Reward Responsiveness and Ruminative Styles Interact to Predict Inflammation and Mood Symptomatology

Orbital frontal cortex functional connectivity during gain anticipation linking the rumination and non-suicidal self-injury in late adolescence

OBJECTIVE

Non-suicidal self-injury (NSSI) is prevalent and especially among the adolescence population. It has been argued that abnormal brain activations in reward processing could be regarded as objective biomarkers in NSSI, but the evidence is mixed. This study aims to explore the reward processing mechanism of NSSI from the perspective of functional brain circuitry and investigate the role of a cognitive factor (rumination).

METHOD

Seventy-one 17-21 years old participants performed a monetary incentive delay (MID) task during functional magnetic resonance imaging scanning. Psychophysiological interaction (PPI) analysis was used to test the inner-group differences of brain functional connectivity. In addition, a mediation model was established with the mediation effect of rumination on the relationship between functional brain circuitry and NSSI.

RESULTS

PPI analysis suggested that functional connectivity of the orbital frontal cortex (OFC) (with precuneus, SMA) was significantly enhanced in NSSI in the gain > loss contrast, but not in the loss > gain contrast. Mediation analysis revealed that rumination mediated the relationship between NSSI and the OFC- precuneus functional connectivity in the gain > loss contrast.

CONCLUSION

Our research revealed that the abnormal OFC functional connectivity in gain (not loss) anticipation can be served as the sensitive biomarkers of NSSI. And there was a chain path for NSSI, that was from functional brain circuitry to negative cognition and then to problem behavior.

A systematic review of associations between emotion regulation characteristics and inflammation

Elevated inflammation is a risk factor for many psychiatric (e.g., depression) and somatic conditions (e.g., rheumatoid arthritis). Inflammation is influenced by psychosocial processes such as emotion regulation. Characterization of which emotion regulation characteristics impact inflammation could help refine psychosocial interventions aimed at normalizing health-harming inflammatory activity for individuals with psychiatric and somatic illnesses. To investigate this issue, we systematically reviewed the literature on associations between a variety of emotion regulation traits and inflammation. Out of 2816 articles identified, 38 were included in the final review. 28 (74%) found that (a) poor emotion regulation is associated with higher inflammation and/or (b) strong emotion regulation skills are associated with lower inflammation. Consistency of results differed as a function of the emotion regulation construct investigated and methodological characteristics. Results were most consistent for studies testing positive coping/social support seeking or broadly defined emotion regulation/dysregulation. Methodologically, studies testing reactivity to a stressor, adopting a vulnerability-stress framework, or using longitudinal data were most consistent. Implications for integrated, transdiagnostic psychoimmunological theories are discussed, as well as recommendations for clinical research.

Splitting the reward: Differences in inflammatory marker associations with neural connectivity between reward anticipation and reward outcome in adolescents at high risk for depression

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.

Mood Symptom Dimensions and Developmental Differences in Neurocognition in Adolescence

Adolescence is critical period of neurocognitive development as well as increased prevalence of mood pathology. This cross-sectional study replicated developmental patterns of neurocognition and tested whether mood symptoms moderated developmental effects. Participants were 419 adolescents (n=246 with current mood disorders) who completed reward learning and executive functioning tasks, and reported on age, puberty, and mood symptoms. Structural equation modeling revealed a quadratic relationship between puberty and reward learning performance that was moderated by symptom severity: in early puberty, adolescents reporting higher manic symptoms exhibited heightened reward learning performance (better maximizing of rewards on learning tasks), whereas adolescents reporting elevated anhedonia showed blunted reward learning performance. Models also showed a linear relationship between age and executive functioning that was moderated by manic symptoms: adolescents reporting higher mania showed poorer executive functioning at older ages. Findings suggest neurocognitive development is altered in adolescents with mood pathology and suggest directions for longitudinal studies.

Protocol for project MIME: Motivation, inflammation, and Mood in Emerging Adults

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.

Residence in High-Crime Neighborhoods Moderates the Association between Interleukin-6 and Social and Non-Social Reward Brain Responses

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.

