Annual Research Review: Neuroimmune network model of depression: a developmental perspective

Machine learning-driven risk prediction and feature identification for major depressive disorder and its progression: an exploratory study based on five years of longitudinal data from the US national health survey

BACKGROUND

Major depressive disorder (MDD) presents significant public health challenges due to its increasing prevalence and complex risk factors. This study systematically analyzed data from 2019 to 2023 to explore trends in MDD incidence, symptom progression, and multidimensional influencing factors.

OBJECTIVE

The study aimed to identify key risk factors and mechanisms of MDD progression through multidimensional variable analysis and machine learning model evaluation, optimizing predictive models to provide a scientific basis for early screening, targeted interventions, and public health policy formulation.

METHODS

Data from the U.S. National Health Interview Survey (NHIS) were analyzed using LASSO regression for feature selection and various machine learning models (e.g., AdaBoost, Gradient Boosting, Gaussian NB, Extra Trees) for risk prediction. SHAP value analysis was employed to interpret the models and identify key predictors across psychological, social, and biological domains.

RESULTS

Depression risk was closely associated with psychological health (e.g., PHQ82, ANXLEVEL), social support (e.g., DISCRIM1, PCNTADLT), and biological health (e.g., COGMEMDFF, DEPEV). AdaBoost, Gradient Boosting, Gaussian NB, and Extra Trees demonstrated superior performance in different tasks, with SHAP analysis highlighting the critical role of psychological health in risk prediction and the importance of social support and cognitive deficits in symptom progression.

CONCLUSIONS

This study provides a scientific foundation for early screening of MDD, personalized intervention strategies, and public health policy optimization. Future research should expand data coverage, optimize models, and incorporate causal inference methods to enhance the precision and applicability of depression risk prediction.

Differential immune profiles in the context of chronic stress among childhood adversity-exposed adolescents

Psychosocial stress has been linked to myriad mental and physical health conditions. Stress-induced changes to functioning of the immune system is a plausible mechanism in this association. Psychosocial stress is a well-established contributor to immune dysregulation, though the extant literature to date falls short of addressing the role of distal relative to contemporary stress in immune function, particularly as they relate to distinctions between innate and adaptive immunity. The present study directly addressed this knowledge gap by characterizing vertically-integrated markers of immune functioning as a function of both recent chronic stress during adolescence and childhood adversity. In the present study, childhood adversity (before age 10) and recent psychosocial stressors (past 6 months) were characterized via semi-structured clinical interviews among 127 adolescent girls (aged 13-17; 31 % Black, 38 % Hispanic, 32 % NHW) who have all measures included in this report. Vertically-integrated markers of immune activity were also collected: an a priori subset of immune-related genes using genome-wide transcriptional profiling, an 11-plex of circulating cytokines (IL-6, TNF-α, IL-10, IL-8, IFN-γ, IL-1β, IL-1α, IL-27, MCP-1, IL-12p70, IP-10), and systemic inflammation (C-reactive protein; CRP). The association between recent chronic stress and intracellular immune outcomes differed based on childhood adversity. Genome-wide transcriptional profiling implicated myeloid lineage cells, specifically monocytes and dendritic cells, in differential patterns of gene expression among childhood adversity-exposed youth in the context of chronic stress. These differential patterns were also reflected in expression of proinflammatory genes and CRP such that among adolescents without exposure to childhood adversity, more recent chronic stress was associated with less proinflammatory gene expression, b = -0.45 (SE = 0.22), p = 0.04, 95 %CI [-0.87, -0.02], and somewhat higher CRP, b = 0.62 (SE = 0.35), p = 0.08, 95 %CI [-0.07, 1.31], while among adolescents with exposure to childhood adversity, more recent chronic stress was not associated with any immune activity markers. However, these patterns among circulating markers did not survive corrections for multiple comparisons. Immune adaptation in the context of chronic stress may indicate plasticity to environmental demands that conserves biological resources, which may be a source of resilience that is negatively impacted by childhood adversity.

