1
|
Foley ÉM, Slaney C, Donnelly NA, Kaser M, Ziegler L, Khandaker GM. A novel biomarker of interleukin 6 activity and clinical and cognitive outcomes in depression. Psychoneuroendocrinology 2024; 164:107008. [PMID: 38442505 DOI: 10.1016/j.psyneuen.2024.107008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 02/05/2024] [Accepted: 02/26/2024] [Indexed: 03/07/2024]
Abstract
BACKGROUND Inflammatory cytokines like interleukin-6 (IL-6) are implicated in depression, but most studies have hitherto focused on circulating levels of IL-6 rather than its activity. IL-6 trans-signalling is thought to be responsible for most of the pathogenic effects of IL-6 and is implicated in autoimmune diseases like rheumatoid arthritis. We tested the association between a multi-protein-derived measure of IL-6 trans-signalling and clinical and cognitive outcomes in patients with depression. We hypothesised that this novel measure of IL-6 activity/bioavailability would be associated with clinical and cognitive measures previously reported to be associated with inflammation in depression. METHODS Using data from 86 patients with International Classification of Diseases-10 diagnosis of depression, we calculated a ratio score representing IL-6 activity/bioavailability using serum IL-6, soluble IL-6 receptor (sIL-6R), and soluble glycoprotein 130 levels. We tested the relationship of this novel biomarker with 12 cytokines using correlation analyses and with cognitive and clinical measures using multivariable linear regression, following z-transformation of all immune exposures. RESULTS The novel measure of IL-6 activity/bioavailability was correlated with IL-6 (r=0.42, P=0.03), C-reactive protein (CRP) (r=0.42, P=0.03), sIL-6R (r=0.91, P<0.01), and tumour necrosis factor alpha (r=0.43, P=0.03). The IL-6 activity/bioavailability measure was associated with higher somatic symptoms of depression (β=1.09; 95% CI 0.30, 1.88; PFDR=0.01), fatigue (β=4.34; 95% CI 1.26, 7.42; PFDR=0.03), depression severity (β=3.06; 95% CI 0.71, 5.40; P=0.02), poorer quality of life (β=-0.07; 95% CI -0.13, -0.01; PFDR=0.045), and decreased psychomotor speed (β=-5.46; 95% CI -9.09, -1.84; PFDR=0.01),. There was little evidence of associations with reaction time, anhedonia, anxiety, emotional perception and recall, executive function, and sustained attention (Ps>0.05). The effect estimates for the associations of the novel measure with depression outcomes were comparable to those for individual immune proteins (i.e., IL-6, CRP, sIL-6R). CONCLUSION A novel multi-protein-derived measure of IL-6 activity/bioavailability shows robust associations with various inflammation-related clinical and cognitive outcomes in depression and performs well in comparison to single inflammatory proteins. We need replication of these findings in other samples, experiments for mechanistic validity of this novel biomarker, and clinical studies to assess its usefulness as a marker of illness risk and prognosis.
Collapse
Affiliation(s)
- Éimear M Foley
- MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK; Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK.
| | - Chloe Slaney
- MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK; Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Nicholas A Donnelly
- MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK; Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK; Avon and Wiltshire Mental Health Partnership NHS Trust, Bristol, UK
| | - Muzaffer Kaser
- Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK; Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Louise Ziegler
- Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Golam M Khandaker
- MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK; Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK; Avon and Wiltshire Mental Health Partnership NHS Trust, Bristol, UK; NIHR Bristol Biomedical Research Centre, Bristol, UK
| |
Collapse
|
2
|
Yuan JP, Coury SM, Ho TC, Gotlib IH. Early life stress moderates the relation between systemic inflammation and neural activation to reward in adolescents both cross-sectionally and longitudinally. Neuropsychopharmacology 2024; 49:532-540. [PMID: 37673968 PMCID: PMC10789786 DOI: 10.1038/s41386-023-01708-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 07/27/2023] [Accepted: 08/09/2023] [Indexed: 09/08/2023]
Abstract
Elevated levels of systemic inflammation are associated with altered reward-related brain function in ventral striatal areas of the brain like the nucleus accumbens (NAcc). In adolescents, cross-sectional research indicates that exposure to early life stress (ELS) can moderate the relation between inflammation and neural activation, which may contribute to atypical reward function; however, no studies have tested whether this moderation by ELS of neuroimmune associations persists over time. Here, we conducted a cross-sectional analysis and the first exploratory longitudinal analysis testing whether cumulative severity of ELS moderates the association of systemic inflammation with reward-related processing in the NAcc in adolescents (n = 104; 58F/46M; M[SD] age = 16.00[1.45] years; range = 13.07-19.86 years). For the cross-sectional analysis, we modeled a statistical interaction between ELS and levels of C-reactive protein (CRP) predicting NAcc activation during the anticipation and outcome phases of a monetary reward task. We found that higher CRP was associated with blunted NAcc activation during the outcome of reward in youth who experienced higher levels of ELS (β = -0.31; p = 0.006). For the longitudinal analysis, we modeled an interaction between ELS and change in CRP predicting change in NAcc activation across 2 years. This analysis similarly showed that increasing CRP over time was associated with decreasing NAcc during reward outcomes in youth who experienced higher levels of ELS (β = -0.47; p = 0.022). Both findings support contemporary theoretical frameworks involving associations among inflammation, reward-related brain function, and ELS exposure, and suggest that experiencing ELS can have significant and enduring effects on neuroimmune function and adolescent neurodevelopment.
