Childhood inflammatory markers and risks for psychosis and depression at age 24: Examination of temporality and specificity of association in a population-based prospective birth cohort

Depressive and Negative Symptoms in the Early and Established Stages of Schizophrenia: Integrating Structural Brain Alterations, Cognitive Performance, and Plasma Interleukin 6 Levels

Background

Depressive and negative symptoms are related to poor functional outcomes in schizophrenia. Cognitive deficits, reduced brain cortical thickness and volumes, and inflammation may contribute to depressive and negative symptoms, but pharmacological treatment and disease progression may confound the associations.

Methods

We evaluated whether higher plasma interleukin 6 (IL-6) levels would be associated with more severe negative or depressive symptoms in schizophrenia and explored illness stage utilizing early (BeneMin [Benefit of Minocycline on Negative Symptoms of Psychosis: Extent and Mechanism], n = 201, 72.8% male) and established (iRELATE [Immune Response & Social Cognition in Schizophrenia], n = 94, 67.3% male) schizophrenia cohorts. Using structural equation modeling in a subsample (iRELATE: n = 42, 69.0% male; BeneMin: n = 102, 76.5% male) with data on structural brain metrics (cortical thickness and volume), general cognitive performance, and plasma IL-6 levels, we assessed the interrelationships between these variables on depressive and negative symptom severity in early and established schizophrenia samples combined and in early schizophrenia only. All analyses were adjusted for sex, age, and chlorpromazine equivalent dose.

Results

Higher plasma IL-6 levels were related to more severe depressive symptoms in early schizophrenia (p < .05) and negative symptoms in established schizophrenia (p < .05). Structural equation modeling findings in early and established schizophrenia samples combined and early schizophrenia only showed that the interrelationship between higher plasma IL-6 levels, structural brain metrics, and general cognitive performance did not predict the severity of depressive and negative symptoms (p > .05). Higher plasma IL-6 levels and lower general cognitive performance were associated with reduced brain metrics (p < .05).

Conclusions

Our results indicate that higher plasma IL-6 levels may be differently associated with the severity of depressive and negative symptoms dependent on the illness stage. Future work identifying elevated levels of inflammation in larger samples may allow stratification and personalized intervention by subgroups who are at risk of poor outcomes.

Childhood allergy and anxiety/depression in early adulthood: A longitudinal study in the ALSPAC birth cohort

BACKGROUND

Allergic disease and common mental disorders frequently co-occur. However, little is known about the longitudinal impact of childhood allergy on the subsequent risk of developing anxiety or depression, and the possible biological mechanisms for this.

METHODS

We performed longitudinal analyses of data from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort. The baseline sample comprised n = 5256 children with allergy data available at age 7yrs. We used multivariable regression to test associations between childhood allergy at age 7yrs and: a) four inflammatory markers at age 9yrs; b) depression and anxiety measures between ages 10-24yrs. Allergy measures included biological markers (total serum immunoglobulin E (tIgE), number of positive skin prick tests (SPTs)), and presence of eczema, asthma and/or food allergy (mother reported). Inflammatory markers were interleukin-6 (IL-6), C-reactive protein (CRP), IL-4 and IL-13. We used structural equation modelling to test whether inflammatory markers mediated the association between tIgE and depression/anxiety.

RESULTS

tIgE and having ≥ 1 positive SPT at age 7 were associated with IL-6 levels at age 9 (adjusted β = 0.09; 95 % CI 0.06-0.13; p < 0.001 and adjusted β = 0.06; 95 % CI 0.03-0.09; p < 0.001 respectively), but not with CRP, IL-4 or IL13 levels. We found no strong evidence of an association between childhood allergy and subsequent depression/anxiety during adolescence and early adulthood. This finding was consistent across biological and mother-reported allergy measures.

CONCLUSIONS

Biological markers of childhood allergy are associated with IL-6, a key inflammatory cytokine. However, childhood allergy may not have a large long-term effect on subsequent depression/anxiety.

Linking childhood allostatic load, early adversity and the emergence of mental health symptoms in early adulthood: Analysis of the ALSPAC longitudinal birth cohort

BACKGROUND

It has been well-established that the allostatic load (AL) index, a cumulative score of multi-system dysregulation in response to chronic stress, is significantly increased at the time of a psychiatric diagnosis. However, no studies have investigated if there is an association between the AL index in childhood and the later development of mental health symptoms in young adults.

METHODS

Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), a population cohort from Bristol, United Kingdom, we investigated the AL index at age 9 years and the risks for mental health symptoms at age 24 years. We used multinomial logistic regression analysis to investigate the association between AL threshold (categorised into bottom third: AL index ≤ 7, middle third: AL index = 7.1-9.9, and top third: AL index ≥ 10) and mental health symptoms while adjusting for sex, the age of mother at delivery, and social class. We used a relative risk ratio (RRR) and 95 % confidence interval(CI) for each variable. We further investigated the association between adverse childhood experiences (ACEs) and mental health symptoms.

RESULTS

We identified a significant association between sex and mental health symptoms, with more females (59 % vs 41 %) showing mental health symptoms than males. We found no direct association between the AL index at age 9 and the later development of mental health symptoms. However, an RRR analysis showed that individuals in the middle and the top third of the AL index had an RRR of 1.99 and 2.20, respectively, to develop mental health symptoms if they were females. We found that individuals who experienced ACE had a much higher risk of developing mental health symptoms as young adults, with the adjusted RRR of 5.39 (95 % CI: 3.00;9.67), 6.79 (95 % CI: 2.55; 18.1), and 2.10 (95 % CI: 0.37;11.8) for neglect, physical and sexual abuse, respectively, in individuals with mood disorder symptoms. The adjusted RRR for neglect and physical and sexual abuse in individuals with psychotic symptoms was 0.99 (95 % CI: 0.37; 2.59), 2.92 (95 % CI: 0.35; 24.4), and 10.5 (95 % CI: 0.99; 112), respectively.

