Loneliness and cortisol are associated with social network regulation

The relationship of coping style and social support variation to glucocorticoid metabolites in wild olive baboons (Papio anubis)

Social support, via investment in relationships of importance with others, is often emphasized as a pathway towards mediating stress. The effectiveness of social support, however, can be altered by personality differences, but the physiological consequences of such covariation are still poorly explored. How do individual differences in the functioning of the stress response system mediate access to, and use of, social support? To examine this dynamic, we investigated glucocorticoids as a biomarker of energetic activation that may also be activated by chronic psychosocial stress. For this purpose, we studied a wild anthropoid primate, i.e. the olive baboon (Papio anubis), for 17 months, in Laikipia District, Kenya. We measured biomarkers of energetic activation, i.e., fecal glucocorticoid metabolites (fGCms), to address whether individual differences in stress coping and social support were associated with variation in hormone levels across a period from 2018 to 2019. We found evidence for an association between social support and fGCm concentrations. This association had a discernable interaction between sex and social support: we found a negative association in male baboons, relative to females-who did not have a pronounced effect. Our findings emphasize the importance of social support in male baboons. The cost of not having diverse bonds, has been downplayed in male baboons.

Loneliness and socioemotional memory

Do chronically high-lonely individuals exhibit specific memory biases when recalling past social episodes? We explored negative memory biases, focusing on the recall of unfavourable social experiences and social memory biases, emphasizing the recall of social experiences irrespective of emotional valence. We conducted a dictionary-based semantic analysis of autobiographical episodes obtained from 4095 participants via four datasets. Participants recalled a positive, negative or emotionally neutral episode from their recent past. High-lonely individuals predominantly exhibited a decline in recalling positive social episodes, providing partial support for negative memory biases. However, both high- and low-lonely individuals were similarly inclined to recall negative social episodes. These results suggest that the primary issue among high-lonely individuals is the limited recall of positive social experiences rather than the general negativity in memory biases or the hypersensitivity to general social memories.

Korean Red Ginseng and Rb1 restore altered social interaction, gene expressions in the medial prefrontal cortex, and gut metabolites under post-weaning social isolation in mice

Background

Post-weaning social isolation (SI) reduces sociability, gene expressions including myelin genes in the medial prefrontal cortex (mPFC), and alters microbiome compositions in rodent models. Korean Red Ginseng (KRG) and its major ginsenoside Rb1 have been reported to affect myelin formation and gut metabolites. However, their effects under post-weaning SI have not been investigated. This study investigated the effects of KRG and Rb1 on sociability, gene expressions in the mPFC, and gut metabolites under post-weaning SI.

Methods

C57BL/6J mice were administered with water or KRG (150, 400 mg/kg) or Rb1 (0.1 mg/kg) under SI or regular environment (RE) for 2 weeks during the post-weaning period (P21-P35). After this period, mice underwent a sociability test, and then brains and ceca were collected for qPCR/immunohistochemistry and non-targeted metabolomics, respectively.

Results

SI reduced sociability compared to RE; however, KRG (400 mg/kg) and Rb1 significantly restored sociability under SI. In the mPFC, expressions of genes related to myelin, neurotransmitter, and oxidative stress were significantly reduced in mice under SI compared to RE conditions. Under SI, KRG and Rb1 recovered the altered expressions of several genes in the mPFC. In gut metabolomics, 313 metabolites were identified as significant among 3027 detected metabolites. Among the significantly changed metabolites in SI, some were recovered by KRG or Rb1, including metabolites related to stress axis, inflammation, and DNA damage.

Conclusion

Altered sociability, gene expression levels in the mPFC, and gut metabolites induced by two weeks of post-weaning SI were at least partially recovered by KRG and Rb1.

The loneliness factor in eating disorders: Implications for psychopathology and biological signatures

OBJECTIVES

Eating disorders (ED) are severe psychiatric conditions. While the biological consequences of EDs are well established, including an increase in inflammatory biomarkers, the influence of psychological factors, such as loneliness, has only recently gained attention in research. Loneliness has been associated with more severe psychopathology in ED patients, while its association with inflammatory biomarkers has only been explored in the general population. For these reasons, we aimed to investigate any possible associations between psychological features, trauma, and inflammatory biomarkers with loneliness in people with ED.

METHODS

This study examined the interaction between loneliness, eating psychopathology, and biological markers in people with EDs. A group of 97 female patients with various diagnoses of ED was assessed for loneliness, general and eating psychopathology, traumatic history during childhood, and clinical biomarkers such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and urinary-free cortisol (UFC).

RESULTS

The results indicated that individuals with ED who reported moderate to severe loneliness also displayed greater general psychopathology (p = 0.001), weight concerns (p = 0.007), and physical neglect during childhood (p = 0.006). Furthermore, people with higher levels of loneliness also had higher inflammatory indexes (ESR p = 0.001, CRP p = 0.027) and were positively correlated with markers of stress reaction such as UFC (p < 0.05).

