Fear of missing out (FOMO) associates with reduced cortical thickness in core regions of the posterior default mode network and higher levels of problematic smartphone and social media use

Fear of missing out (FOMO) promotes the desire or urge to stay continuously connected with a social reference group and updated on their activities, which may result in escalating and potentially addictive smartphone and social media use. The present study aimed to determine whether the neurobiological basis of FOMO encompasses core regions of the reward or social brain, and the associations with the level of problematic smartphone or social media use. We capitalized on a dimensional neuroimaging approach to examine cortical thickness and subcortical volume associations in a comparably large sample of healthy young individuals (n = 167). Meta-analytic network and behavioral decoding were employed to further characterize the identified regions. Higher levels of FOMO associated with lower cortical thickness in the precuneus. In contrast, no associations between FOMO and variations in striatal morphology were observed. Meta-analysis decoding revealed that the identified precuneus region exhibited a strong functional interaction with the default mode network (DMN) engaged in social cognitive and self-referential domains. Together the present findings suggest that individual variations in FOMO are associated with the brain structural architecture of the right precuneus, a core hub within a large-scale functional network resembling the DMN involved in social and self-referential processes. FOMO may promote escalating social media and smartphone use via social and self-referential processes rather than reward-related processes per se. ### Competing Interest Statement The authors have declared no competing interest.