CONCLUSION

Although the AL index in childhood was not directly associated with the later development of psychotic and mood disorder symptoms in this cohort, females in the higher tertiles of the AL index measured at 9 years of age had an elevated risk of mental health symptoms as young adults. In line with previous work, a strong association was identified between childhood adversity and mental health symptoms in young adulthood. These results highlight the importance of considering the impact of early stress on biological embedding and the later emergence of mental health problems, especially in females.

Associations between IL-6 and trajectories of depressive symptoms across the life course: Evidence from ALSPAC and UK Biobank cohorts

BACKGROUND

Peripheral inflammatory markers, including serum interleukin 6 (IL-6), are associated with depression, but less is known about how these markers associate with depression at different stages of the life course.

METHODS

We examined the associations between serum IL-6 levels at baseline and subsequent depression symptom trajectories in two longitudinal cohorts: ALSPAC (age 10-28 years; N = 4,835) and UK Biobank (39-86 years; N = 39,613) using multilevel growth curve modeling. Models were adjusted for sex, BMI, and socioeconomic factors. Depressive symptoms were measured using the Short Moods and Feelings Questionnaire in ALSPAC (max time points = 11) and the Patient Health Questionnaire-2 in UK Biobank (max time points = 8).

RESULTS

Higher baseline IL-6 was associated with worse depression symptom trajectories in both cohorts (largest effect size: 0.046 [ALSPAC, age 16 years]). These associations were stronger in the younger ALSPAC cohort, where additionally higher IL-6 levels at age 9 years was associated with worse depression symptoms trajectories in females compared to males. Weaker sex differences were observed in the older cohort, UK Biobank. However, statistically significant associations (pFDR <0.05) were of smaller effect sizes, typical of large cohort studies.

CONCLUSIONS

These findings suggest that systemic inflammation may influence the severity and course of depressive symptoms across the life course, which is apparent regardless of age and differences in measures and number of time points between these large, population-based cohorts.

White blood cell counts, ratios, and C-reactive protein among individuals with schizophrenia spectrum disorder and associations with long-term outcomes: a population-based study

BACKGROUND

Immune mechanisms are associated with adverse outcomes in schizophrenia; however, the predictive value of various peripheral immune biomarkers has not been collectively investigated in a large cohort before.

OBJECTIVE

To investigate how white blood cell (WBC) counts, ratios, and C-Reactive Protein (CRP) levels influence the long-term outcomes of individuals with schizophrenia spectrum disorder (SSD).

METHODS

We identified all adults in the Central Denmark Region during 1994-2013 with a measurement of WBC counts and/or CRP at first diagnosis of SSD. WBC ratios were calculated, and both WBC counts and ratios were quartile-categorized (Q4 upper quartile). We followed these individuals from first diagnosis until outcome of interest (death, treatment resistance and psychiatric readmissions), emigration or December 31, 2016, using Cox regression analysis to estimate adjusted hazard ratios (aHRs).

RESULTS

Among 6,845 participants, 375 (5.5 %) died, 477 (6.9 %) exhibited treatment resistance, and 1470 (21.5 %) were readmitted during follow-up. Elevated baseline levels of leukocytes, neutrophils, monocytes, LLR, NLR, MLR, and CRP increased the risk of death, whereas higher levels of lymphocytes, platelets, and PLR were associated with lower risk. ROC analysis identified CRP as the strongest predictor for mortality (AUC=0.84). Moreover, elevated levels of leukocytes, neutrophils, monocytes, LLR, NLR and MLR were associated with treatment resistance. Lastly, higher platelet counts decreased the risk of psychiatric readmissions, while elevated LLR increased this risk.

CONCLUSIONS

Elevated levels of WBC counts, ratios, and CRP at the initial diagnosis of SSD are associated with mortality, with CRP demonstrating the highest predictive value. Additionally, certain WBC counts and ratios are associated with treatment resistance and psychiatric readmissions.

Trajectories of Inflammation in Youth and Risk of Mental and Cardiometabolic Disorders in Adulthood

Importance

Research suggests that low-grade, nonresolving inflammation may predate adult mental and physical illness. However, evidence to date is largely cross-sectional or focuses on single disorder outcomes.

Objectives

To examine trajectories of inflammation as measured by C-reactive protein (CRP) levels in a large sample of children and adolescents, and to explore associations between different identified trajectories and mental and related cardiometabolic health outcomes in early adulthood.

Design, Setting, and Participants

In a longitudinal cohort study using data from the large UK-based Avon Longitudinal Study of Parents and Children (ALSPAC), latent class growth analysis (LCGA) was used to explore different trajectories of inflammation, with logistic regression exploring association with mental and physical health outcomes. Participants with measurable CRP data and associated mental and cardiometabolic health outcomes recorded were included in the analysis. Data analysis was performed from May 1, 2023, to March 30, 2024.

Exposures

Inflammation was assessed via CRP levels at ages 9, 15, and 17 years. LCGA was used to identify different trajectories of inflammation.

Main Outcomes and Measures

Outcomes assessed at age 24 years included psychotic disorders, depressive disorders, anxiety disorders, hypomania, and, as a measure of insulin resistance, Homeostasis Model Assessment (HOMA2) score.