Collapse
Affiliation(s)
- Justin P Yuan
- Department of Psychology, Stanford University, Stanford, CA, USA.
| | - Saché M Coury
- Department of Psychology, Stanford University, Stanford, CA, USA
| | - Tiffany C Ho
- Department of Psychology, University of California, Los Angeles, CA, USA
| | - Ian H Gotlib
- Department of Psychology, Stanford University, Stanford, CA, USA
| |
Collapse
|
3
|
Walsh RFL, Klugman J, Moriarity DP, Titone MK, Ng TH, Goel N, Alloy LB. Reward sensitivity and social rhythms during goal-striving: An ecological momentary assessment investigation of bipolar spectrum disorders. J Affect Disord 2024; 344:510-518. [PMID: 37852584 PMCID: PMC10842638 DOI: 10.1016/j.jad.2023.10.114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 10/12/2023] [Accepted: 10/15/2023] [Indexed: 10/20/2023]
Abstract
BACKGROUND The reward/circadian rhythm model of bipolar spectrum disorders (BSDs) posits that when individuals with hypersensitive reward systems encounter reward-relevant events, they experience social and circadian rhythm disruption, leading to mood symptoms. The aim of the current study is to test an element of this theoretical model by investigating changes in social rhythms during and after an ecologically-valid reward-relevant event and evaluating whether the strength of these associations differ by trait reward sensitivity and BSD diagnostic group. METHODS Young adults from three groups (low BSD risk with moderate reward sensitivity [MRew], high BSD risk with high reward sensitivity [HRew], and high reward sensitivity with BSD [HRew+BSD]) completed a reward responsiveness task and 20-day ecological momentary assessment study structured around a participant-specific goal occurring on day 15. Social rhythm disruption (SRD) and social rhythm regularity (SRR) were assessed daily. Multilevel models examined whether reward sensitivity and group moderated associations between study phase (baseline [days 1-5], goal-striving [days 16-20], or outcome [days 16-20]) and social rhythms. RESULTS Participants experienced greater SRD after the goal-striving event during the outcome phase, compared to the baseline phase. The HRew+BSD group had significant decreases in SRR during the outcome phase, and this pattern differed significantly from the low-risk and high-risk groups. Greater task reward responsiveness also was associated with significant decreases in SRR during the outcome phase. LIMITATIONS This study did not test whether social rhythm irregularity was associated with subsequent mood change. CONCLUSIONS Participants exhibited social rhythm changes over the course of this ecologically valid goal-striving period, providing evidence for the interplay between reward-activating events and social rhythms. The HRew+BSD group showed a distinct pattern in which their social rhythms were more irregular after completing reward-relevant goal-striving that was not observed for the low-BSD risk or high-BSD risk groups. These findings provide additional support for Interpersonal and Social Rhythms Therapy.
