MDD).

METHODS

MEDLINE, PyscINFO, Embase, and Google Scholar databases were searched until May 2020. Randomized trials that measured at least one inflammatory biomarker and included adult outpatients with MDD under antidepressant drug therapy (any drug) with or without physical exercise (any modality) were eligible. Results were summarized using the standardized mean difference (SMD) with 95% confidence intervals (95% CI) under a random-effects model. The Cochrane risk of bias tool (2010) was used to evaluate the risk of bias in the included trials.

RESULTS

Sixty-three trials were identified, encompassing data from 3482 patients, and 20 investigated biomarkers. Trials had biases across multiple domains, rising concerns primarily to selection bias/performance bias/detection bias/attrition bias. SMDs between pre- and post-results indicated a significant reduction in the levels of IL-2 (SMD, - 0.25; 95% CI, - 0.41 to - 0.09, P = 0.002), IL-6 (SMD, - 0.19; 95% CI, - 0.35 to - 0.025, P = 0.024), IL-10 (SMD, - 0.32; 95% CI, - 0.57 to - 0.07, P = 0.011), and serum cortisol (SMD, - 0.35; 95% CI, - 0.58 to - 0.12, P = 0.002). Evidence supporting the influence of physical exercise combined with antidepressant drugs on peripheral inflammatory markers in MDD is sparse and heterogeneous.

CONCLUSION

There is some evidence that antidepressant drug therapy is associated with an overall positive reduction in inflammatory markers, but the evidence is heterogeneous. Further research linking how inflammatory biomarkers modulate physiology related to antidepressant response is required.

TRIAL REGISTRATION

CRD42020220735.

The Immunology of Stress and the Impact of Inflammation on the Brain and Behavior

Exposure to acute versus chronic stressors and threats activates the immune system in adaptive and maladaptive manners, respectively. While acute activation of the immune system in response to threat is homeostatically regulated by glucocorticoid negative feedback, chronic activation of the immune system arising from persistent stress exposure can contribute to an allostatic load with an inflammatory diathesis that has been implicated in stress-related psychopathology, including of depression and anxiety. Increased inflammation in the periphery and in the brain arising from chronic stress exposure can alter neurotransmitter metabolism and impact activation of brain regions to increase adverse behavioral health symptoms (e.g. anhedonia, anxiety, fatigue) and emotion dysregulation. While interventions targeting the immune system and its downstream effects on the brain for the treatment of depression and other psychiatric disorders has been of great interest as they have shown some efficacy in treating stress-related behavioral health disorders, future studies are necessary to better characterize the contexts under which anti-inflammatory agents should be used to treat stress-related psychopathology.

Cytokines changes associated with electroconvulsive therapy in patients with treatment-resistant depression: a Meta-analysis

One third of depressive patients do not achieve remission after several steps of treatment and are considered as treatment resistant. Electroconvulsive therapy (ECT) improves symptoms in 70 to 90% of such cases. Resistant depression is associated with a dysregulation of the immune system with a dysbalance between the pro- and the anti-inflammatory cytokines. Therefore, we aimed to measure the kinetic of cytokines levels before, during and at the end of ECT. To test this hypothesis, we performed a meta-analysis assessing cytokines plasma levels before, during and after ECT in patients with major depressive disorders. After a systematic database search, means and standard deviations were extracted to calculate standardized mean differences. We found that IL-6 levels increased after 1 or 2 ECT session (p = 0.01) then decrease after 4 ECT sessions (p < 0.01) with no difference at the end of ECT (p = 0.94). A small number of studies were included and there was heterogeneity across them. The present meta-analysis reveals that ECT induces an initial increase of IL-6 levels and a potential decrease of TNF-α levels. No changes on IL-4 and IL-10 levels were found. Further work is necessary to clarify the impact of ECT on peripheral cytokines.

A longitudinal analysis of cytokines in anorexia nervosa

OBJECTIVE

Inflammation has been proposed to have a pathophysiological role in anorexia nervosa (AN) and to contribute to the maintenance of the disorder. Longitudinal cytokine research in AN has focused on only a few pro-inflammatory cytokines. We assessed a broad range of cytokines over time in people undergoing specialised treatment for AN.

METHOD

We measured serum concentrations of 27 cytokines in people with AN (n = 23). Body mass index (BMI), eating disorder (ED) symptoms and general psychopathology were assessed and blood samples were collected within four weeks of the commencement of specialised ED treatment (baseline) and at 12- and 24-week follow-ups.

RESULTS

Both BMI and ED symptoms improved over the assessment period. Linear mixed models showed that log IL-6 decreased between baseline and week 12 assessments. By week 12, log IL-6 values were comparable to levels in healthy individuals. Log IL-7 increased from week 12 to week 24.