Results

A total of 6556 participants (3303 [50.4%] female) were included. Three classes of inflammation were identified: persistently low CRP levels (reference class, n = 6109); persistently raised CRP levels, peaking at age 9 years (early peak, n = 197); and persistently raised CRP levels, peaking at age 17 years (late peak, n = 250). Participants in the early peak group were associated with a higher risk of psychotic disorder (odds ratio [OR], 4.60; 95% CI, 1.81-11.70; P = .008), a higher risk of severe depression (OR, 4.37; 95% CI, 1.64-11.63; P = .02), and higher HOMA2 scores (β = 0.05; 95% CI, 0.01-0.62, P = .04) compared with participants with persistently low CRP. The late peak group was not associated with any outcomes at age 24 years.

Conclusions and Relevance

Low-grade systemic inflammation peaking in midchildhood was associated with specific mental and cardiometabolic disorders in young adulthood. These findings suggest that low-grade persistent inflammation in early life may be an important shared common factor for mental-physical comorbidity and so could be relevant to future efforts of patient stratification and risk profiling.

Correlating plasma protein profiles with symptomatology and treatment response in acute phase and early remission of major depressive disorder

Objectives

This study aimed to explore the relationship between plasma proteome and the clinical features of Major Depressive Disorder (MDD) during treatment of acute episode.

Methods

In this longitudinal observational study, 26 patients hospitalized for moderate to severe MDD were analyzed. The study utilized Liquid Chromatography with Tandem Mass Spectrometry (LC-MS/MS) alongside clinical metrics, including symptomatology derived from the Montgomery-Åsberg Depression Rating Scale (MADRS). Plasma protein analysis was conducted at the onset of acute depression and 6 weeks into treatment. Analytical methods comprised of Linear Models for Microarray Data (LIMMA), Weighted Correlation Network Analysis (WGCNA), Generalized Linear Models, Random Forests, and The Database for Annotation, Visualization and Integrated Discovery (DAVID).

Results

Five distinct plasma protein modules were identified, correlating with specific biological processes, and uniquely associated with symptom presentation, the disorder's trajectory, and treatment response. A module rich in proteins related to adaptive immunity was correlated with the manifestation of somatic syndrome, treatment response, and inversely associated with achieving remission. A module associated with cell adhesion was linked to affective symptoms and avolition, and played a role in the initial episodes and treatment response. Another module, characterized by proteins involved in blood coagulation and lipid transport, exhibited negative correlations with a variety of MDD symptoms and was predominantly associated with the manifestation of psychotic symptoms.

Conclusion

This research points to a complex interplay between the plasma proteome and MDD's clinical presentation, suggesting that somatic, affective, and psychotic symptoms may represent distinct endophenotypic manifestations of MDD. These insights hold potential for advancing targeted therapeutic strategies and diagnostic tools.

Limitations

The study's limited sample size and its naturalistic design, encompassing diverse treatment modalities, present methodological constraints. Furthermore, the analysis focused on peripheral blood proteins, with potential implications for interpretability.

Role of Inflammation in Short Sleep Duration Across Childhood and Psychosis in Young Adulthood

Importance

Short sleep duration over a prolonged period in childhood could have a detrimental impact on long-term mental health, including the development of psychosis. Further, potential underlying mechanisms of these associations remain unknown.

Objective

To examine the association between persistent shorter nighttime sleep duration throughout childhood with psychotic experiences (PEs) and/or psychotic disorder (PD) at age 24 years and whether inflammatory markers (C-reactive protein [CRP] and interleukin 6 [IL-6]) potentially mediate any association.

Design, Setting, and Participants

This cohort study used data from the Avon Longitudinal Study of Parents and Children. Data analysis was conducted from January 30 to August 1, 2023.

Exposures

Nighttime sleep duration was collected at 6, 18, and 30 months and at 3.5, 4 to 5, 5 to 6, and 6 to 7 years.

Main Outcomes and Measures

PEs and PD were assessed at age 24 years from the Psychosislike Symptoms Interview. CRP level at ages 9 and 15 years and IL-6 level at 9 years were used as mediators. Latent class growth analyses (LCGAs) were applied to detect trajectories of nighttime sleep duration, and logistic regressions were applied for the longitudinal associations between trajectories of nighttime sleep duration and psychotic outcomes at 24 years. Path analyses were applied to test CRP and IL-6 as potential mediators.

Results

Data were available on 12 394 children (6254 female [50.5%]) for the LCGA and on 3962 young adults (2429 female [61.3%]) for the logistic regression and path analyses. The LCGA identified a group of individuals with persistent shorter nighttime sleep duration across childhood. These individuals were more likely to develop PD (odds ratio [OR], 2.50; 95% CI, 1.51-4.15; P < .001) and PEs (OR, 3.64; 95% CI, 2.23-5.95; P < .001) at age 24 years. Increased levels of IL-6 at 9 years, but not CRP at 9 or 15 years, partially mediated the associations between persistent shorter sleep duration and PD (bias-corrected estimate = 0.003; 95% CI, 0.002-0.005; P = .007) and PEs (bias-corrected estimate = 0.002; 95% CI, 0-0.003; P = .03) in young adulthood.

Conclusions and Relevance

Findings of this cohort study highlight the necessity of addressing short sleep duration in children, as persistence of this sleep problem was associated with subsequent psychosis. This study also provides preliminary evidence for future targeted interventions in children addressing both sleep and inflammatory responses.

Inflammatory markers, somatic complaints, use of medication and health care in 11-year-old children at familial high risk of schizophrenia or bipolar disorder compared with population-based controls. The Danish High Risk and Resilience Study - via 11

PURPOSE

Patients with schizophrenia or bipolar disorder are at increased risk of somatic illnesses and have more somatic complaints compared with the general population. Schizophrenia and bipolar disorder are highly heritable. Already during childhood, children at familial high risk of schizophrenia (FHR-SZ) or bipolar disorder (FHR-BD) are at increased risk of psychiatric disorders and cognitive and social impairments. Knowledge about physical conditions is sparse.

