The neuroanatomy of social trust predicts depression vulnerability

Abstract

Trust attitude is a social personality trait linked with the estimation of others' trustworthiness. Trusting others, however, can have substantial negative effects on mental health, such as the development of depression. Despite significant progress in understanding the neurobiology of trust, whether the neuroanatomy of trust is linked with depression vulnerability remains unknown. To investigate a link between the neuroanatomy of trust and depression vulnerability, we assessed trust and depressive symptoms and employed neuroimaging to acquire brain structure data of healthy participants. A high depressive symptom score was used as an indicator of depression vulnerability. The neuroanatomical results observed with the healthy sample were validated in a sample of clinically diagnosed depressive patients. We found significantly higher depressive symptoms among low trusters than among high trusters. Neuroanatomically, low trusters and depressive patients showed similar volume reduction in brain regions implicated in social cognition, including the dorsolateral prefrontal cortex (DLPFC), dorsomedial PFC, posterior cingulate, precuneus, and angular gyrus. Furthermore, the reduced volume of the DLPFC and precuneus mediated the relationship between trust and depressive symptoms. These findings contribute to understanding social- and neural-markers of depression vulnerability and may inform the development of social interventions to prevent pathological depression.

Figure 1

Trust and depressive symptoms. (A) Significant negative correlation between trust (TA1) and depressive symptoms measured up to 17 months apart. (B) Significant higher depressive symptoms in low trusters relative to middle and high trusters. The three groups were created based on their trust scores (TA1). (C) The distribution of depressive symptoms among low trusters was significantly skewed toward higher values relative to middle and high trusters.

Figure 2

Reduced volume of social brain regions among low trusters. Social brain regions positively associated with trust (Table 1) also showed robust group differences when participants were classified as low trusters, middle trusters and high trusters. Population marginal means and error bars (standard error) were calculated with ANCOVA and all P-values are Bonferroni corrected for multiple comparisons. Gray matter volume is adjusted for age, sex, education, income and TIV.

Figure 3

Whole-brain VBM analyses of trust and depressive symptoms. (A) Social brain regions with increased gray matter volume in high trusters relative to low trusters. Highlighted brain regions include the MFG, DMPFC, precuneus, posterior cingulate and angular gyrus. (B) Enlargement of social brain regions in healthy controls relative to MDD patients in the Hiroshima sample. Both analyses were performed using a non-parametric permutation method and a statistical threshold of P_FWE < 0.05, family-wise error corrected for the whole-brain.

Figure 4

Mediation role of social brain regions on the link between trust and future depressive symptoms. Mediation analysis revealed significant indirect effects of GM volume of the left DLPFC (A) and left precuneus (B) on the relationship between trust and future depressive symptoms.