A transdiagnostic approach to understanding neural responsivity to reward and its links to social motivation.

Schizophrenia (SZ) and bipolar disorder (BD) are characterized by social impairments. Social impairment also occurs in the general community. Across clinical and nonclinical groups social impairment may be related to deficits in social approach and/or social avoidance motivation. However, the neural basis of social motivation deficits in SZ and BD is not well understood, nor is it known if they reflect features of the illness or are secondary to other factors such as social isolation. To fill these knowledge gaps, 31 individuals with SZ, 27 with BD, and 42 community comparisons (CCs) completed a team-based task during fMRI in which positive and negative feedback was provided by pictures of teammates or opponents. Importantly, the CC group was enriched for self-reported social isolation. fMRI analyses in five key regions of interest (ROIs; ventral striatum, orbital frontal cortex, insula, dorsal anterior cingulate cortex, amygdala), secondary whole-brain analyses, and associations between ROI activity and social approach/avoidance motivation were performed. Across groups, ventral striatum and amygdala showed greater activation to positive versus negative feedback. In SZ, ventral striatum activity to positive feedback was correlated with social approach motivation. In CCs, amygdala activity during negative feedback was correlated with social avoidance motivation. Whole-brain analyses revealed greater activation in BD compared to SZ and CCs in fronto-parietal regions when feedback was provided by an opponent. Findings support disturbed reward sensitivity as a core component of poor social approach motivation in SZ and offer avenues for future research into neural mechanisms underlying social impairment in BD and the general community.