DISCUSSION

Initially elevated IL-6 serum concentrations appear to 'normalize' during the first 3-months of specialised treatment for AN and this co-occurs with improvements in ED symptoms. Therefore, IL-6 has the potential to be a state biomarker for AN.

The effect of combined treatment with SSRIs and renin-angiotensin system (RAS) drugs: A propensity score matched cohort study

Drugs acting on the renin-angiotensin system (RAS) may have beneficial effects on mental health. We investigated whether use of drugs acting on the RAS, as add-on to selective serotonin reuptake inhibitors (SSRIs), was associated with a reduced risk of psychiatric hospital contacts. We identified all individuals initiating treatment with an SSRI between 1997 and 2012. Individuals using an SSRI without concomitant use of a RAS drug (SSRI-only users) were propensity score matched 1:1 to individuals using both an SSRI and a drug acting on the RAS (SSRI+RAS users). The SSRI-only and SSRI+RAS users were followed for up to three years or until December 31, 2013. We performed Cox proportional hazard regression analyses to calculate risks for psychiatric hospital contacts, hospital contacts due to depression, suicidal behavior, and all-cause mortality. We followed 30,311 SSRI-only users and 30,311 SSRI+RAS users for a total of 49,327 person-years. Compared to SSRI-only users, concomitant use of SSRI+RAS was associated with a significantly reduced risk for psychiatric hospital contacts (hazard rate ratio (HRR)=0.91; 95%-confidence intervals (95%-CI)=0.84-0.98) and lower mortality rate (HRR=0.70; 95%-CI=0.66-0.75). The associations between SSRI+RAS use and psychiatric hospital contacts for depression (HRR=0.92; 95%-CI=0.80-1.05) and suicidal behavior (HRR=1.06; 95%-CI=0.79-1.42) were not statistically significant. In this observational cohort study, concomitant use of an SSRI and a drug acting on the RAS was associated with a slightly reduced risk for psychiatric hospital contacts, when compared to use of an SSRI alone.

Inflammatory cytokines in patients with common mental disorders treated with cognitive behavior therapy

Peripheral inflammation has been found associated with psychiatric disorders. However, results are inconclusive as to its role in common mental disorders (CMDs), i.e., depression, anxiety, insomnia and stress-related disorders. Further, some research suggests that cognitive behavior therapy (CBT) could reduce inflammatory markers in CMDs. In the present study, we measured pro-inflammatory cytokines (tumor necrosis factor alpha [TNF-α], interleukin-6 [IL-6] and IL-8) pre- and post-treatment in two clinical trials (N ​= ​367) investigating CBT for patients with CMDs in primary care. We hypothesized that higher levels of these cytokines would be associated with more severe psychiatric symptoms (i.e., symptoms of depression, stress and anxiety). We also hypothesized that level of cytokines would decrease after CBT and that the reduced levels would correlate with a reduction in symptoms. Results showed that in men, higher levels of TNF-α were associated with more severe psychiatric symptoms. Further, age moderated the association between TNF-α, as well as IL-6, and stress, and exploratory stratified analyses revealed significant associations in subgroups. No other significant associations between cytokines and psychiatric symptoms were found. None of the cytokines were reduced following CBT, and the marked improvements in psychiatric symptoms after treatment were not associated with changes in cytokines. In conclusion, although inflammation might be of relevance in subgroups, it seems to be of limited importance for clinical improvements across mild to moderate CMDs.

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Immune dysregulation has been implicated in the etiology of common mental disorders.

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Pro-inflammatory cytokines were measured pre and post cognitive behavior therapy.

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Baseline associations between cytokines and symptoms were only found in subgroups.

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Cytokine levels (TNF-α, IL-6 and IL-8) were not reduced after treatment.

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Symptom improvement was not accompanied by reductions in cytokine levels.

Cytokine concentrations are related to level of mental distress in inpatients not using anti-inflammatory drugs

OBJECTIVE

Cross-sectional data show elevated levels of circulating cytokines in psychiatric patients. The literature is divided concerning anti-inflammatory drugs' ability to relieve symptoms, questioning a causal link between inflammatory pathways and psychiatric conditions. We hypothesised that the development of circulating cytokine levels is related to mental distress, and that this relationship is affected by the use of anti-inflammatory drugs.

METHODS

The study was a longitudinal assessment of 12-week inpatient treatment at Modum Bad Psychiatric Center, Norway. Sera and self-reported Global Severity Index (GSI) scores, which measure psychological distress, were collected at admission (T0), halfway (T1) and before discharge (T2). Other variables known to distort the neuroimmune interplay were included. These were age, gender, diagnosis of PTSD, antidepressants and anti-inflammatory drugs. A total of 128 patients (92 women and 36 men) were included, and 28 were using anti-inflammatory medication. Multilevel modelling was used for data analysis.