Depressive symptoms and other negative psychological states relate to ex vivo inflammatory responses differently for men and women: Cross-sectional and longitudinal evidence

An array of negative psychological states - including depressive symptoms, perceived stress, rumination, and negative affect - have been linked to immune function and inflammatory responses. Herein we show evidence of gender-dependent associations between ex vivo lipopolysaccharide (LPS)-stimulated cytokine responses and such psychological states, in both cross-sectional and longitudinal analyses from three annual waves (N = 162 at baseline, 67.3% female). In cross-sectional analyses (at baseline), gender moderated the associations of depressive symptoms (previously reported), perceived stress (B = -0.043, 95%CI [-0.080, -0.015]), rumination (B = -0.500, [-1.015, -0.232]), negative affect (B = -0.020, [-0.020, -0.005]), and positive affect (B = 0.024, [0.008, 0.047]) with LPS-stimulated cytokine responses. In each analysis, negative psychological states were positively associated with LPS-stimulated cytokine responses among men but negatively among women (with associations for positive affect in the opposite direction). In longitudinal analyses (across three annual measurements), similar associations were seen for depressive symptoms (B = -0.024, [-0.059, -0.004]), perceived stress (B = -0.045, [-0.069, -0.024]), and rumination (B = -0.381, [-0.622, -0.120]). These results indicate that gender is a critical factor in associations between a broad array of negative psychological states and inflammatory responses and identify one pathway by which gender may influence psychosomatic health.

Understanding associations between rumination and inflammation: A scoping review

A growing body of evidence suggests that rumination, or focused attention on mental representations of negative events, may have physiological consequences that adversely affect long term health. We conducted a scoping review on quantitative studies of humans examining associations between rumination and inflammation, which included 13 studies representing 14 samples and 1,102 unique participants. The review included 8 biomarkers measured in plasma, serum and saliva (C reactive protein, and C-C motif chemokine 11, interleukin (IL)- 1β, IL-4, IL-6, IL-8, IL-10 and tumor necrosis factor alpha). More consistent findings of an association between greater rumination and increased inflammation were found in studies that used experimental designs and manipulated rumination. Emerging research suggests rumination may interact with other factors (e.g., socioeconomic status, anxiety) to predict inflammation. This review offers an up to date synthesis of the emerging research focused on rumination and inflammation. The relationship between inflammation and rumination may be contingent on how rumination is conceptualized and measured, as well as the measure of inflammation (i.e., at rest/ in response to stress).

A physiometric investigation of inflammatory composites: Comparison of "a priori" aggregates, empirically-identified factors, and individual proteins

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.

Inflammation predicts sexual arousability in healthy women

Background

Though many women report sexual arousal difficulties, the mechanisms driving these difficulties are unclear. Sexual response relies on a host of psychophysiological processes that have bidirectional relationships with inflammation. Additionally, chronic inflammation may impair genital blood flow, which in turn may impact sexual arousal. C-reactive protein (CRP) is an acute-phase marker of inflammation produced in response to cytokine signaling throughout the body, which makes it a useful marker of systemic inflammation.

Aim

The present study examined interactions between inflammation and women's sexual arousal.

Methods

CRP, self-reported frequency of partnered sexual activity, and subjective and vaginal arousal were assessed in 91 healthy, pre-menopausal women. Data were collected during a single laboratory session.

Main outcome measures

Subjective sexual arousal and vaginal pulse amplitude (a measure of vaginal arousal) were the main outcome measures.

Results

Change in subjective sexual arousal in response to a sexual film was unaffected by baseline CRP and sexual frequency. However, there were significant interactions between inflammation and sexual frequency in predicting vaginal arousal during the sexual film. Among women reporting more frequent sexual activity, higher CRP predicted lower magnitude arousal response and longer time to maximum vaginal arousal. Among women reporting less frequent sex, higher CRP predicted shorter time to maximum arousal and greater magnitude of arousal response. Controlling for cortisol strengthened the effects seen for time to maximum vaginal arousal but weakened those observed for percent change.

Conclusions

Among healthy young women, higher CRP may be associated with vaginal arousal, but not subjective sexual arousal. Specifically, our results suggest that higher baseline CRP is associated with lower genital sexual arousal for women who have sex frequently, which is consistent with clinical evidence that elevated inflammation can be detrimental to sexual function.

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Among healthy young women, higher CRP may be associated with vaginal sexual arousal, but not subjective sexual arousal.

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Frequency of sexual activity interacts with CRP levels to contribute to vaginal arousal in healthy women.

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Higher CRP predicted lower genital sexual arousal in women who engage in sexual activity more than once a week.

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However, higher CRP predicted greater genital sexual arousal in women who engage in sexual activity less than once a week.

Building a replicable and clinically-impactful immunopsychiatry: Methods, phenotyping, and theory integration

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.

