A substantial literature highlights the critical role of stressful or adverse circumstances in precipitating psychopathology, particularly in relation to individual differences in personality, brain function, and genetic predisposition (Caspi et al., 2010, Caspi et al., 2003, Costello et al., 2002 and Monroe and Simons, 1991). In general, epidemiological studies have reported increased risk for psychopathology, particularly mood and anxiety disorders, in individuals having encountered a variety of adverse or stressful situations including childhood maltreatment, violent crime, divorce, unemployment, and medical illness (Hammen, 2005, Kendler et al., 1999 and Monroe and Simons, 1991). In parallel, human neuroimaging studies have revealed that increased sensitivity of neural circuitries, especially the amygdala, to threat and stress may mediate this risk (Price & Drevets, 2010).
Reactivity of the amygdala to threat-related cues such as emotional faces has been linked to trait anxiety (Fakra et al., 2009), anxiety disorders (Phan, Fitzgerald, Nathan, & Tancer, 2006), and depression (Monk et al., 2008 and Siegle et al., 2002), and therefore represents a well researched biological risk factor for negative psychological outcomes. The link between trait anxiety and amygdala reactivity is particularly robust and seen across many different studies and approaches (Dickie and Armony, 2008, Etkin et al., 2004, Fakra et al., 2009, Haas et al., 2007, Hariri, 2009, Killgore and Yurgelun-Todd, 2005, Most et al., 2006, Ray et al., 2005 and Stein et al., 2007). Thus, this research suggests that variability in anxiety, an individual's behavioral sensitivity to threat and stress, reflects in part both the underlying reactivity of these neural circuitries as well as the risk for psychopathology associated with stress and adversity (Hariri, 2009).
Partly in response to the work emphasizing the harmful psychological effects of negative environments, resiliency research has explored factors that may buffer against negative environments and biological risk leading to positive outcomes even in unfavorable environments (Cohen and Hoberman, 1983, Masten, 2001, Masten and Coatsworth, 1998 and Rutter, 2006). One such buffering factor is social support, which typically reflects people in an individual's life (family, friends, neighbors, community members) that are available in times of need and can provide resources such as emotional support (someone with whom to communicate), companionship (someone with whom to spend time and share activities), and instrumental aid (financial and material resources; Cohen & Wills, 1985). Social support has been shown to buffer the relationship between negative life events and depressive symptomatology (Cohen and Hoberman, 1983 and Cohen et al., 1984), and has been associated broadly with well-being and health, both directly and as a buffer against stressful circumstances (Turner, 1981). Interestingly, perceptions of social support are often more powerful in predicting the buffering effects of this support than objective measures ( Cohen et al., 1984). For example, in a review of the stress and social support literature, Cohen and Wills (1985) concluded that studies assessing perceptions of social support found evidence for the “buffering” effect of social support (social support predicted more positive outcomes only during times of stress), whereas those using more objective measures of social support generally found only a main effect of social support (the support predicted positive outcomes regardless of levels of stress). Thus, individuals’ subjective appraisal of their social support may be particularly important in evaluating the effects of social support as a moderator between biological risk and health related outcomes.
In the current study, we asked if perceived social support, a resource for coping with adversity, moderates the link between amygdala reactivity to threat-related cues and the expression of trait anxiety, a well-established personality risk factor for psychopathology (Kendler et al., 2004 and Lahey, 2009). To do so, we used blood oxygen level-dependent functional MRI (BOLD fMRI) to assess threat-related amygdala reactivity in 103 healthy adults. Social support was measured using the Interpersonal Support Evaluation List, a self-report measure of perceived availability of potential social resources including material aid, as well as individuals with whom one can interact and share experiences (Cohen and Hoberman, 1983 and Cohen and Wills, 1985). Multiple indices of personality, mood, and affect as well as an index of recent negative life experiences were also assessed via self-report to examine the specificity of links between social support, amygdala reactivity, and trait anxiety.