RESULTS

Patients with higher levels of IL-1RA and MCP-1 had higher GSI scores (p = 0.005 and p = 0.020). PTSD patients scored higher on GSI than non-PTSD patients (p = 0.002). These relationships were mostly present among those not using anti-inflammatory drugs (n = 99), with higher levels of IL-1RA and MCP-1 being related to higher GSI score (p = 0.023 and 0.018, respectively). Again, PTSD patients showed higher GSI levels than non-PTSD patients (p = 0.014).

CONCLUSIONS

Cytokine levels were associated with level of mental distress as measured by the GSI scores, but this relationship was not present among those using anti-inflammatory drugs. We found no association between cytokine levels and development of GSI score over time.

Cytokine-mediated cellular immune activation in electroconvulsive therapy: A CSF study in patients with treatment-resistant depression

Objectives: Evidence points towards an important relationship between the antidepressant effects of electroconvulsive therapy (ECT) and the modulation of the immune system. To further elucidate this interplay, we performed a study on the effects of the antidepressant treatment by ECT on 25 cytokines in patients with depression.Methods: We measured 25 different cytokines (interleukin (IL)-1β, IL-1RA, Il-2, IL-2R, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 (p40/p70), IL-13, IL-15, IL-17, tumor necrosis factor-α, interferon (IFN)-α, IFN-γ, granulocyte-macrophage colony-stimulating factor, macrophage inflammatory protein (MIP)-1α, MIP-1β, IFN-γ-induced protein 10 (IP-10), monokine induced by IFN-γ, Eotaxin, Rantes and monocyte chemoattractant protein 1) in the cerebrospinal fluid (CSF) and blood of 12 patients with a severe and treatment-resistant depressive episode before and after a course of ECT.Results: CSF levels of IP-10, IL-5 and IL-8 were elevated after ECT and more ECT sessions were associated with the differences of CSF levels before and after ECT of IFN-γ, IL-2RA, Rantes, IL-6 and IL-1β. Responders and/or remitters had a decrease of CSF levels of IL-17, MIP-1α, Rantes and IL-2R during ECT. CSF IP-10 levels increased less during ECT in patients who had a remission.Conclusions: Although the sample size was small, we found different effects of the ECT treatment per se and of the antidepressant action induced by ECT in CSF and blood.

SOD2 genetic polymorphism (rs4880) has no impact on 6-month response to antidepressant treatment and inflammatory biomarkers in depressed patients

Two thirds of patients suffering from a major depressive episode (MDE) do not reach a complete response with antidepressant drugs. This lack of response is due to several factors, including genetic determinants. Since major depressive disorder is associated with inflammatory and oxidative stress abnormalities, the metabolism of superoxide anions might be involved in non-response to antidepressant drugs. Superoxide anions are metabolized by manganese-dependent superoxide dismutase (SOD2) in the mitochondria. A functional genetic polymorphism (SOD2, rs4880), responsible of a 40% reduction in enzyme activity, is associated with anti-inflammatory response of rosuvastatin. We investigated the association of ala-allele of SOD2 rs4880 and both antidepressant efficacy and inflammatory parameters in patients treated for a MDE with antidepressant drugs. The Hamilton Depression Rating Scale (HDRS) score and levels of plasma CRP and inflammatory cytokines were assessed at baseline, one month (M1), 3 months (M3) and 6 months (M6) after antidepressant treatment. They were compared according to SOD2 genetic polymorphism. Of the 484 patients studied, 361 (74.6%) carried the ala-allele (Ala group), 123 (25.4%) of them had Val/Val genotype (Val/Val group). No significant difference was observed between the Ala and Val/Val groups neither for baseline clinical characteristics, nor for HDRS scores, response/remission rates, plasma CRP and cytokine levels throughout the study. The rs4880 SOD2 genetic polymorphism was not associated with the clinical response and cytokines levels after antidepressant treatment. These data suggest that SOD2 is not a major genetic determinant of antidepressant response. Other genes of the oxidative stress pathways should be explored in further studies.

Variation in chemokines plasma concentrations in primary care depressed patients associated with Internet-based cognitive-behavioral therapy

How the presence of inflammation has repercussions for brain function is a topic of active research into depression. Signals released from immune system-related cells, including chemokines, might be indicative of active depression and can, hypothetically, serve as biomarkers of response to interventions, both pharmacological and psychological. The objective of this study is to analyze the peripheral plasma concentrations of CXCL12, CCL11, CX3CL1 and CCL2 in a cohort of depressed primary-care patients, as well as their evolution after an internet-based cognitive-behavioral intervention. The concentrations of those chemokines were measured in 66 primary-care patients with mild and moderate depression, before and after the intervention, as well as 60 controls, using multiplex immunoassays. Concentrations of CXCL12 and CCL2 were significantly higher in the clinical sample in comparison with controls. A stable multivariate discriminative model between both groups was found. Concentrations of all chemokines decreased after the internet-based psychological intervention. These findings support the implication of chemokines in depression, even in a sample of patients with mild and moderate severity. Furthermore, they demonstrate the need for further multidisciplinary research that confirms how biomarkers such as plasma chemokines can serve as a marker for depression and are sensitive to non-pharmacological interventions.

