Neurobehavioral signatures of social avoidance and reinforcement learning - a transdiagnostic approach in anorexia nervosa and social anxiety

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Increasingly, psychiatric disease is conceptualized using transdiagnostic and dimensional approaches (e.g.RDoC). Pinpointing overlap, distinction and dimensional variance in neurobehavioral mechanisms of psychiatric symptoms and diagnostic entities is of utmost importance to ultimately advance clinical translation. Neurobehavioral systems supporting approach and avoidance learning play a particular important role in many psychiatric diseases and have been studied extensively in animal and human studies. They can be assessed elegantly using feedback learning paradigms in a computational modelling approach by relating prediction error responses to brain activation during reinforcement and avoidance contexts. This approach has an enormous potential to offer a parsimonious neurobehavioral description of the characteristics of psychiatric symptoms, in particular for the investigation of overlap across diagnostic entities. Here, we employ such a transdiagnostic approach to identify similarities and differences between Anorexia nervosa (AN) and social anxiety disorder (SAD), as well as the specific dimensional influence of social anxiety symptoms. AN is associated with highly dysfunctional approach and avoidance behaviors, e.g. relentless preoccupation with food and pursuit of thinness, but intense fear of gaining weight and avoidance of eating. Neuroimaging studies suggest hyperactive brains systems for feedback learning in AN (e.g. striatum, insula, and amygdala). Recent evidence and longstanding clinical intuition point towards an important role for social anxiety as a precursor and maintaining factor in AN, however, no respective neuroimaging studies on social aspects of feedback processing in AN exist. On the other hand, ample evidence suggests a specific pattern of disturbed neural processing in social anxiety disorder (SAD), including diminished activation for the anticipation of positive social feedback, but increased activation for negative social outcomes. Several lines of evidence suggest, that the characteristics of social anxiety and hyperactive reward system in AN can be considered trait effects, which may be a precursor to the disease and persist after recovery. We will, for the first time, provide a systematic investigation of approach and avoidance systems in social and non-social contexts and their neural implementation within a unifying framework of computational modelling across psychiatric diagnostic entities (AN and SAD), and in relation to social anxiety symptoms within recovered AN and the typical population. Compatible to the “RDoC” framework, this type of approach may take us closer towards a mechanistic understanding of the symptomatology of AN and SAD and may ultimately guide the development of more individualized treatment options and identification of risk-profiles based on neurobehavioral phenotypes of psychiatric symptom clusters and disease.