MATERIALS AND METHODS

Through blood tests (n = 293), interviews, and questionnaires, we assessed inflammatory markers, somatic complaints, medication - and health care use in 11-year-old children at FHR-SZ, FHR-BD, and population-based controls (PBC).

RESULTS

Children at FHR-SZ had higher concentrations of leucocytes (mean 6.41, SD 0.73) compared with PBC (mean 5.78, SD 0.27, p = 0.005) and of neutrophilocytes (FHR-SZ: mean 3.11, SD 1.32, PBC: mean 2.70, SD 0.96, p = 0.024). Compared with PBC (26.6%), more children at FHR-SZ (40.5%, p = 0.007) reported somatic complaints. So did caregivers and teachers to children at FHR-BD. Somatic complaints, higher concentrations of leucocytes, and neutrophilocytes were associated with lower levels of physical activity. Children at FHR-BD with psychiatric disorders reported more somatic complaints compared with those without.

CONCLUSION

Children at FHR-SZ had higher concentrations of leucocytes and neutrophilocytes than PBC. Children at FHR-SZ or FHR-BP displayed more somatic complaints than controls. Our study highlights rarely explored disadvantage of being born to parents with schizophrenia or bipolar disorder. To enhance understanding of how physical conditions in childhood may interplay with later transition to mental disorders in children at FHR-SZ and FHR-BD, further research is needed.

Plasma complement and coagulation proteins as prognostic factors of negative symptoms: An analysis of the NAPLS 2 and 3 studies

INTRODUCTION

Negative symptoms impact the quality of life of individuals with psychosis and current treatment options for negative symptoms have limited effectiveness. Previous studies have demonstrated that complement and coagulation pathway protein levels are related to later psychotic experiences, psychotic disorder, and functioning. However, the prognostic relationship between complement and coagulation proteins and negative symptoms is poorly characterised.

METHODS

In the North American Prodrome Longitudinal Studies 2 and 3, negative symptoms in 431 individuals at clinical high-risk for psychosis (mean age: 18.2, SD 3.6; 42.5 % female) were measured at multiple visits over 2 years using the Scale of Psychosis-Risk Symptoms. Plasma proteins were quantified at baseline using mass spectrometry. Four factors were derived to represent levels of proteins involved in the activation or regulation of the complement or coagulation systems. The relationships between standardised protein group factors and serial measurements of negative symptoms over time were modelled using generalised least squares regression. Analyses were adjusted for baseline candidate prognostic factors: negative symptoms, positive symptoms, functioning, depressive symptoms, suicidal ideation, cannabis use, tobacco use, antipsychotic use, antidepressant use, age, and sex.

RESULTS

Clinical and demographic prognostic factors of follow-up negative symptoms included negative, positive, and depressive symptoms, functioning, and age. Adjusting for all candidate prognostic factors, the complement regulators group and the coagulation regulators group were identified as prognostic factors of follow-up negative symptoms (β: 0.501, 95 % CI: 0.160, 0.842; β: 0.430, 95 % CI: 0.080, 0.780 respectively. The relationship between complement regulator levels and negative symptoms was also observed in NAPLS2 alone (β: 0.501, 95 % CI: -0.037, 1.039) and NAPLS3 alone, additionally adjusting for BMI (β: 0.442, 95 % CI: 0.127, 0.757).

CONCLUSION

The results indicate that plasma complement and coagulation regulator levels are prognostic factors of negative symptoms, independent of clinical and demographic prognostic factors. These results suggest complement and coagulation regulator levels could have potential utility in informing treatment decisions for negative symptoms in individuals at risk.

Schizophrenia polygenic risk scores, clinical variables and genetic pathways as predictors of phenotypic traits of bipolar I disorder

AIM

We investigated the predictive value of polygenic risk scores (PRS) derived from the schizophrenia GWAS (Trubetskoy et al., 2022) (SCZ3) for phenotypic traits of bipolar disorder type-I (BP-I) in 1878 BP-I cases and 2751 controls from Romania and UK.

METHODS

We used PRSice-v2.3.3 and PRS-CS for computing SCZ3-PRS for testing the predictive power of SCZ3-PRS alone and in combination with clinical variables for several BP-I subphenotypes and for pathway analysis. Non-linear predictive models were also used.

RESULTS

SCZ3-PRS significantly predicted psychosis, incongruent and congruent psychosis, general age-of-onset (AO) of BP-I, AO-depression, AO-Mania, rapid cycling in univariate regressions. A negative correlation between the number of depressive episodes and psychosis, mainly incongruent and an inverse relationship between increased SCZ3-SNP loading and BP-I-rapid cycling were observed. In random forest models comparing the predictive power of SCZ3-PRS alone and in combination with nine clinical variables, the best predictions were provided by combinations of SCZ3-PRS-CS and clinical variables closely followed by models containing only clinical variables. SCZ3-PRS performed worst. Twenty-two significant pathways underlying psychosis were identified.

LIMITATIONS

The combined RO-UK sample had a certain degree of heterogeneity of the BP-I severity: only the RO sample and partially the UK sample included hospitalized BP-I cases. The hospitalization is an indicator of illness severity. Not all UK subjects had complete subphenotype information.

CONCLUSION

Our study shows that the SCZ3-PRS have a modest clinical value for predicting phenotypic traits of BP-I. For clinical use their best performance is in combination with clinical variables.

Transdiagnostic dimensions of symptoms and experiences associated with immune proteins in the continuity of psychosis

BACKGROUND

There is limited evidence as to whether the immune protein profile is associated with a particular symptomatology pattern across the psychosis continuum.