Collapse
Affiliation(s)
- Rachel F L Walsh
- Department of Psychology and Neuroscience, Temple University, United States of America
| | - Joshua Klugman
- Department of Psychology and Neuroscience, Temple University, United States of America; Department of Sociology, Temple University, United States of America
| | - Daniel P Moriarity
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, United States of America
| | - Madison K Titone
- VA San Diego Healthcare System, United States of America; University of California San Diego, United States of America
| | - Tommy H Ng
- Department of Psychiatry, Weill Cornell Medicine College, United States of America
| | - Namni Goel
- Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, United States of America
| | - Lauren B Alloy
- Department of Psychology and Neuroscience, Temple University, United States of America.
| |
Collapse
|
4
|
Alloy LB, Chat IKY, Grehl MM, Stephenson AR, Adogli ZV, Olino TM, Ellman LM, Miller GE, Nusslock R. Reward and Immune Systems in Emotion (RISE) prospective longitudinal study: Protocol overview of an integrative reward-inflammation model of first onset of major depression in adolescence. Brain Behav Immun Health 2023; 30:100643. [PMID: 37304334 PMCID: PMC10250584 DOI: 10.1016/j.bbih.2023.100643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 05/22/2023] [Indexed: 06/13/2023] Open
Abstract
Background Depression is associated with a reduced sensitivity to rewards and low reward-related brain function in cortico-striatal circuitry. A separate literature documents elevated peripheral inflammation in depression. Recently, integrated reward-inflammation models of depression have been proposed. These models draw on work indicating that peripheral inflammatory proteins access the brain, where they lower reward responsiveness. This blunted reward responsiveness is proposed to initiate unhealthy behaviors (substance use, poor diet), as well as sleep disruption and stress generation, which further heighten inflammation. Over time, dysregulation in reward responsiveness and immune signaling may synergize in a positive feedback loop, whereby dysregulation in each system exacerbates dysregulation in the other. Project RISE (Reward and Immune Systems in Emotion) provides a first systematic test of reward-immune dysregulation as a synergistic and dynamic vulnerability for first onset of major depressive disorder and increases in depressive symptoms during adolescence. Methods This NIMH-funded R01 study is a 3-year prospective, longitudinal investigation of approximately 300 community adolescents from the broader Philadelphia area, United States of America. Eligible participants must be 13-16 years old, fluent in English, and without a prior major depressive disorder. They are being selected along the entire dimension of self-reported reward responsiveness, with oversampling at the low tail of the dimension in order to increase the likelihood of major depression onsets. At Time 1 (T1), T3, and T5, each a year apart, participants complete blood draws to quantify biomarkers of low-grade inflammation, self-report and behavioral measures of reward responsiveness, and fMRI scans of reward neural activity and functional connectivity. At T1-T5 (with T2 and T4 six months between the yearly sessions), participants also complete diagnostic interviews and measures of depressive symptoms, reward-relevant life events, and behaviors that increase inflammation. Adversity history is assessed at T1 only. Discussion This study is an innovative integration of research on multi-organ systems involved in reward and inflammatory signaling in understanding first onset of major depression in adolescence. It has the potential to facilitate novel neuroimmune and behavioral interventions to treat, and ideally prevent, depression.
Collapse
Affiliation(s)
- Lauren B. Alloy
- Department of Psychology and Neuroscience, Temple University, USA
| | - Iris K.-Y. Chat
- Department of Psychology and Neuroscience, Temple University, USA
| | - Mora M. Grehl
- Department of Psychology and Neuroscience, Temple University, USA
| | | | - Zoe V. Adogli
- Department of Psychology and Neuroscience, Temple University, USA
| | - Thomas M. Olino
- Department of Psychology and Neuroscience, Temple University, USA
| | - Lauren M. Ellman
- Department of Psychology and Neuroscience, Temple University, USA
| | | | | |
Collapse
|
5
|
Rengasamy M, Nance M, Eckstrand K, Forbes E. Splitting the reward: Differences in inflammatory marker associations with neural connectivity between reward anticipation and reward outcome in adolescents at high risk for depression. J Affect Disord 2023; 327:128-136. [PMID: 36736795 DOI: 10.1016/j.jad.2023.01.118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 01/22/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023]
Abstract
BACKGROUND Adolescent depression is associated with both dysfunction in neural reward processing and peripheral inflammatory markers (PIMs), such as interleukin-6 (IL-6), C-reactive-protein (CRP), and tumor-necrosis factor alpha (TNFα). Few adolescent studies have examined neural-inflammatory marker associations and associated behavioral correlates, which would contribute to a better understanding of developmental processes linked to depression. METHODS 36 adolescents at high risk of depression completed an fMRI reward task (during anticipation and outcome), blood draw for PIMs (IL-6, CRP, and TNFα), and a behavioral task assessing motivation to expend effort. Analyses examined associations of task-dependent functional connectivity (FC; ventral striatum to frontal and default mode network brain regions), and if the interaction of PIMs and task-dependent FC predicted motivation to expend effort. RESULTS For anticipation contrast, TNFα was associated with increased task-dependent FC between the LVS and PCC/vmPFC. In moderation analyses, for anticipation contrasts, the combination of higher IL-6 and stronger FC (LVS-precuneus/PCC) was associated with lower motivation to expend effort, while for outcome contrasts, the combination of higher IL-6 and stronger FC (VS-precuneus/PCC) was associated with greater motivation to expend effort. CONCLUSIONS Our findings in adolescents during an important developmental time period suggest that PIMs are directly linked to greater FC between the VS and DMN brain regions during win anticipation, consistent with prior studies. Effects of PIMs on motivation to expend effort may vary the strength/type of neural reward processing (anticipation or outcome), which could guide better understanding how inflammatory markers and neural reward substrates contribute to development of depression in high-risk adolescents.
