Social approach-avoidance conflict: Behavioural, emotional, and neural correlates along a depression-social anxiety spectrum.

Approach-avoidance conflict, in which the same option entails both rewarding and aversive consequences, has been proposed as a key process in internalizing disorders such as depression and social anxiety. Yet, human paradigms that model approach-avoidance conflict and link it to brain function remain scarce. In particular, it has been emphasized the need for studying this conflict in social contexts. We developed a Social Approach-Avoidance Conflict (SAAC) task that involved a social evaluative demand manipulation, and combined it with functional magnetic resonance imaging (fMRI) in 135 young adults. On each trial, participants decided whether to accept a variable reward at the cost of increasing the presence of more or less demanding judges in a future public speaking evaluation, or to avoid and receive a minimal default reward. Depression and social anxiety (D-SA) symptoms were summarized into a single continuous dimension derived from principal component analysis of psychological questionnaires. Behaviourally, higher payments increased approach, whereas higher judge ranks increased negative affect and avoidance. Higher D-SA scores were associated with reduced positive and heightened negative emotional responses to higher-rank judges, stronger preferences for low-rank judges, and greater avoidance of high-rank judges. Neurally, increasing judge rank recruited the dmPFC/dACC during approach decisions, and higher D-SA symptoms were associated with stronger responses in these regions. Increasing payment during approach engaged dmPFC/vmPFC, PCC, and posterior insula, and these reward-related responses were attenuated at higher D-SA levels. In conclusion, internalizing symptoms of depression and social anxiety are associated with a bias in emotional and behavioural responses when a reward competes with a social evaluative threat. At the neural level, internalizing symptoms were associated with an enhanced aversive/conflict signalling in the dmPFC/dACC, and with reduced reward-related activity. Findings shed light on the mechanisms underlying costly social avoidance in internalizing disorders.