Multimodal Psychotherapeutic Inpatient Therapy of Depression Is Successful in Patients With High Cytokine Production

Objective: In experimental settings, systemically elevated inflammation markers interfere with major depression treatment. In German healthcare, compulsory national health insurance covers treatment of a wide variety of depressive disorders, if it follows evidence-based medicine guidelines combining recommended therapies. To date, little is known about the relevance of immune system cytokine production with regard to real-world clinical care for patients with moderate depression. Methods: Seventy three patients with moderate depression subjected to multimodal psychotherapeutic inpatient therapy (mPT) following a psychodynamic concept at a German university hospital were included. As a primary outcome, mPT success, evidenced by delta HADS "depression," was analyzed according to tumor necrosis factor alpha (TNFα) production by peripheral blood mononuclear cells (PBMC) after phytohemagglutinin (PHA) challenge at baseline. Secondary outcomes addressed the inflammatory response and mental health comparing high and low TNFα-producers. Results: First, higher PBMC TNFα production at baseline predicted a better mPT-outcome (R ² 0.162, p = 0.014). Second, patients with high TNFα (hTNF) at baseline produced significantly more acute inflammatory cytokines [interleukin (IL)1β, IL6), TH1/TH2 cytokines [interferon gamma (IFNγ), IL4] as well as eotaxin and IL2 compared to low TNFα producers (lTNF) (Cohen's ds between -0.532 and -1.013). Demographic data, diagnosis subtype-distribution, medication, systemic inflammation markers [C-reactive protein (CRP), high mobility group box 1 (HMGB1), leptin], anxiety and depression (HADS) did not differ. From baseline to mPT-discharge, HADS "depression" decreased in both hTNF (11.31 to 5.47, p = 0.001, d = 1.184) and lTNF patients (11.50-7.92, p = 0.001, d = -0.765), while PBMC cytokine production decreased significantly in hTNF (Cohen's ds between -0.304 and -0.345) with a significant group by time interaction for TH1/TH2 ratio. At the end of therapy, comparison of TNF groups revealed significantly lower depression-scores in hTNF compared to lTNF patients (5.47 compared to 7.92, p = 0.035, d = 0.504). Conclusions: Our study demonstrates successful treatment of depression in a clinical care setting using multimodal psychotherapy based on a psychodynamic concept following guideline recommendation. The greatest improvement in patient depression was linked to the highest production of TNFα by PBMCs at baseline. Our study contributes to the definition of patient subpopulations with differing cytokine responses that are related to succesful treatment of depression.

Association between cytokines and psychiatric symptoms in chronic fatigue syndrome and healthy controls

PURPOSE

The reports regarding the status of the immune system in patients with chronic fatigue syndrome/myalgic encephalopathy (CFS/ME) have been inconclusive. We approached this question by comparing a strictly defined group of CFS/ME outpatients to healthy control individuals, and thereafter studied cytokines in subgroups with various psychiatric symptoms.

MATERIALS AND METHODS

Twenty patients diagnosed with CFS/ME according to the Fukuda criteria and 20 age- and sex-matched healthy controls were enrolled in the study. Plasma was analysed by ELISA for levels of the cytokines TNF-α, IL-4, IL-6 and IL-10. Participants also answered questionnaires regarding health in general, and psychiatric symptoms in detail.

RESULTS

Increased plasma levels of TNF-α in CFS/ME patients almost reached significance compared to healthy controls (p = .056). When studying the CFS/ME and control groups separately, there was a significant correlation between TNF-α and The Hospital Anxiety and Depression Scale (HADS) depressive symptoms in controls only, not in the CFS/ME group. A correlation between IL-10 and psychoticism was found in both groups, whereas the correlation for somatisation was seen only in the CFS/ME group. When looking at the total population, there was a significant correlation between TNF-α and both the HADS depressive symptoms and the SCL-90-R cluster somatisation. Also, there was a significant association between IL-10 and the SCL-90-R cluster somatisation when analyzing the cohort (patients and controls together).

CONCLUSIONS

These findings indicate that immune activity in CFS/ME patients deviates from that of healthy controls, which implies potential pathogenic mechanisms and possible therapeutic approaches to CFS/ME. More comprehensive studies should be carried out on defined CFS/ME subgroups.