Collapse
Affiliation(s)
- Manivel Rengasamy
- University of Pittsburgh, Department of Psychiatry, United States of America.
| | - Melissa Nance
- University of Pittsburgh, Department of Psychiatry, United States of America
| | - Kristen Eckstrand
- University of Pittsburgh, Department of Psychiatry, United States of America
| | - Erika Forbes
- University of Pittsburgh, Department of Psychiatry, United States of America
| |
Collapse
|
6
|
Moriarity DP, Kautz MM, Ghias K, Pennypacker K, Harmon-Jones E, Alloy LB. Protocol for project MIME: Motivation, inflammation, and Mood in Emerging Adults. Brain Behav Immun Health 2022; 26:100520. [PMID: 36187406 PMCID: PMC9523276 DOI: 10.1016/j.bbih.2022.100520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 09/18/2022] [Indexed: 11/04/2022] Open
Abstract
Background Atypical inflammatory biology is gaining evidence as a risk factor for mood psychopathology; however, little work has attempted to integrate inflammation into extant psychosocial frameworks of risk. Recent work using secondary data analysis has investigated the possibility of an immunocognitive model of mood disorders, in which cognitive vulnerabilities (i.e., rumination on positive or negative affect) increase the effect that arousal-related characteristics (e.g., reward sensitivity) have on inflammatory biology in ways that may confer risk for depression and hypo/mania symptoms. Project MIME (Motivation, Inflammation, and Mood in Emerging Adults) was designed to test this model in the context of a novel, reward-salient stressor (the Anger Incentive Delay Task, AIDT). Methods This NIMH-funded study will result in a dataset of approximately 100 college undergraduates from a large university in Pennsylvania, United States of America. Eligible participants are recruited from an online screener, have to be 18–22 years old, fluent in English, and successfully answer several items designed to test whether participants randomly answer questions on the screener. Eligible participants are invited to an in-person visit in which they completed the AIDT, blood draws pre- and 50 minutes post-AIDT, and self-report questionnaires. Participants also complete a set of online questionnaires two weeks after the in-person visit. Discussion Consistent with calls from the NIH director, this study seeks to diversify the tools used in stress research by validating a novel reward-salient stressor (in contrast to the field's reliance on social stressors) with respect to affective and immunological stress reactivity. In addition to this methodological goal, Project MIME is the first study specifically designed to test the immunocognitive model of mood psychopathology. Given the integration of several malleable treatment targets (approach behavior, emotion regulation, inflammation) into this model, results from this study could inform comprehensive, flexible intervention strategies for mood disorder prevention and treatment.