METHODS

We estimated two bifactor models of general and specific dimensions of psychotic experiences in unaffected siblings of patients (n = 52) and community controls (n = 200), and of psychotic symptoms in first-episode psychosis (FEP) patients (n = 110). We evaluated associations between these transdiagnostic dimensions and trait (TNF-α, IFN-γ), state (IL-6, IL-1β), and regulatory (TGF-β, IL-10, IL-4) cytokines. We explored whether schizophrenia genetic liability (schizophrenia polygenic risk score; SZ-PRS) modified the associations.

RESULTS

High levels of trait marker IFN-γ were associated with the severity of general psychosis dimension in the unaffected siblings and community controls, expanding to the depressive dimension in siblings and to the manic dimension in FEP. High TNF-α levels were associated with more positive psychotic experiences in unaffected siblings and manic symptoms in FEP. Low levels of state markers IL-6 and IL-1β were observed in unaffected siblings presenting more depressive experiences. Still, high levels of IL-6 and IL-1β were associated with the severity of the depressive and negative symptom dimensions at FEP. The severity of transdiagnostic dimension scores across the three groups was associated with lower regulatory cytokines. Exploratory analysis suggested that a high SZ-PRS contributed mostly to associations with psychotic dimensions.

CONCLUSIONS

IFN-γ mapped onto the multidimensional expression of psychosis, reinforcing the trait concept. State markers IL-6 and IL-1β may fluctuate along the spectrum. Dysfunction in the regulatory arm may disinhibit the inflammatory system. Associations with psychotic dimensions may be more prone to SZ-PRS susceptibility.

Childhood maltreatment influences adult brain structure through its effects on immune, metabolic, and psychosocial factors

Childhood maltreatment (CM) leads to a lifelong susceptibility to mental ill-health which might be reflected by its effects on adult brain structure, perhaps indirectly mediated by its effects on adult metabolic, immune, and psychosocial systems. Indexing these systemic factors via body mass index (BMI), C-reactive protein (CRP), and rates of adult trauma (AT), respectively, we tested three hypotheses: (H1) CM has direct or indirect effects on adult trauma, BMI, and CRP; (H2) adult trauma, BMI, and CRP are all independently related to adult brain structure; and (H3) childhood maltreatment has indirect effects on adult brain structure mediated in parallel by BMI, CRP, and AT. Using path analysis and data from N = 116,887 participants in UK Biobank, we find that CM is related to greater BMI and AT levels, and that these two variables mediate CM's effects on CRP [H1]. Regression analyses on the UKB MRI subsample (N = 21,738) revealed that greater CRP and BMI were both independently related to a spatially convergent pattern of cortical effects (Spearman's ρ = 0.87) characterized by fronto-occipital increases and temporo-parietal reductions in thickness. Subcortically, BMI was associated with greater volume, AT with lower volume and CPR with effects in both directions [H2]. Finally, path models indicated that CM has indirect effects in a subset of brain regions mediated through its direct effects on BMI and AT and indirect effects on CRP [H3]. Results provide evidence that childhood maltreatment can influence brain structure decades after exposure by increasing individual risk toward adult trauma, obesity, and inflammation.

Associations between plasma inflammatory markers and psychotic disorder, depressive disorder and generalised anxiety disorder in early adulthood: A nested case-control study

BACKGROUND

Low-grade inflammation may occur in association with several mental disorders of early adulthood, though associations with markers of chronic inflammation such as soluble urokinase plasminogen activator receptor (suPAR) are less well-established. We aimed to examine associations between acute and chronic inflammatory markers and mental disorders, as well as psychiatric co-morbidity, in young adults aged 24 years in the Avon Longitudinal Study of Parents and Children.

METHODS

Included were 781 participants (of 4019 who attended at age 24 years) who completed psychiatric assessments and provided plasma samples. Of these, 377 met criteria for psychotic disorder, depressive disorder or generalised anxiety disorder and 404 did not. Plasma concentrations of IFN-γ, IL-6, IL-8, IL-10, TNF-α, CRP, sVCAM1, sICAM1, suPAR and alpha-2-macroglobulin were measured using immunoassays. Logistic regression compared standardised inflammatory marker levels in cases and controls. Negative binomial regression evaluated associations between inflammatory markers and co-morbidity (number of mental disorders). Models were adjusted for sex, body mass index, cigarette smoking, cannabis use and employment status, then additionally for childhood trauma.

RESULTS

For psychotic disorder, there was evidence for associations with IL-6 (odds ratio[OR] 1.68, 95 %CI 1.20-2.34) and suPAR (OR 1.74, 95 %CI 1.17-2.58). There was weaker evidence for an association between suPAR and depressive disorder (OR 1.31, 95 %CI 1.05-1.62). There was little evidence for associations between inflammatory markers and generalised anxiety disorder. There was weak evidence for an association between suPAR and co-morbidity (β 0.10, 95 %CI 0.01-0.19). There was little evidence for additional confounding by childhood trauma.

CONCLUSIONS

There was evidence that 24-year-olds with psychotic disorder had raised plasma IL-6 and suPAR concentrations compared to controls. These findings have implications regarding the role of inflammation in mental disorders in early adulthood.

The role of inflammation in the prospective associations between early childhood sleep problems and ADHD at 10 years: findings from a UK birth cohort study

BACKGROUND

Several underlying mechanisms potentially account for the link between sleep and attention deficit and hyperactivity disorder (ADHD), including inflammation. However, studies so far have been cross sectional. We investigate (a) the association between early childhood sleep and probable ADHD diagnosis in childhood and (b) whether childhood circulating inflammatory markers mediate these prospective associations.