Molecular imprinted photoresponse hybrid biocatalyst for ultrasensitive glutamate detection

A novel construction strategy for hybrid nanobiocatalyst was developed in this study by combining molecular imprinting technology with Fe3O4 nanoparticles hybrid MOF and enzyme immobilization technology. The impacts of molecular imprinting and the photothermal effect of Fe3O4 were investigated on the catalytic performance of the hybrid nanobiocatalyst. It was demonstrated that Fe3O4 nanoparticles exhibited a photothermal effect when exposed to multi-wavelength light. Leveraging the selective recognition ability of the molecular imprinting technique, the hybrid nanobiocatalyst showed a 15.8 % increase in catalytic activity for glutamate oxidase. Furthermore, under the influence of red light (650 nm), the photothermal effect induced by Fe3O4 accelerated the enzymatic reaction rate, resulting in a 23 % increase in enzyme activity. Benefiting from the specific recognition of the substrate by the Fe3O4 imprinted polymer, the hybrid nanobiocatalyst exhibited the rapid and highly sensitive detection of glutamate. Notably, this work provides an efficient strategy for constructing hybrid nanobiocatalyst with excellent properties.

Reward Processing in Mood Disorders and Schizophrenia: A Neurodevelopmental Framework

Major depressive disorder (MDD), bipolar disorder, and schizophrenia involve disruptions in processing rewarding stimuli. In this review, we propose that distinct mechanistic pathways underlie these disruptions in mood disorders versus schizophrenia, and we highlight the importance of understanding these differences for developing personalized treatments. We summarize evidence suggesting that reward processing abnormalities in mood disorders are driven by dysregulated motivational systems; MDD is characterized by blunted responses to reward cues, and bipolar disorder is characterized by heightened responses. In contrast, we argue that reward processing disruptions in schizophrenia do not reflect abnormalities in motivation or hedonic experience; rather, they reflect impairments in the cognitive representation of past and future rewards as well as misdirected attention to irrelevant stimuli. To integrate these findings, we present a neurodevelopmental framework for the onset of mood and psychotic disorders and explore how disruptions in normative brain development contribute to their pathophysiology, timing, and onset. Additionally, we move beyond viewing these conditions as homogeneous disorders and discuss how reward processing profiles may align with specific symptom dimensions.

A Phenome-Wide association study (PheWAS) of genetic risk for C-reactive protein in children of European Ancestry: Results from the ABCD study

BACKGROUND

C-reactive protein (CRP) is a moderately heritable marker of systemic inflammation that is associated with adverse physical and mental health outcomes. Identifying factors associated with genetic liability to elevated CRP in childhood may inform our understanding of variability in CRP that could be targeted to prevent and/or delay the onset of related health outcomes.

METHODS

We conducted a phenome-wide association study (PheWAS) of genetic risk for elevated CRP (i.e. CRP polygenic risk score [PRS]) among children genetically similar to European ancestry reference populations (median analytic n = 5,509, range = 120-5,556) from the Adolescent Brain and Cognitive DevelopmentSM (ABCD) Study baseline assessment. Associations between CRP PRS and 2,377 psychosocial and neuroimaging phenotypes were estimated using independent mixed effects models nested by recruitment site (or scanner) and family, with ancestral genomic principal components (n = 10), age, and sex, as well as global brain metrics (when relevant) included as fixed effect covariates. Post hoc analyses examined whether: (1) covarying for measured body mass index (BMI) or removing the shared genetic architecture between CRP and BMI altered phenotypic associations, (2) sex moderated CRP PRS associations, and (3) associations were unconfounded by assortative mating or passive gene-environment correlations (using within-family analyses). Multiple testing was adjusted for using Bonferroni and false discovery rate (FDR) correction.

RESULTS

Nine phenotypes were positively associated with CRP PRS after multiple testing correction: five weight- and eating-related phenotypes (e.g. BMI, overeating), three phenotypes related to caregiver somatic problems (e.g. caregiver somatic complaints), as well as weekday video watching (all ps = 1.2 x 10-7 - 2.5 x 10-4, all pFDRs = 0.0002-0.05). No neuroimaging phenotypes were associated with CRP PRS (all ps = 0.0003-0.998; all pFDRs = 0.08-0.998) after correction for multiple testing. Eating and weight-related phenotypes remained associated with CRP PRS in within-family analyses. Covarying for BMI resulted in largely consistent results, and sex did not moderate any CRP PRS associations. Removing the shared genetic variance between CRP and BMI attenuated all relationships; associations with weekday video watching, caregiver somatic problems and caregiver report that the child is overweight remained significant while associations with waist circumference, weight, and caregiver report that child overeats did not.