Head Transplantation: The Immune System, Phantom Sensations, and the Integrated Mind

The principal focus of this paper is to consider the implications of head and neck transplantation surgery on the issue of personal identity. To this end, it is noted that the immune system has not only been established to impose a level of self-identity on bodily cells, it has also been implicated in mental development and the regulation of mental state. In this it serves as a paradigm for the mind as the product of cephalic and extracephalic systems. The importance of bodily systems in identity is then discussed in relation to phantom tissue syndrome. The data strongly indicate that, even if surgically successful, head and neck transplantation will result in the loss of the continuity of personal identity.

Antidepressant efficacy of electroconvulsive therapy is associated with a reduction of the innate cellular immune activity in the cerebrospinal fluid in patients with depression

OBJECTIVES

A bidirectional link between the antidepressant effects of electroconvulsive therapy (ECT) and the modulation of the immune system has been proposed. To elucidate the interplay between antidepressant treatment and macrophage/microglia activation in humans, we performed a study on the effects of the antidepressant treatment by ECT on markers of macrophage/microglia activation in patients with depression.

METHODS

We measured six different markers (IL-6, neopterin, sCD14, sCD163 MIF and MCP1) of macrophage/microglia activation in the cerebrospinal fluid (CSF) and blood of 12 patients with a severe, treatment-resistant depressive episode before and after a course of ECT.

RESULTS

Some markers in the CSF of remitters were reduced after the ECT course and differed from non-remitters, but no differences were found before and after ECT independently from the antidepressant efficacy. CSF baseline levels of some markers could predict the reduction of depressive psychopathology during ECT. Higher CSF levels indicating increased macrophage/microglia activation at baseline predicted a better treatment response to ECT.

CONCLUSIONS

Although the sample size was small, our data suggest that macrophages/microglia are involved in the pathophysiology of major depression and that antidepressant efficacy by ECT might be partly explained by the modulation of the innate immune system within the brain.

The Food-Specific Serum IgG Reactivity in Major Depressive Disorder Patients, Irritable Bowel Syndrome Patients and Healthy Controls

There is an increasing amount of evidence which links the pathogenesis of irritable bowel syndrome (IBS) with food IgG hyperreactivity. Some authors have suggested that food IgG hyperreactivity could be also involved in the pathophysiology of major depressive disorder (MDD). The aim of this study was to compare levels of serum IgG against 39 selected food antigens between three groups of participants: patients with MDD (MDD group), patients with IBS (IBS group) and healthy controls (HC group). The study included 65 participants (22 in the MDD group, 22 in the IBS group and 21 in the HC group). Serum IgG levels were examined using enzyme-linked immunosorbent assay (ELISA). Medical records, clinical data and laboratory results were collected for the analysis. IgG food hyperreactivity (interpreted as an average of levels of IgG antibodies above 7.5 µg/mL) was detected in 28 (43%) participants, including 14 (64%) from the MDD group, ten (46%) from the IBS group and four (19%) from the HC group. We found differences between extreme IgG levels in MDD versus HC groups and in IBS versus HC groups. Patients with MDD had significantly higher serum levels of total IgG antibodies and IgG against celery, garlic and gluten compared with healthy controls. The MDD group also had higher serum IgG levels against gluten compared with the IBS group. Our results suggest dissimilarity in immune responses against food proteins between the examined groups, with the highest immunoreactivity in the MDD group. Further studies are needed to repeat and confirm these results in bigger cohorts and also examine clinical utility of IgG-based elimination diet in patients with MDD and IBS.

Effect of antidepressant treatment on peripheral inflammation markers - A meta-analysis

INTRODUCTION

Major Depressive Disorder (MDD) in accordance to the inflammatory concept is associated with complex immunological disturbances in the central nervous system (CNS). This is reflected by elevated plasma levels of inflammatory cytokines in depressed subjects. Although numerous studies report significant influence of antidepressants on pro-inflammatory/anti-inflammatory cytokines balance, the available data is often inconsistent regarding specific cytokines and drugs used. We aimed to perform a comprehensive meta-analysis of the effect of antidepressant treatment on a wide array of cytokines.

METHODS

We performed a systematic search of 6 databases, which yielded 32 studies measuring the levels of selected cytokines before and at a second time-point during antidepressant treatment. For meta-analysis of selected studies with a continuous measure we analysed variables containing the number of cases, mean and standard deviation of the level of IL-1ß, IL-2, IL-5, IL-6, IL-8, IL-10, CRP, TNF-α, IFN-γ levels observed in the different studies, in the intervention groups before and after antidepressant treatment.