METHODS

Data from the Avon Longitudinal Study of Parents and Children were available for 7,658 10-year-old children. Parent-reported sleep duration, night awakening frequency and regular sleep routines were collected at 3.5 years. The Development and Wellbeing Assessment was administered to capture children with clinically relevant ADHD symptoms, or probable ADHD diagnosis. Blood samples were collected at 9 years, from which two inflammatory markers were obtained [interleukin-6 (IL-6) and C-reactive protein (CRP)]. Logistic regression analyses were applied to investigate the associations between sleep variables at 3.5 years and probable ADHD diagnosis at 10 years. Further, path analysis was applied to examine the potential mediating role of inflammation at 9 years (as measured by CRP and IL-6) in the associations between early sleep and ADHD at 10 years.

RESULTS

Less regular sleep routines (OR = 0.51, 95% CI = 0.28-0.93, p = .029), shorter nighttime sleep (OR = 0.70, 95% CI = 0.56-0.89, p = .004) and higher night awakening frequency (OR = 1.27, 95% CI = 1.06-1.52, p = .009) at 3.5 years were associated with higher odds of ADHD at 10 years. Further, IL-6 at 9 years, but not CRP, mediated the association between irregular sleep routines and ADHD (bias-corrected estimate, -0.002; p = .005) and between night awakening and ADHD (bias-corrected estimate, 0.002; p = .003).

CONCLUSIONS

Several sleep problems in early childhood constitute a risk factor for probable ADHD diagnosis at 10 years. Further, these associations are partially mediated by IL-6 at 9 years. These results open a new research vista to the pathophysiology of ADHD and highlight sleep and inflammation as potential preventative targets for ADHD.

Association between subclinical hypothyroidism and psychotic features in Chinese young adults with first-episode and untreated major depressive disorder

BACKGROUND

Thyroid dysfunction is often reported in patients with major depressive disorder (MDD) and may be associated with depression severity and psychotic symptoms. We included young adults with first-episode and untreated MDD to avoid the effect of age and disease duration on thyroid dysfunction and psychotic symptoms.

METHODS

481 young patients with MDD (aged 18-24 years) were recruited. The Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale (HAMA), Positive and Negative Syndrome Scale (PANSS) positive subscale and Global Impression of Severity Scale (CGIS) were used to assess depression, anxiety, psychotic symptoms and disease severity, respectively.

RESULTS

The prevalence rate of subclinical hypothyroidism (SCH) and thyroid antibody positivity was 56.76 % (273/481) and 26.61 % (128/481) in young MDD, respectively. A higher proportion of MDD patients with SCH displayed psychotic features (14.3 % vs. 5.3 %, OR = 2.985, p = 0.001). TSH was a risk factor for psychotic symptoms in MDD patient with SCH (B = 0.136, p = 0.017, OR = 1.384), with an AUC of 0.709, indicating acceptable discrimination. Multivariate regression analysis also showed that TSH was also independently associated with PANSS positive score (B = 0.339, t = 2.019, p = 0.045).

LIMITATION

This cross-sectional study design did not demonstrate a causal relationship. Relying solely on the PANSS positive subscale as psychotic symptoms may cause bias.

CONCLUSIONS

Our findings suggest that SCH is common in young patients with first-episode and untreated MDD. MDD patients with higher TSH levels may suffer from more psychotic symptoms. Regular screening of serum thyroid hormones is necessary in patients with MDD.

Early-life inflammatory markers and subsequent psychotic and depressive episodes between 10 to 28 years of age

Inflammation is implicated in depression and psychosis, including association of childhood inflammatory markers on the subsequent risk of developing symptoms. However, it is unknown whether early-life inflammatory markers are associated with the number of depressive and psychotic symptoms from childhood to adulthood. Using the prospective Avon Longitudinal Study of Children and Parents birth cohort (N = up-to 6401), we have examined longitudinal associations of early-life inflammation [exposures: interleukin-6 (IL-6), C-reactive protein (CRP) levels at age 9y; IL-6 and CRP DNA-methylation (DNAm) scores at birth and age 7y; and IL-6 and CRP polygenic risk scores (PRSs)] with the number of depressive episodes and psychotic experiences (PEs) between ages 10-28 years. Psychiatric outcomes were assessed using the Short Mood and Feelings Questionnaire and Psychotic Like Symptoms Questionnaires, respectively. Exposure-outcome associations were tested using negative binomial models, which were adjusted for metabolic and sociodemographic factors. Serum IL-6 levels at age 9y were associated with the total number of depressive episodes between 10 and 28y in the base model (n = 4835; β = 0.066; 95%CI:0.020-0.113; pFDR = 0.041) which was weaker when adjusting for metabolic and sociodemographic factors. Weak associations were observed between inflammatory markers (serum IL-6 and CRP DNAm scores) and total number of PEs. Other inflammatory markers were not associated with depression or PEs. Early-life inflammatory markers are associated with the burden of depressive episodes and of PEs subsequently from childhood to adulthood. These findings support a potential role of early-life inflammation in the aetiology of depression and psychosis and highlight inflammation as a potential target for treatment and prevention.

Non-invasive diagnosis and monitoring tool of children’s mental health: A point-of-care immunosensor for IL-6 quantification in saliva samples

Mental disorders are commonly featured as chronic conditions with often onset during childhood. In this context, inflammation has been associated with a higher risk of developing physical and mental health problems. Interleukin (IL)-6 is a key mediator of inflammatory responses and plays a pivotal role in immune and nervous system interaction. High levels of IL-6 during childhood are associated with mental problems, indicating that the IL-6 molecular pathway may represent a new target for monitoring and treating these conditions. Here, we report the detection of IL-6 in saliva samples from children (N = 118, mean age 4.4 years old) with behavioral problems using an immunosensor based on electrochemical impedance spectroscopy. This work demonstrates that the proposed immunosensor requires smaller sample volumes and is significantly faster and more sensitive than conventional ELISA while maintaining comparable levels of specificity and reproducibility. The point-of care immunosensor for detection of IL-6 in saliva samples presented herewith is, therefore, an attractive solution to the clinical practice as a rapid non-invasive, high-sensitive monitoring tool of mental health problems, especially in vulnerable patient populations such as children.

