The mediating role of social anxiety in the association between personality traits and Internet addiction and its underlying neural basis.

Social anxiety (SA) is one of the most prevalent mental health problems in young adults. The significance of personality traits on the development of SA and the influence of SA on Internet addiction (IA) were increasingly emphasized. However, no studies yet have simultaneously examined the relationships among SA, personality traits, and IA, especially the role of SA and its underlying neural basis in the association between personality traits and IA. Therefore, this study was designed to address this question using behavioral and resting-state functional Magnetic Resonance Imaging (fMRI) measurements in a non-clinical sample of Chinese college students. Behavioral results indicated significant intercorrelations between Big Five personality traits, SA, and IA, with SA mediating the relationship between four personality traits (i.e., neuroticism, extraversion, openness, and conscientiousness) and IA. fMRI results showed that SA was negatively correlated with precuneus-occipital connectivity, which is associated with emotional face processing and self-focused attention. More importantly, the precuneus-occipital connectivity and SA played a chain mediating role in the association between the two personality traits (i.e., extraversion and openness) and IA. Together, these findings advanced our understanding of the psychological and neurobiological underpinnings of SA, especially its pivotal role in the relation between personality traits and IA.