RESULTS

Statistical analysis revealed significant decreases of IL-4, IL-6, and IL-10 in MDD subjects after antidepressant treatment. In case of IL-1ß the decrease was significant exclusively for SSRI drugs. We did not find any significant effect of antidepressant medication on IL-2, TNF-α IFN-γ and CRP.

CONCLUSIONS

Antidepressant treatment affects the levels of cytokines in depression. The immunological imbalance in MDD is complex and seems to be mediated by other factors yet to be elucidated. The credibility of our results is limited by high heterogeneity among studies and very few studies with a placebo-controlled design. Research with MDD subtypes, response to treatment status and cytokine associations with the kynurenine pathway taken into account pose a promising target for future studies.

PTSD patients show increasing cytokine levels during treatment despite reduced psychological distress

BACKGROUND

A reciprocal relationship between activated innate immune system and changes in mood and behavior has been established. There is still a paucity of knowledge on how the immune system responds during psychiatric treatment. We aimed to explore circulating cytokines and assess psychiatric symptom severity scores during 12 weeks of inpatient psychiatric treatment.

METHODS

The study was a longitudinal assessment of 124 patients (88 women and 36 men) in treatment at Modum Psychiatric Center, Norway. The patient sample comprised a mixed psychiatric population of whom 39 were diagnosed with posttraumatic stress disorder (PTSD). Serum blood samples for cytokine analysis and measures of mental distress using Global Severity Index were collected at admission (T₀), halfway (T₁), and before discharge (T₂). Other factors assessed were age, gender, and the use of antidepressants and anti-inflammatory drugs. Multilevel modeling was used for longitudinal analyses to assess the repeated cytokine samples within each patient.

RESULTS

Overall level of IL-1RA was higher in PTSD patients when compared to those without PTSD (P=0.021). The level of IL-1β, MCP-1, and TNF-α increased over time in PTSD compared to non-PTSD patients (P=0.025, P=0.011 and P=0.008, respectively). All patients experienced reduced mental distress as measured by self-reported Global Severity Index scores. Stratified analysis showed that PTSD patients who used anti-inflammatory drugs had higher levels of IL-1β (P=0.007) and TNF-α (P=0.049) than PTSD patients who did not use such drugs.

CONCLUSION

The study indicates that traumatized patients may have a distinct neuroimmune development during recovery. Their activated immune system shows even further activation during their rehabilitation despite symptom reduction.

The connections among suicidal behavior, lipid profile and low-grade inflammation in patients with major depressive disorder: a specific relationship with the neutrophil-to-lymphocyte ratio

OBJECTIVES

The role of inflammation and lipid metabolism in the pathophysiology of suicidal behavior has received particular attention in recent years. The neutrophil-to-lymphocyte ratio (NLR) has been suggested as a new and more reliable indicator of low-grade inflammation. NLR has been found to be altered in major depressive disorder (MDD) and has been related to various factors, including chronic stress and impulsivity that were previously reported to be related to suicidal behavior. We aimed to explore the roles of NLR, C-reactive protein (CRP) and serum lipid levels on suicidal behavior in patients with MDD.

METHODS

The study group consisted of 139 inpatients diagnosed with MDD [37 suicide attempters (SA); 102 suicide non-attempters (NSA)], 50 healthy controls and matched according to age, gender and education. NLR, PLR, CRP and lipid values were obtained from digital inpatient records.

RESULTS

CRP levels and NLR were substantially higher in patients with SA than in subjects with NSA and healthy comparison subjects after adjusting the confounding factors. The logistic regression included two predictive variables for suicide status in patients with depressive disorder (A) previous suicidal history; (B) NLR.

CONCLUSIONS

This is the first study suggesting that NLR may be a trait marker for suicidal vulnerability via a relationship between NLR and a recent suicide attempt in depressed inpatients. Future prospective studies are needed to determine the exact roles of NLR, and other inflammatory markers on suicidality in MDD.

Modulating Neuroinflammation to Treat Neuropsychiatric Disorders

Neuroinflammation is recognised as one of the potential mechanisms mediating the onset of a broad range of psychiatric disorders and may contribute to nonresponsiveness to current therapies. Both preclinical and clinical studies have indicated that aberrant inflammatory responses can result in altered behavioral responses and cognitive deficits. In this review, we discuss the role of inflammation in the pathogenesis of neuropsychiatric disorders and ask the question if certain genetic copy-number variants (CNVs) associated with psychiatric disorders might play a role in modulating inflammation. Furthermore, we detail some of the potential treatment strategies for psychiatric disorders that may operate by altering inflammatory responses.

Persistent increase in TNF and IL-1 markers in severe mental disorders suggests trait-related inflammation: a one year follow-up study

OBJECTIVE

We evaluated if plasma levels of inflammatory markers are persistently altered in severe mental disorders with psychotic symptoms or associated with state characteristics in a longitudinal study.