Inflammation in first-episode psychosis: The contribution of inflammatory biomarkers to the emergence of negative symptoms, a systematic review and meta-analysis

OBJECTIVE

To provide a comprehensive analysis of cytokine perturbations in antipsychotic-naïve first-episode psychosis (FEP) populations and assess the relationship between inflammatory biomarkers and negative symptom severity.

METHODS

A systematic review and meta-analysis following PRISMA guidelines were conducted. A total of 1042 records were identified via systematic search of EMBASE, MEDLINE and APA PsycInfo databases. Sixteen studies met the inclusion criteria and were eligible for inclusion in the review. Ten of these studies had sufficient data for inclusion in a random effects, pooled-effect meta-analysis.

RESULTS

A significant and large effect size was reported for IFN-γ, IL-6 and IL-12, and a moderate effect size reported for IL-17 (p = <0.05) in people with antipsychotic naive first episode psychosis, compared to healthy controls, suggesting a significant elevation in proinflammatory cytokine concentration. Non-significant effect sizes were reported for TNF-α, IL-1β, IL-2, IL-4, IL-8 and IL-10 (p = >0.05). Regarding proinflammatory cytokines and relationships to negative symptomology, moderate positive relationships were reported for negative symptoms and IL-1β, IL-2, IL-6 and TNF-α, across four studies. For anti-inflammatory cytokines, one strong and one weak-to-moderate negative relationship was described for IL-10 and negative symptoms. Contrastingly, a strong positive relationship was reported for IL-4 and negative symptoms.

CONCLUSION

There is evidence of significantly elevated proinflammatory cytokines in antipsychotic-naïve FEP populations, alongside promising findings from cohort data suggesting an interaction between inflammation and primary negative symptomology. Future studies should seek to come to a consensus on a panel of cytokines that relate most specifically to negative symptoms, and consider longitudinal studies to investigate how cytokine fluctuations may relate to exacerbation of symptoms.

Childhood trauma and the plasma levels of IL-6, TNF-α are risk factors for major depressive disorder and schizophrenia in adolescents: A cross-sectional and case-control study

BACKGROUND

It has been reported that childhood trauma and inflammation are associated with major depressive disorder (MDD) and schizophrenia (SZ), but previous researches were almost aimed at adults. The aim of the present research is to observe the alteration of peripheral interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in adolescents (12-20 years) with MDD and SZ, to investigate the impact of childhood abuse in early-onset MDD and SZ, and to furtherly explore the correlation between childhood maltreatment and plasma IL-6, TNF-α levels.

SUBJECTS AND METHODS

Enzyme-linked immunosorbent assay (ELISA) is applied to obtain the plasma concentrations of IL-6 and TNF-α in 55 patients with MDD, 51 patients with SZ and 47 healthy minors. The short form of the Childhood Trauma Questionnaire (CTQ-SF) is used to assess the severity of early trauma.

RESULTS

Plasma IL-6 and TNF-α levels are significantly elevated in patients with early-onset MDD and SZ compared with healthy subjects (p <0.01), whose results display that the correlation between IL-6 and TNF-α is significantly positive (γ=0.787, p <0.01) in all participants. Compared with the healthy adolescents, patients with MDD and SZ show more serious childhood trauma, and the plasma IL-6, TNF-α concentrations are closely related to childhood maltreatment.

CONCLUSIONS

Early trauma and peripheral inflammatory response play an important role in the pathophysiology of early-onset MDD or SZ. The current findings provide effective targets for the prevention, diagnosis, and treatment of major depressive disorder and schizophrenia in adolescents.

Role of Inflammation in Traumatic Brain Injury-Associated Risk for Neuropsychiatric Disorders: State of the Evidence and Where Do We Go From Here

In the past decade, there has been an increasing awareness that traumatic brain injury (TBI) and concussion substantially increase the risk for developing psychiatric disorders. Even mild TBI increases the risk for depression and anxiety disorders such as posttraumatic stress disorder by two- to threefold, predisposing patients to further functional impairment. This strong epidemiological link supports examination of potential mechanisms driving neuropsychiatric symptom development after TBI. One potential mechanism for increased neuropsychiatric symptoms after TBI is via inflammatory processes, as central nervous system inflammation can last years after initial injury. There is emerging preliminary evidence that TBI patients with posttraumatic stress disorder or depression exhibit increased central and peripheral inflammatory markers compared with TBI patients without these comorbidities. Growing evidence has demonstrated that immune signaling in animals plays an integral role in depressive- and anxiety-like behaviors after severe stress or brain injury. In this review, we will 1) discuss current evidence for chronic inflammation after TBI in the development of neuropsychiatric symptoms, 2) highlight potential microglial activation and cytokine signaling contributions, and 3) discuss potential promise and pitfalls for immune-targeted interventions and biomarker strategies to identify and treat TBI patients with immune-related neuropsychiatric symptoms.