CONCLUSION

The findings underscore the importance of considering loneliness in the assessment of individuals with an ED. We observed notable associations between loneliness and increased psychopathology (both general and specific to eating), as well as higher levels of inflammation and childhood physical neglect. Addressing loneliness may contribute to improving overall well-being and potentially support recovery. This consideration encompasses both psychological and physical factors that interplay in the clinical presentation of individuals.

Psychosocial health modifies associations between HPA-axis function and brain structure in older age

BACKGROUND

Dysregulation of the negative feedback loop of the hypothalamic-pituitary-adrenal (HPA) axis may have damaging effects on the brain, potentially under influence of psychosocial health factors. We studied associations between functioning of the negative feedback loop of HPA-axis, measured with a very low-dose dexamethasone suppression test (DST), and brain structure in middle-aged and older adults, and whether these associations were modified by psychosocial health.

METHODS

From 2006 to 2008, 1259 participants (mean age 57.6 ± 6.4, 59.6 % female) of the population-based Rotterdam Study completed a very low-dose DST (0.25 mg) and underwent magnetic resonance imaging (MRI) of the brain. Self-reported psychosocial health (depressive symptoms, loneliness, marital status, perceived social support) were assessed in the same time period. Multivariable linear and logistic regression were used to study cross-sectional associations between cortisol response and brain volumetrics, cerebral small vessel disease markers and white matter structural integrity. To assess the effect of psychosocial health on these associations, analyses were further stratified for psychosocial health markers.

RESULTS

Cortisol response was not associated with markers of global brain structure in the overall study sample. However, in participants with clinically relevant depressive symptoms, a diminished cortisol response was associated with smaller white matter volume (mean difference: - 1.00 mL, 95 %CI = - 1.89;- 0.10) and smaller white matter hyperintensity volume (mean difference: - 0.03 mL (log), 95 %CI = - 0.05;0.00). In participants with low/moderate perceived social support compared to those with high social support, a diminished cortisol response was associated with larger gray matter volume (mean difference: 0.70 mL, 95 %CI = 0.01;1.39) and higher fractional anisotropy (standardized mean difference 0.03, 95 %CI = 0.00;0.06).

CONCLUSION

Diminished function of the HPA-axis is differently associated with brain structure in community-dwelling middle-aged and older adults with clinically relevant depressive symptoms or suboptimal social support, but not in adults without depressive symptoms or with optimal social support.

The association between autistic traits and excessive smartphone use in Chinese college students: The chain mediating roles of social interaction anxiety and loneliness

This study draws upon a large sample of Chinese college students to examine the chain mediating roles of social interaction anxiety and loneliness in the relation between autistic traits and excessive smartphone use. To test our hypothesis that social interaction anxiety and loneliness mediate the relation between autistic traits and excessive smartphone use, we recruited a sample of 1103 college students and asked them to complete an assessment that measured the degrees of autistic traits, social interaction anxiety, loneliness, and excessive smartphone use. The results showed significant correlations among these variables. More autistic traits, which are correlated with higher levels of social interaction anxiety and higher levels of loneliness, were found to be associated with excessive smartphone use. In conclusion, this study highlights the need for screening for excessive smartphone use among college students who demonstrate autistic traits. Social interaction anxiety and loneliness show great potential in screening for excessive smartphone use among college students with high levels of autistic traits. We discuss the practical implications of the findings and directions for future study.

Preliminary insights into associations between C-reactive protein and social network dynamics

Recent social psychoneuroimmunology models suggest bidirectional associations between social experiences and the immune system. This work posits that social relationships and networks may influence the functioning of the immune system, but we know little about the role that the immune system plays in how social networks are created and maintained. We examine how salivary C-reactive protein (CRP), as an inflammatory protein, is associated with making new and keeping existing friendship and conflicted relationships among young adult members of a social group. Participants (n = 37; 67.6% female; M age = 18.18 years, 56.81% white/non-Hispanic) provided nominations of friends and individuals with whom they have conflict at wave 1 and two months later at wave 2. At wave 1, in a group setting, participants donated saliva, later assayed for CRP. Stochastic actor-based models revealed that CRP levels were negatively associated with keeping existing friends and positively associated with developing new friendships. We also found that CRP levels were negatively associated with creating new conflicted relationships and predicted an increased likelihood that group members continue conflicted relationships with the focal individual. These preliminary results support the premises of recent social psychoneuroimmunology models by suggesting that inflammation can also serve as a signal to seek new supportive relationships such as friendships and avoid creating new relationships characterized by threat and/or conflict. Findings provide new insights into the theorized function of the immune system for social approach and withdrawal patterns through which our social connections are constructed.