Collapse
|
7
|
Wang L, Yin Y, Feng W, Zhou Y, Huang J, Zhang P, Chen S, Fan H, Cui Y, Luo X, Tan S, Wang Z, Tian B, Tian L, Li CSR, Tan Y. Childhood trauma and cognitive deficits in patients with schizophrenia: mediation by orbitofrontal cortex H-shaped sulci volume. J Psychiatry Neurosci 2022; 47:E209-E217. [PMID: 35654451 PMCID: PMC9177195 DOI: 10.1503/jpn.210178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 02/27/2022] [Accepted: 03/15/2022] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND A line of evidence has shown that childhood trauma and patterns of H-shaped sulci in the orbitofrontal cortex (OFC) are associated with cognitive deficits in patients with schizophrenia. Studies have also suggested that childhood trauma is associated with OFC volumetrics. This study investigated the interrelationship between childhood trauma, OFC H-shaped sulci volume and cognitive function in patients with first-episode schizophrenia. We hypothesized that OFC H-shaped sulci volume would mediate the relationship between childhood trauma and cognitive function in patients with first-episode schizophrenia. METHODS We recruited patients with first-episode schizophrenia (n = 63) and healthy controls (n = 48), and quantified OFC H-shaped sulci volumes with 3.0 T high-resolution MRI. We assessed cognitive function and childhood trauma experiences using the MATRICS Consensus Cognitive Battery (MCCB) and the Childhood Trauma Questionnaire (CTQ). RESULTS Patients with first-episode schizophrenia had smaller left OFC H-shaped sulci volumes, more severe childhood trauma experiences and worse cognitive function than healthy controls. CTQ total score and emotional and physical neglect subscores were negatively correlated with left OFC H-shaped sulci volume. CTQ total score and emotional neglect and sexual abuse subscores were negatively correlated with cognitive function in patients with first-episode schizophrenia. Interestingly, the CTQ total score and physical neglect subscore were positively correlated with cognitive function in healthy controls. Left OFC H-shaped sulci volume played a mediating role in CTQ emotional neglect subscore, CTQ total score and MCCB composite score. LIMITATIONS The small sample size and retrospective design need to be considered. CONCLUSION Childhood trauma might contribute to cognitive deficits in patients with first-episode schizophrenia by affecting left OFC H-shaped sulci volume. This finding can help in the design of strategies to improve cognitive function in patients with first-episode schizophrenia.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Yunlong Tan
- From the Peking University Huilongguan Clinical Medical School, Beijing Huilongguan Hospital, Beijing, P. R. China (L. Wang, Yin, Feng, Zhou, Huang, Zhang, Chen, Fan, S. Tan, Z. Wang, B. Tian, Y. Tan); the Department of Pharmacy, Peking University First Hospital, Beijing, P.R. China (Cui); the Department of Psychiatry, Yale University School of Medicine, New Haven, CT (Luo, Li); the Institute of Biomedicine and Translational Medicine, Department of Physiology, Faculty of Medicine, University of Tartu, Tartu, Estonia (L. Tian)
| |
Collapse
|
8
|
Ka-Yi Chat I, Gepty AA, Kautz M, Giollabhui NM, Adogli ZV, Coe CL, Abramson LY, Olino TM, Alloy LB. Residence in High-Crime Neighborhoods Moderates the Association between Interleukin-6 and Social and Non-Social Reward Brain Responses. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2022; 2:273-282. [PMID: 35873737 PMCID: PMC9306340 DOI: 10.1016/j.bpsgos.2022.04.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Background Residence in high-crime neighborhoods, especially in childhood, is linked to mental health issues later. Detecting distinct neurobiological processes underlying the effects of this environmental stressor may be critical to identifying prevention and intervention targets. This study examined the relationships of levels of a circulating inflammatory protein with social and monetary reward–related brain function among adolescents who lived in high- versus low-crime neighborhoods during childhood. Methods A total of 70 participants (mean age = 16.3 years; 57% female) completed measures of inflammatory markers, depression history, and health and 2 functional magnetic resonance imaging tasks assessing responsivity to monetary and social rewards. Multivariate linear regression tested whether individuals with higher interleukin 6, an inflammatory cytokine, who also lived in neighborhoods with higher crime had distinct orbitofrontal cortex and nucleus accumbens activation to monetary reward and social acceptance. Results For adolescents who lived in neighborhoods with more crime, higher interleukin 6 was associated with higher nucleus accumbens responses to social acceptance. We did not detect significant moderating effects of neighborhood crime rates on the associations of interleukin 6 with orbitofrontal cortex responses to social acceptance or orbitofrontal cortex/nucleus accumbens activation during monetary reward anticipation or outcome. These results were obtained before and after adjusting for neighborhood income and other covariates. We did not detect significant moderating effects of neighborhood income. Conclusions High-threat residence environment and specific demands of the social context in childhood may have shaped the effect of peripheral immune activation on reward-related neural function in adolescence. The prevailing view that inflammation-associated behaviors are characterized by blunted responsiveness to reward may be oversimplistic.
