Inflammation and Social Avoidance
Creators: name: Madison, Annelise
name: Kiecolt-Glaser, Janice
name: Ratner, Kyle
name: Way, Baldwin
name: Andridge, Rebecca
Publisher: name: Open Science Framework
Year: 2022
Subjects: subject: Social and Behavioral Sciences

description: Prior translational research has demonstrated that inflammation can hamper social behavior. LPS-injected adult male rats avoid juvenile males (R. Bluthe et al., 1994; R.-M. Bluthe et al., 1992; Marvel et al., 2004). In humans, LPS-injected adults reported feeling more socially disconnected (Eisenberger et al., 2010; Moieni et al., 2015) and have less desire to be social (Hannestad et al., 2011), and women may be especially prone to inflammation’s social effect (Moieni et al., 2015). Moreover, these observed differences in self-reported feelings correspond with neuroimaging findings (e.g., those exposed to endotoxin have greater amygdala responses to socially threatening images; Inagaki et al., 2012). Moreover, familiarity and affinity may play a role in avoidance, such that those with heightened inflammation may approach loved ones while avoiding more distant others (Eisenberger et al., 2017). Inflammation’s effect on social processes is especially relevant to mental health, as heightened inflammation is an etiological and maintenance factor in a subset of depression cases, and social withdrawal is a characteristic of depression. Experimental paradigms have primarily utilized LPS, which is a potent stimulus that powerfully triggers sickness symptoms (e.g., malaise, nausea, fever, fatigue). Although past studies have statistically adjusted for sickness symptoms, doing so does not completely isolate a co-occurring process. In this paradigm, we will use a less potent but biologically-relevant and reliable inflammatory stimulus – a typhoid vaccine. We will attempt to replicate prior findings of reduced self-reported feelings of social connection following this less potent inflammatory stimulus. Then, for the first time in humans, we will test inflammation’s effect on implicit and explicit social avoidance via a task that uses a variety of emotional facial stimuli. At two separate visits, female breast cancer survivors received a typhoid vaccine and placebo in a random order. Immediately after the injection, they completed the Social Connection Scale and Center for Epidemiological Studies Depression Scale (CES-D). Seven hours after the injection, they engaged in the 15-minute computer-based implicit social withdrawal task, followed immediately by the five-minute computer based explicit social withdrawal task. Eight hours after the injection, they completed a second administration of the Social Connection Scale. We will test the effect of (1) basal inflammation; (2) the vaccine; (3) the vaccine-induced inflammatory response on self-reported social connection as well as performance on the implicit and explicit social withdrawal task. This study aims to decipher between three plausible hypotheses: (1) Inflammation-induced fatigue fuels avoidance of all facial stimuli, regardless of emotion; (2) Inflammation provokes avoidance of only threatening faces (e.g., anger); (3) Inflammation dampens approach behavior toward happy faces. In secondary analyses, we will examine whether depressive symptoms heighten observed inflammation-related social avoidance.