Goal-striving tendencies moderate the relationship between reward-related brain function and peripheral inflammation

Inflammation is associated with both lower and higher activity in brain regions that process rewarding stimuli. How can both low and high sensitivity to rewards be associated with higher inflammation? We propose that one potential mechanism underlying these apparently conflicting findings pertains to how people pursue goals in their environment. This prediction is based on evidence that both an inability to disengage from unattainable goals and low interest in and pursuit of important life goals are associated with poor health outcomes, including inflammation. Accordingly, this study examined the relationship between reward-related brain function and peripheral inflammation among individuals with different levels of ambitious goal-striving tendencies. Eighty-three participants completed an ambitious goal-striving tendency measure, an fMRI Monetary Incentive Delay task assessing orbitofrontal cortex (OFC) and nucleus accumbens (NAc) activation during reward anticipation and outcome, and a venous blood draw to assess the inflammatory biomarkers interleukin (IL)-6, IL-8, tumor necrosis factor-alpha, and C-reactive protein, from which we computed an inflammation composite score. We observed a reward anticipation by goal-striving interaction on inflammation, such that high OFC and NAc activation to reward anticipation (but not outcome) were associated with more inflammation, among high goal-striving individuals. By contrast, low NAc activation during reward anticipation (but not outcome) was associated with more inflammation, among low goal-striving individuals. The current study provides further evidence that both blunted and elevated reward function can be associated with inflammation. It also highlights the role that goal-striving tendencies may play in moderating the relationship between neural reward anticipation and inflammation.

Back to Basics: The Importance of Measurement Properties in Biological Psychiatry

Biological psychiatry is a major funding priority for organizations that fund mental health research (e.g., National Institutes of Health). Despite this, some have argued that the field has fallen short of its considerable promise to meaningfully impact the classification, diagnosis, and treatment of psychopathology. This may be attributable in part to a paucity of research about key measurement properties ("physiometrics") of biological variables as they are commonly used in biological psychiatry research. Specifically, study designs informed by physiometrics are more likely to be replicable, avoid poor measurement that results in misestimation, and maximize efficiency in terms of time, money, and the number of analyses conducted. This review describes five key physiometric principles (internal consistency, dimensionality, method-specific variance, temporal stability, and temporal specificity), illustrates how lack of understanding about these characteristics imposes meaningful limitations on research, and reviews examples of physiometric studies featuring a variety of popular biological variables to illustrate how this research can be done and substantive conclusions drawn about the variables of interest.

Depression and worry symptoms predict future executive functioning impairment via inflammation

BACKGROUND

Scar models posit that heightened anxiety and depression can increase the risk for subsequent reduced executive function (EF) through increased inflammation across months. However, the majority of past research on this subject used cross-sectional designs. We therefore examined if elevated generalized anxiety disorder (GAD), major depressive disorder (MDD), and panic disorder (PD) symptoms forecasted lower EF after 20 months through heightened inflammation.

METHODS

Community-dwelling adults partook in this study (n = 614; MAGE = 51.80 years, 50% females). Time 1 (T1) symptom severity (Composite International Diagnostic Interview - Short Form), T2 (2 months after T1) inflammation serum levels (C-reactive protein, fibrinogen, interleukin-6), and T3 (20 months after T1) EF (Brief Test of Adult Cognition by Telephone) were assessed. Structural equation mediation modeling was performed.

RESULTS

Greater T1 MDD and GAD (but not PD) severity predicted increased T2 inflammation (Cohen's d = 0.21-1.92). Moreover, heightened T2 inflammation forecasted lower T3 EF (d = -1.98 to -1.87). T2 inflammation explained 25-32% of the negative relations between T1 MDD or GAD and T3 EF. T1 GAD severity predicting T3 EF via T2 inflammation path was stronger among younger (v. older) adults. Direct effects of T1 MDD, GAD, and PD forecasting decreased T3 EF were found (d = -2.02 to -1.92). Results remained when controlling for socio-demographic, physical health, and lifestyle factors.

CONCLUSIONS

Inflammation can function as a mechanism of the T1 MDD or GAD-T3 EF associations. Interventions that successfully treat depression, anxiety, and inflammation-linked disorders may avert EF decrements.

How handling extreme C-reactive protein (CRP) values and regularization influences CRP and depression criteria associations in network analyses

Increasingly, it has been recognized that analysis at the symptom, rather than diagnostic, level will drive progress in the field of immunopsychiatry. Network analysis offers a useful tool in this pursuit with the ability to identify associations between immune markers and individual symptoms, independent of all other variables modeled. However, investigation into how methodological decisions (i.e., including vs. excluding participants with C-reactive protein (CRP) >10 mg/L, regularized vs. nonregularized networks) influence results is necessary to establish best practices for the use of network analysis in immunopsychiatry. In a sample of 3,464 adult participants from the 2015-2016 National Health and Nutrition Examination Survey dataset, this study found consistent support for associations between CRP and fatigue and changes in appetite and some support for additional CRP-criterion associations. Methodologically, results consistently demonstrated that including individuals with CRP >10 mg/L and estimating nonregularized networks provided better estimates of these associations. Thus, we recommend considering the use of nonregularized networks in immunopsychiatry and inclusion of cases with CRP values >10 mg/L when testing the association between CRP and depression criteria, unless contraindicated by the research question being tested. Additionally, results most consistently suggest that CRP is uniquely related to fatigue and changes in appetite, supporting their inclusion in an immunometabolic phenotype of depression. Finally, these associations suggest that fatigue and changes in appetite might be particularly receptive to anti-inflammatory treatments. However, future research with more nuanced measures is necessary to parse out whether appetite increases or decreases drive this association. Further, longitudinal research is an important next step to test how these relationships manifest over time.