DISCUSSION

Genetic liability to elevated CRP is associated with higher weight, eating, and weekday video watching during childhood as well as caregiver somatic problems. These associations were consistent with direct genetic effects (i.e., not solely due to confounding factors like passive gene-environment correlations) and were independent of measured BMI. The majority of associations with weight and eating phenotypes were attributable to shared genetic architecture between BMI and inflammation. The relationship between genetics and heightened inflammation in later life may be partially attributable to modifiable behaviors (e.g. weight and activity levels) that are expressed as early as childhood.

Higher inflammatory proteins predict future depressive symptom severity among adolescents with lower emotional clarity

BACKGROUND

A growing body of work has implicated inflammation in the pathogenesis of depression. As not all individuals with heightened levels of peripheral inflammation develop symptoms of depression, additional work is needed to identify other factors that catalyze the relationship between inflammation and depressive symptoms. Given that elevated levels of inflammatory activity can induce a variety of emotional changes, the present study examined whether emotional clarity, the trait-like ability to identify, discern, and express one's emotions, influences the strength of the association between inflammatory signaling and concurrent and prospective symptoms of depression.

METHODS

Community adolescents (N = 225, Mage = 16.63 years), drawn from a larger longitudinal project investigating sex and racial differences in depression onset, provided blood samples to determine peripheral levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP) at a baseline visit, along with self-report measures of emotional clarity and depressive symptom severity. Depressive symptom severity was assessed again at a follow-up visit approximately 5-months after baseline.

RESULTS

Hierarchical multiple regressions detected a significant interaction between inflammatory markers and emotional clarity on future depression severity, controlling for baseline depressive symptoms. Specifically, among adolescents with low levels of emotional clarity, higher levels of IL-6, CRP, and inflammatory composite scores were significantly associated with greater future depression severity.

CONCLUSIONS

These results indicate that low emotional clarity and high inflammatory signaling may jointly confer risk for prospective depressive symptom severity among adolescents. Therapeutic interventions that improve emotional clarity may reduce risk of depressive symptoms among adolescents with low-grade peripheral inflammation.

Spatial maps in piriform cortex during olfactory navigation

Odors are a fundamental part of the sensory environment used by animals to inform behaviors such as foraging and navigation1,2. Primary olfactory (piriform) cortex is thought to be dedicated to encoding odor identity3-8. Here, using neural ensemble recordings in freely moving rats performing a novel odor-cued spatial choice task, we show that posterior piriform cortex neurons also carry a robust spatial map of the environment. Piriform spatial maps were stable across behavioral contexts independent of olfactory drive or reward availability, and the accuracy of spatial information carried by individual neurons depended on the strength of their functional coupling to the hippocampal theta rhythm. Ensembles of piriform neurons concurrently represented odor identity as well as spatial locations of animals, forming an "olfactory-place map". Our results reveal a previously unknown function for piriform cortex in spatial cognition and suggest that it is well-suited to form odor-place associations and guide olfactory cued spatial navigation.

A Phenome-Wide Association Study (PheWAS) of Genetic Risk for C-Reactive Protein in Children of European Ancestry: Results From the ABCD Study

BACKGROUND

C-reactive protein (CRP) is a moderately heritable marker of systemic inflammation that is associated with adverse physical and mental health outcomes. Identifying factors associated with genetic liability to elevated CRP in childhood may inform our understanding of variability in CRP that could be targeted to prevent and/or delay the onset of related health outcomes.

METHODS

We conducted a phenome-wide association study (PheWAS) of genetic risk for elevated CRP (i.e. CRP polygenic risk score [PRS]) among children genetically similar to European ancestry reference populations (median analytic n = 5,509) from the Adolescent Brain and Cognitive Development℠ (ABCD) Study. Associations between CRP PRS and 2,377 psychosocial and neuroimaging phenotypes were estimated using independent mixed effects models. Post hoc analyses examined whether: (1) covarying for measured body mass index (BMI) or removing the shared genetic architecture between CRP and BMI altered phenotypic associations, (2) sex moderated CRP PRS associations, and (3) associations are unconfounded by assortative mating or passive gene-environment correlations (using a within-family analyses). Multiple testing was adjusted for using Bonferroni and false discovery rate (FDR) correction.

