From childhood maltreatment to adult inflammation: Evidence for the mediational status of social anxiety and low positive affect

Perceived Control and Inflammation: Mediating and Moderating Effects in the Relationship Between Cumulative Trauma and Depression

OBJECTIVE

The effects of trauma exposure on depression risk and severity are well established, but psychosocial and biological factors that impact or explain those relationships remain poorly understood. This study examined the moderating and mediating effects of perceived control and inflammation in the relationship between trauma and depression.

METHODS

Moderation analyses and longitudinal mediation analyses were conducted on data from 945 adults who completed all three waves (spanning around 19 years) of the Midlife Development in the United States (MIDUS) study and the MIDUS Biomarker Study. Data were collected during a phone interview, self-report surveys distributed in the mail, and an in-person blood draw. Two dimensions of perceived control-mastery and constraints-were examined separately in all analyses.

RESULTS

Perceived control did not significantly moderate the relationship between trauma and depression severity at MIDUS 2 ( b = 0.03, SE = .02, p = .091). Constraints significantly mediated the relationship between trauma and MIDUS 3 depression (indirect effect = 0.03, SE = 0.01, p = .016) but not after accounting for MIDUS 2 depression. Perceived control did not have a significant moderating effect in the relationships between trauma and inflammation or inflammation and depression.

CONCLUSIONS

Findings from this study revealed that perceived control may be better characterized as an explanatory factor rather than a buffer in trauma-associated depression. Perceived constraints in particular may be a useful treatment target for trauma-associated depression. Further research is needed to examine whether these results generalize to populations other than among mostly non-Hispanic White adults in the United States.

Paternal deprivation induces vigilance-avoidant behavior and accompanies sex-specific alterations in stress reactivity and central proinflammatory cytokine response in California mice (Peromyscus californicus)

RATIONALE

Early-life stress (ELS) can increase anxiety, reduce prosocial behaviors, and impair brain regions that facilitate emotional and social development. This knowledge greatly stems from assessing disrupted mother-child relationships, while studies investigating the long-term effects of father-child relationships on behavioral development in children are scarce. However, available evidence suggests that fathers may uniquely influence a child's behavioral development in a sex-specific manner. Rodent models examining mother-offspring interaction demonstrate relationships among ELS, neuroinflammatory mediators, and behavioral development; yet, the role paternal care may play in neuroimmune functioning remains unreported.

OBJECTIVES

Using the biparental California mouse (Peromyscus californicus), we examined to what extent paternal deprivation impairs social and anxiety-like behaviors, augments peripheral corticosterone (CORT) response, and alters central proinflammatory cytokine production following an acute stressor in adulthood.

METHODS

Biparentally reared and paternally deprived (permanent removal of the sire 24 h post-birth) adult mice were assessed for sociability, preference for social novelty, social vigilance, and social avoidance behaviors, followed by novelty-suppressed feeding (NSF) testing for general anxiety-like behavior. Following an acute stressor, circulating CORT concentrations and region-specific proinflammatory cytokine concentrations were determined via radioimmunoassay and Luminex multianalyte analysis, respectively.

RESULTS

In response to a novel same-sex conspecific, social vigilance behavior was associated with reduced sociability and increased avoidance in paternally deprived mice-an effect not observed in biparentally reared counterparts. Yet, in response to a familiar same-sex conspecific, social vigilance persisted but only in paternally deprived females. The latency to consume during NSF testing was not significantly altered by paternal deprivation. In response to an acute physical stressor, lower circulating CORT concentrations were observed in paternally deprived females. Compared to control-reared males, paternal deprivation increased hypothalamic interleukin-1β, but decreased hippocampal IL-6 protein concentration.

CONCLUSION

Greater social vigilance behavior was demonstrated in paternally deprived mice while they avoided social interaction with a novel same-sex conspecific; however, in response to a familiar same-sex conspecific, paternal deprivation increased social vigilance behavior but only in females. It is possible that different neurobiological mechanisms underlie these observed behavioral outcomes as sex-specific central proinflammatory cytokine and stress responsivity were observed in paternally deprived offspring.

Associations between resting-state neural connectivity and positive affect in social anxiety disorder

INTRODUCTION

Social anxiety disorder (SAD) has been characterized by deficits in social motivation and lack of reactivity to pleasurable stimuli (i.e., positive affect; [PA]). Recent neuroimaging work has shifted toward examining positively valenced motivational systems in SAD focused on reward responses. However, little is known about the associations of reward connectivity and PA in individuals with SAD. As such, the purpose of the current study was to determine whether connectivity among key units of reward neurocircuitry meaningfully relate to PA and whether these key units are more heterogeneous in SAD as compared to controls.

METHODS

Thirty-one participants who met diagnostic criteria for SAD and 33 control participants were included (Mage = 24.8, SD = 6.9; 55% cisgender man). Seed-based timeseries correlations were conducted in NiTime to extract region of interest (ROI) coupling correlation strength values. ANOVAs were carried out to assess whether individuals with SAD differed in ROI-to-ROI connectivity strength as compared to controls. Correlations and variance analyses were also conducted to examine the relationship between ROI-to-ROI connectivity strength and PA, as well as heterogeneity in connectivity strength and PA expression.

RESULTS

Weaker connectivity between the left and right orbital frontal cortex was observed when comparing the SAD to the control group. Within the SAD group, PA was associated with several reward-related ROI couplings; however, these links were not observed among controls. Results further demonstrated that individuals with SAD had significantly more variability in reward connectivity strength as compared to controls.

CONCLUSION

Overall, these results provide emergent evidence for the association between reward regions and PA in individuals with SAD. Additionally, these findings show that individuals with SAD demonstrate greater heterogeneity in reward connectivity.

Validation of a novel method of ultraviolet-induced cutaneous inflammation and its associations with anhedonia

Affective immunology of the skin is a growing area; however, established protocols for measuring individual differences in cutaneous inflammation are lacking. To address this, we present a preliminary validation of Precision Implementation of Minimal Erythema Dose (PI-MED) testing as a method for measuring cutaneous inflammation. PI-MED is a recently adapted protocol, optimized for reproducibility and individual differences research, that uses ultraviolet (UV) light to evoke cutaneous erythema, or inflammatory skin reddening. PI-MED's novel UV dosage schedule produces standardized erythema responses across different skin pigmentation types and shows strong internal consistency within person and good test-retest reliability across 8-10 weeks. In line with predictions, increased PI-MED erythema was associated with heightened anhedonia, across several measures, beyond influences of non-affective covariates. While future work should further refine the dosage schedule for the lightest and darkest skin types, overall, evidence supports PI-MED as a protocol for inducing and measuring individual differences in cutaneous inflammation. Further, PI-MED-induced erythema can expand psychoneuroimmunology research by offering a complementary assessment for general inflammatory tone. This work adds to a growing body of evidence demonstrating a distinct relationship between inflammation and anhedonia.