Association of serum lipid levels with psychotic symptoms in first-episode and drug naïve outpatients with major depressive disorder: a large-scale cross-sectional study

Background Major depressive disorder (MDD) is a prevalent psychiatric disorder, with increasing evidence that patients with MDD display psychotic symptoms. Studies have shown the association between lipid levels and MDD, but few have explored the relationship between lipids and psychotic symptoms in MDD. The objective of this study was to compare the differences of lipid levels between patients with psychotic major depressive disorder (PMD) and those with non-psychotic major depressive disorder (NPMD) in first-episode and drug-naive (FEDN) MDD patients. Methods A total of 1718 outpatients with FEDN MDD were recruited. In addition to collecting basic information, their blood specimens were also collected to detect serum TC, HDL-C, TG, and LDL-C. The Hamilton depression scale (HAMD), Hamilton anxiety scale (HAMA), and Positive and Negative Syndrome Scale (PANSS) were used to assess their depression, anxiety, and psychotic symptoms respectively. Results Compared to those with NPMD, those with PMD had higher scores on HAMD, HAMA, and more elevated serum TC, TG, and LDL-C levels, but lower HDL-C levels (all p < 0.05). Further logistic regression analysis showed that TG, the severity of depressive and anxiety symptoms were significantly associated with psychotic symptoms (p < 0.05). Limitations No causal relationship could be drawn due to the cross-sectional design. Conclusions Psychotic symptoms in patients with MDD may be predicted by lipid levels in the future. Our findings suggest that TG seems to predict the presence of current psychotic features among patients with FEDN MDD.

Prenatal and Childhood Immuno-Metabolic Risk Factors for Adult Depression and Psychosis

Depression and psychosis have a developmental component to their origin. Epidemiologic evidence, which we synthesize in this nonsystematic review, suggests that early-life infection, inflammation, and metabolic alterations could play a role in the etiology of these psychiatric disorders. The risk of depression and psychosis is associated with prenatal maternal and childhood infections, which could be mediated by impaired neurodevelopment. Evidence suggests linear dose-response associations between elevated concentrations of circulating inflammatory markers in childhood, particularly the inflammatory cytokine interleukin 6, and the risk for depression and psychosis subsequently in early adulthood. Childhood inflammatory markers are also associated with persistence of depressive symptoms subsequently in adolescence and early adulthood. Developmental trajectories reflecting persistently high insulin levels during childhood and adolescence are associated with a higher risk of psychosis in adulthood, whereas increased adiposity during and after puberty is associated with the risk of depression. Together, these findings suggest that higher levels of infection, inflammation, and metabolic alterations commonly seen in people with depression and psychosis could be a cause for, rather than simply a consequence of, these disorders. Therefore, early-life immuno-metabolic alterations, as well as factors influencing these alterations such as adversity or maltreatment, could represent targets for prevention of these psychiatric disorders. Inflammation could also be an important treatment target for depression and psychosis. The field requires further research to examine sensitive periods when exposure to such immuno-metabolic alterations is most harmful. Interventional studies are also needed to test the potential usefulness of targeting early-life immuno-metabolic alterations for preventing adult depression and psychosis.

Longitudinal association between CRP levels and risk of psychosis: a meta-analysis of population-based cohort studies

Meta-analyses of cross-sectional studies suggest that patients with psychosis have higher circulating levels of C-reactive protein (CRP) compared with healthy controls; however, cause and effect is unclear. We examined the prospective association between CRP levels and subsequent risk of developing a psychotic disorder by conducting a systematic review and meta-analysis of population-based cohort studies. Databases were searched for prospective studies of CRP and psychosis. We obtained unpublished results, including adjustment for age, sex, body mass index, smoking, alcohol use, and socioeconomic status and suspected infection (CRP > 10 mg/L). Based on random effect meta-analysis of 89,792 participants (494 incident cases of psychosis at follow-up), the pooled odds ratio (OR) for psychosis for participants with high (>3 mg/L), as compared to low (≤3 mg/L) CRP levels at baseline was 1.50 (95% confidence interval [CI], 1.09-2.07). Evidence for this association remained after adjusting for potential confounders (adjusted OR [aOR] = 1.31; 95% CI, 1.03-1.66). After excluding participants with suspected infection, the OR for psychosis was 1.36 (95% CI, 1.06-1.74), but the association attenuated after controlling for confounders (aOR = 1.23; 95% CI, 0.95-1.60). Using CRP as a continuous variable, the pooled OR for psychosis per standard deviation increase in log(CRP) was 1.11 (95% CI, 0.93-1.34), and this association further attenuated after controlling for confounders (aOR = 1.07; 95% CI, 0.90-1.27) and excluding participants with suspected infection (aOR = 1.07; 95% CI, 0.92-1.24). There was no association using CRP as a categorical variable (low, medium or high). While we provide some evidence of a longitudinal association between high CRP (>3 mg/L) and psychosis, larger studies are required to enable definitive conclusions.

COVID-19 in People With Schizophrenia: Potential Mechanisms Linking Schizophrenia to Poor Prognosis

As the global burden of mortality from COVID-19 continues to rise, an understanding of who is most at risk of adverse outcomes is of paramount importance. Pre-existing cardiometabolic, renal and respiratory diseases as well as old age are well-established risk factors associated with disease severity and mortality among patients with COVID-19. However, mounting evidence also indicates an increased susceptibility to, and risk of adverse outcomes from COVID-19 in people with schizophrenia, independent of age and comorbidity. Therefore, elucidating the underlying pathophysiological mechanisms which may increase the risk of poor outcomes in people with schizophrenia is of crucial importance. Here, we provide a narrative on the current understanding of COVID-19 in patients with schizophrenia and propose potential mechanisms which may link schizophrenia with an increased susceptibility to, and greater risk of adverse outcomes from COVID-19. Given the existing knowledge gaps, robust clinical and biological studies are required to further our understanding of some of these underlying mechanisms, so that effective prevention and treatment strategies for COVID-19 in patients with schizophrenia can be developed.