Collapse
|
9
|
Moriarity DP, Ellman LM, Coe CL, Olino TM, Alloy LB. A physiometric investigation of inflammatory composites: Comparison of "a priori" aggregates, empirically-identified factors, and individual proteins. Brain Behav Immun Health 2021; 18:100391. [PMID: 34877552 PMCID: PMC8628205 DOI: 10.1016/j.bbih.2021.100391] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 11/15/2021] [Indexed: 01/03/2023] Open
Abstract
Most research testing the association between inflammation and health outcomes (e.g., heart disease, diabetes, depression) has focused on individual proteins; however, some studies have used summed composites of inflammatory markers without first investigating dimensionality. Using two different samples (MIDUS-2: N = 1255 adults, MIDUS-R: N = 863 adults), this study investigates the dimensionality of eight inflammatory proteins (C-reactive protein (CRP), interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor-α (TNF-α), fibrinogen, E-selectin, and intercellular adhesion molecule (ICAM)-1) and compared the resulting factor structure to a) an "a priori"/tau-equivalent factor structure in which all inflammatory proteins equally load onto a single dimension (comparable to the summed composites) and b) proteins modeled individually (i.e., no latent variable) in terms of model fit, replicability, reliability, and their associations with health outcomes. An exploratory factor analysis indicated a two-factor structure (Factor 1: CRP and fibrinogen; Factor 2: IL-8 and IL-10) in MIDUS-2 and was replicated in MIDUS-R. Results did not clearly indicate whether the empirically-identified factor structure or the individual proteins modeled without a latent variable had superior model fit, but both strongly outperformed the "a priori"/tau-equivalent structure (which did not achieve acceptable model fit in any models). Modeling the empirically-identified factors and individual proteins (without a latent factor) as outcomes of medical diagnoses resulted in comparable conclusions. However, modeling individual proteins resulted in findings more robust to correction for multiple comparisons despite more conservative adjustments. Further, reliability for all latent variables was poor. These results indicate that modeling inflammation as a unidimensional construct equally associated with all available proteins does not fit the data well. Instead, individual inflammatory proteins or, potentially (if empirically supported and biologically-plausible) empirically-identified inflammatory factors should be used in accordance with theory.
Collapse
Affiliation(s)
- Daniel P. Moriarity
- Temple University, USA
- McLean Hospital, Harvard Medical School
- Corresponding author. Department of Psychology, Temple University, Weiss Hall, 1701 N. 13th St., Philadelphia, PA 19122, USA.
| | | | | | | | | |
Collapse
|
10
|
Moriarity DP. Building a replicable and clinically-impactful immunopsychiatry: Methods, phenotyping, and theory integration. Brain Behav Immun Health 2021; 16:100288. [PMID: 34589785 PMCID: PMC8474613 DOI: 10.1016/j.bbih.2021.100288] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 06/21/2021] [Accepted: 06/22/2021] [Indexed: 10/25/2022] Open
Abstract
Immunopsychiatry is a subfield of psychoneuroimmunology that integrates immunological and psychopathological processes with promise for improving the classification, identification, and treatment of psychopathology. Using research on the relationship between inflammation and depression as a running example, this mini-review will discuss three areas of work that should be emphasized in future research to maximize the replicability and clinical impact of the field: 1) methodology with respect to planning data collection and statistical analyses with measurement properties and conceptually important sources of variance in mind, 2) characterizing inflammatory phenotypes of psychopathology, and 3) the integration of inflammatory processes into robust, extant psychosocial theoretical frameworks of psychopathology risk. Consistent, parallel growth in all three areas will ensure immunopsychiatry research is replicable, contributes to understanding of how (and for whom) the immune system is associated with psychiatric symptoms, and increases the flexibility and power of personalized treatment planning.
Collapse
Affiliation(s)
- Daniel P Moriarity
- Department of Psychology, Temple University, Weiss Hall, 1701 N. 13th St., Philadelphia, PA, 19122, USA
| |
Collapse
|