RESULTS

Nine phenotypes were positively associated with CRP PRS after multiple testing correction: five weight- and eating-related phenotypes (e.g. BMI, overeating), three phenotypes related to caregiver somatic problems (e.g. caregiver somatic complaints), as well as weekday video watching (all ps = 1.2 × 10-7 - 2.5 × 10-4, all p FDR s = 0.0002 - 0.05). No neuroimaging phenotypes were associated with CRP PRS (all ps = 0.0003 - 0.998; all p FDR s = 0.08 - 0.998) after correction for multiple testing. Eating and weight-related phenotypes remained associated with CRP PRS in within-family analyses. Covarying for BMI resulted in largely consistent results, and sex did not moderate any CRP PRS associations. Removing the shared genetic variance between CRP and BMI attenuated all relationships; associations with weekday video watching, caregiver somatic problems and caregiver report that the child is overweight remained significant while associations with waist circumference, weight, and caregiver report that child overeats did not.

DISCUSSION

Genetic liability to elevated CRP is associated with higher weight, eating, and weekday video watching during childhood as well as caregiver somatic problems. These associations were consistent with direct genetic effects (i.e., not solely due to confounding factors like passive gene-environment correlations) and were independent of measured BMI. The majority of associations with weight and eating phenotypes were attributable to shared genetic architecture between BMI and inflammation. The relationship between genetics and heightened inflammation in later life may be partially attributable to modifiable behaviors (e.g. weight and activity levels) that are expressed as early as childhood.

Higher substance use is associated with low executive control neural activity and higher inflammation

Individuals with substance use problems show lower executive control and alterations in prefrontal brain systems supporting emotion regulation and impulse control. A separate literature suggests that heightened inflammation also increases risk for substance use, in part, through targeting brain systems involved in executive control. Research on neural and inflammatory signaling in substance use, however, has occurred in parallel. Drawing on recent neuroimmune network models, we used fMRI to examine the relationships between executive control-related brain activity (as elicited by an n-back working memory task), peripheral inflammation, as quantified by inflammatory cytokines and C-reactive protein (CRP), and substance use for the past month in 93 participants [mean age = 24.4 (SD = 0.6)]. We operationalized low executive control as a neural inefficiency during the n-back task to achieve normative performance, as reflected in higher working memory-related brain activity and lower activity in the default mode network (DMN). Consistent with prediction, individuals with low executive control and high inflammation reported more substance use over the past month, controlling for behavioral performance on the n-back, sex, time between assessments, body-mass-index (BMI), and personal socioeconomic status (SES) (interaction between inflammation and working memory-related brain activity, b = 0.210, p = 0.005; interaction between inflammation and DMN, b = -0.219, p < 0.001). Findings suggest that low executive control and high inflammation may be associated with higher substance use. This has implications for understanding psychological, neural, and immunological risk for substance use problems and the development of interventions to target each of these components.

Estrogen-immuno-neuromodulation disorders in menopausal depression

A significant decrease in estrogen levels puts menopausal women at high risk for major depression, which remains difficult to cure despite its relatively clear etiology. With the discovery of abnormally elevated inflammation in menopausal depressed women, immune imbalance has become a novel focus in the study of menopausal depression. In this paper, we examined the characteristics and possible mechanisms of immune imbalance caused by decreased estrogen levels during menopause and found that estrogen deficiency disrupted immune homeostasis, especially the levels of inflammatory cytokines through the ERα/ERβ/GPER-associated NLRP3/NF-κB signaling pathways. We also analyzed the destruction of the blood-brain barrier, dysfunction of neurotransmitters, blockade of BDNF synthesis, and attenuation of neuroplasticity caused by inflammatory cytokine activity, and investigated estrogen-immuno-neuromodulation disorders in menopausal depression. Current research suggests that drugs targeting inflammatory cytokines and NLRP3/NF-κB signaling molecules are promising for restoring homeostasis of the estrogen-immuno-neuromodulation system and may play a positive role in the intervention and treatment of menopausal depression.

Adding to the neuroimmune network model: A commentary on Nusslock et al. (2024)

Work by many groups demonstrate links between peripheral markers of inflammation and symptoms of depression. Here, Nusslock and colleagues present an update to their neuroimmune network model to incorporate a developmental lens. They propose that specific neural circuits may be responsible for causing heightened inflammation. One principal circuit includes the amygdala and prefrontal cortex and is proposed to be involved in threat detection. Thus, heightened threat sensitivity resulting from early life stress is suggested to cause increases in inflammatory signaling. Second, the authors suggest that reward circuits, including the striatum, may be targets of increased inflammation leading to symptoms of anhedonia. In this commentary, I add context to the model proposed by Nusslock et al., suggesting that taking a learning perspective and considering additional circuits, including the hippocampus and midline structures may be necessary to more fully account for the phenomena described by the authors.