METHODS

Soluble tumor necrosis factor receptor 1 (sTNF-R1), interleukin-1 receptor antagonist (IL-1Ra), von Willebrand factor (VWF), and osteoprotegerin (OPG) were measured in schizophrenia (n = 69) and affective (n = 55) spectrum patients at baseline and at one-year follow-up, and compared to healthy controls (HC) (n = 92) with analysis of covariance. Association between change in symptoms and inflammatory markers was analyzed with mixed-effects models.

RESULTS

sTNF-R1 was higher in the schizophrenia (P < 0.0001) and affective disorders (P = 0.02) compared to HC, while IL-1Ra was higher in schizophrenia (P = 0.01) compared to HC at one year follow-up. There were no significant differences between schizophrenia and affective groups; however, levels in the affective group were in between schizophrenia and HC for sTNF-R1 and IL-1Ra. There were no significant associations between change in symptoms and inflammatory markers.

CONCLUSION

Persistently increased sTNF-R1 and IL-1Ra after one year in patients with severe mental disorders primarily reflecting data from the schizophrenia group may suggest that inflammation is a trait phenomenon, and not only the result of stress-related mechanisms associated with acute episodes.

Peripheral immune factors are elevated in women with current or recent alcohol dependence and associated with altered mood and memory

BACKGROUND

The adverse effects of alcohol on brain function result, in part, from inflammatory processes. The sex-specific neuropsychiatric consequences and inflammatory status of active alcohol dependence and early remission from dependence have not been investigated.

METHODS

Neuropsychiatric symptoms, inflammatory factors, and liver enzymes were compared in a prospective cohort study of adults with (n=51) or without (n=31) a current or recent history of alcohol dependence.

RESULTS

Neuropsychiatric profiles were similar in adults with current or recent alcohol dependence regardless of sex. In male and female participants measures of depression (female p<0.05, male p<0.001), anxiety (female p<0.001, male p<0.001), and memory complaints (female p<0.001, male p<0.05) were elevated, relative to non-dependent controls. Significant sex×alcohol dependence history interactions were observed for plasma levels of tissue inhibitor of metalloproteinase 1 (TIMP-1) and brain derived neurotrophic factor (BDNF), with women in the alcohol dependent group exhibiting increased levels of both analytes (p<0.05) relative to controls. Positive correlations between TIMP-1 levels and measures of depression (r²=0.35, p<0.01), anxiety (r²=0.24, p<0.05) and memory complaints (r²=0.44, p<0.01) were found in female, but not male, participants.

CONCLUSIONS

Though neuropsychiatric profiles were similar for men and women with current or recent alcohol dependence, plasma factors associated with increases in depression, anxiety, and memory impairment differed and support the need to tailor treatments based on sex.

Cognitive behaviour therapy and inflammation: A systematic review of its relationship and the potential implications for the treatment of depression

OBJECTIVE

There is growing evidence confirming increased inflammation in a subset of adults with depression. The impact of this relationship has mostly been considered in biologically based interventions; however, it also has potential implications for psychological therapies. Cognitive behaviour therapy is the most commonly used psychological intervention for the treatment of depression with theories around its efficacy primarily based on psychological mechanisms. However, cognitive behaviour therapy may have an effect on, and its efficacy influenced by, physiological processes associated with depression. Accordingly, the purpose of this systematic review was to examine the relationship between cognitive behaviour therapy and inflammation.

METHOD

Studies examining the anti-inflammatory effects of cognitive behaviour therapy in people with depression and other medical conditions (e.g. cancer, diabetes and heart disease) were examined. In addition, the relationship between change in inflammatory markers and change in depressive symptoms following cognitive behaviour therapy, and the influence of pre-treatment inflammation on cognitive behaviour therapy treatment response were reviewed.

RESULTS

A total of 23 studies investigating the anti-inflammatory effects of cognitive behaviour therapy were identified. In 14 of these studies, at least one reduction in an inflammatory marker was reported, increases were identified in three studies and no change was found in six studies. Three studies examined the relationship between change in inflammation and change in depressive symptoms following cognitive behaviour therapy. In two of these studies, change in depressive symptoms was associated with a change in at least one inflammatory marker. Finally, three studies examined the influence of pre-treatment inflammation on treatment outcome from cognitive behaviour therapy, and all indicated a poorer treatment response in people with higher premorbid inflammation.

CONCLUSION

Preliminary evidence suggests inflammation should be considered within the context of cognitive behaviour therapy, although robust studies examining the relationship are sparse, and heterogeneity between studies and populations examined was high. The potential treatment implications of the bi-directional relationship between inflammation and cognitive behaviour therapy are discussed, and recommendations for future research are proposed.