Behavioral Inhibition/Activation Systems and Depression Among Females With Substance Use Disorder: The Mediating Role of Intolerance of Uncertainty and Anhedonia

Previous studies have shown that the behavioral inhibition/activation systems (BIS/BAS) have substantial effects on substance use disorder and emotional disorders, and substance use disorder and emotional disorders often occur; in particular, females with substance use disorder are more likely to also have serious emotional disorders including depression than their male counterparts. However, the associations between the BIS/BAS and depression in females with substance use disorder have received little attention. Furthermore, the underlying mechanisms of these relations are largely unknown. The present study examines the mediating roles of intolerance of uncertainty and anhedonia in the associations between the BIS/BAS and depression among females with substance use disorder from the Research Domain Criteria (RDoC) framework. A total of 303 females with substance use disorder from a compulsory substance abuse detention center were tested using a cross-sectional survey involving BIS/BAS Scales, Intolerance of Uncertainty Scale, Snaith-Hamilton Pleasure Scale, and Center for Epidemiologic Studies Depression Scale. The path analysis model revealed that both the BIS and BAS had a direct effect on depression, that the BIS had an indirect effect on depression through intolerance of uncertainty, and that the BAS had an indirect effect on depression via anhedonia. These findings contribute to a more thorough understanding of how the BIS/BAS influence depression among females with substance use disorder and suggest that the utility of targeting these associations in treatments would help reduce depression in females with substance use disorder.

The dual-system theory of bipolar spectrum disorders: A meta-analysis

Bipolar spectrum disorders are characterized by alternating intervals of extreme positive and negative affect. We performed a meta-analysis to test the hypothesis that such disorders would be related to dysregulated reinforcement sensitivity. First, we reviewed 23 studies that reported the correlation between self-report measures of (hypo)manic personality and measures of reinforcement sensitivity. A large relationship was found between (hypo)manic personality and BAS sensitivity (g = .74), but not with BIS sensitivity (g = -.08). This stands in contrast to self-reported depression which has a small, negative relationship with BAS sensitivity and a large positive one with BIS sensitivity (Katz et al., 2020). Next, we reviewed 33 studies that compared reinforcement sensitivity between euthymic, bipolar participants and healthy controls. There, bipolar disorder had a small, positive relationship with BAS sensitivity (g = .20) and a medium, positive relationship with BIS sensitivity (g = .64). These findings support a dualsystem theory of bipolar disorders, wherein BAS sensitivity is more closely related to mania and BIS sensitivity more closely to bipolar depression. Bipolar disorders show diatheses for both states with euthymic participants being BAS- and BIS- hypersensitive. Implications for further theory and research practice are expounded upon in the discussion.

Reward Sensitivity, Cognitive Response Style, and Inflammatory Response to an Acute Stressor in Adolescents

Inflammation is gaining support as a biological mediator between stress and many negative outcomes that have heightened risk during adolescence (e.g., mood disorders). Thus, an important line of inquiry is evaluating whether risk factors for mood psychopathology also are associated with heightened inflammatory responses to stress during this developmental period. Two prominent risk factors that interact to predict mood psychopathology are reward sensitivity and perseverative cognitive response styles, which also have been associated with heightened inflammatory proteins. These factors could influence inflammation by synergistically amplifying stress reactivity. Ninety-nine late adolescents (M_age = 18.3 years, range = 15.6-21.9 years) completed measures of reward sensitivity, cognitive response style, and blood draws before and 60-min after a modified Trier Social Stress Task to determine levels of inflammation. Higher reward drive interacted with more perseverative response style ratios (rumination relative to distraction + problem-solving) to predict larger increases in interleukin-6 (a proinflammatory protein). Follow-up analyses found that reward drive interacted with all three components of the ratio to predict change in interleukin-6. Thus, these results suggest that high reward drive and perseverative cognitive response styles are associated with increased inflammatory response to social stress in adolescents, a potential physiological mechanism linking these risk factors to mood psychopathology during this developmental period.