Changes in interleukin-6 levels during electroconvulsive therapy may reflect the therapeutic response in major depression

OBJECTIVE

Interleukin-6 (IL-6) has been reported to be elevated in major depressive disorder (MDD) but decreased by antidepressive medication. IL-6 levels are markedly elevated both after epileptic seizures and single electroconvulsive therapy (ECT) session, but long-term changes in IL-6 levels after ECT have not been studied. The correlation between immediate and long-term changes in proinflammatory cytokines and outcome after ECT was investigated.

METHOD

Thirty patients suffering from MDD participated in the study. IL-6, interleukin-1β (IL-1β) and interleukin-1 receptor antagonist (IL-1RA) levels were examined at baseline and at 2 and 4 h after the first, fifth and the last ECT sessions. The response to ECT was measured with Montgomery-Åsberg Depression Rating Scale (MADRS).

RESULTS

ECT repeatedly caused an increase in IL-6 levels at the 4-h time point. However, the baseline IL-6 levels decreased among remitters, but not among non-remitters, towards the end of ECT. IL-1β levels were mostly below detectable level, and IL-1Ra levels did not change during and after ECT.

CONCLUSION

ECT has distinct acute and long-term effects on IL-6 levels. Interestingly, the long-term effect of ECT on IL-6 seems to correlate with outcome, providing further evidence of the mechanism of action of ECT and supporting the inflammation theory in MDD.

The role of macrophages in anti-inflammatory activity of antidepressant drugs

Depression is a common disease influencing patients' quality of life, whose etiology involves complex interactions of environmental, genetic and immunological factors. The latter factors include proinflammatory activation of monocytes and macrophages and increased serum levels of proinflammatory cytokines, altogether formulated as the "macrophage theory of depression". Our current review summarizes the impact of the most commonly used antidepressant drugs on the immune response with special emphasis on the role of macrophages in the clinically observed effects. The anti-inflammatory action of antidepressants mainly results from their direct interaction with immune cells and from changes in the concentration and the relations of neurotransmitters sensed by these cells. The summarized data revealed that Mφs are one of the leading cell populations involved in drug-mediated immune effects that can be observed both in subjects with depression as well as in individuals not suffering from depression. Thus, currently reviewed immunomodulatory effects of the experimental use of different antidepressant drugs suggest the possibility of utilizing them in complex therapeutic strategies dedicated to various inflammatory and immune-mediated diseases. It is worth noting that an excessive inflammatory reaction is also associated with the pathogenesis of various cardiovascular, metabolic and neuro-endocrine diseases. Thus, the inclusion of antidepressants in the complex therapy of these disorders may have beneficial effects through the enhancement of the mood of the patient and alleviation of chronic inflammation. On the other hand, presented data suggest that the influence of chronically used antidepressants on anti-microbial and anti-tumor immunity could also be taken into consideration.

Oxidative stress: a potential link between emotional wellbeing and immune response

Emotional wellbeing is central to normal health and good living. Persistent psychological stress often disrupts emotional wellbeing and triggers onset of neuropsychiatric ailments. An integrated, multisystemic stress response involving neuroinflammatory, neuroendocrine and metabolic cascades seem to have some causative links. Of particular interest are the neuroinflammatory processes. Psychological stress has been suggested to negatively affect normal functioning of the immune system contributing to the pathophysiology of some neuropsychiatric conditions. Thus examination of the interaction between the immune system and the central nervous system is likely to reveal molecular targets critical for development of potential therapeutic and preventive measures. This review is a summarized discussion of evidence linking impact of psychological stress on the immune system, with a particular emphasis on oxidative stress mechanisms by which mental stress potentially impacts immune function leading to activation of multiple cascades resulting in subsequent manifestation of psychiatric symptomologies.

Stress-Induced Microglia Activation and Monocyte Trafficking to the Brain Underlie the Development of Anxiety and Depression

Psychosocial stress is capable of causing immune dysregulation and increased neuroinflammatory signaling by repeated activation of the neuroendocrine and autonomic systems that may contribute to the development of anxiety and depression. The stress model of repeated social defeat (RSD) recapitulates many of the stress-driven alterations in the neuroimmune system seen in humans experiencing repeated forms of stress and associated affective disorders. For example, RSD-induced neuronal and microglia activation corresponds with sympathetic outflow to the peripheral immune system and increased ability of bone marrow derived myeloid progenitor cells (MPC) to redistribute throughout the body, including to the central nervous system (CNS), reinforcing stress-associated behaviors. An overview of the neuroendocrine, immunological, and behavioral stress-induced responses will be reviewed in this chapter using RSD to illustrate the mechanisms leading to stress-related alterations in inflammation in both the periphery and CNS, and stress-related changes in behavioral responses.