The neuroanatomical correlates of daily habitual tendencies and mediating effect on the association between daily habitual tendencies and symptoms of behavioral addictions

Abstract

Habitual behaviors significantly shape our daily actions. Furthermore, habit formation is proposed as a key mechanism contributing to the development and maintenance of addiction. However, the neural substrates underlying daily habitual tendencies and their contribution to behavioral addiction symptoms in everyday life remain poorly understood. To explore these questions, we conducted a comprehensive analysis of data from 219 individuals who underwent neuroimaging (structural MRI) assessments alongside evaluations of their daily habitual tendencies and symptoms of Internet Gaming Disorder (IGD) and Problematic Smartphone Use (PSU). Using voxel-based morphometry, meta-analytic decoding, and mediation analysis, we found that daily habitual tendencies were positively correlated with larger gray matter volumes in the ventromedial prefrontal cortex (vmPFC), precuneus, superior frontal gyrus (SFG), inferior temporal gyrus (ITG), and supplementary motor area (SMA). Notably, the midline regions, including the vmPFC and precuneus, play a crucial role in value-based computation, emotional regulation, social cognition, and self-referential thinking. Individual variations in gray matter volumes within these regions served as mediators, influencing the bidirectional relationship between daily habitual tendencies and IGD symptoms. However, vmPFC variations were specifically found to mediate the pathway from PSU to daily habitual tendencies. Our findings suggest that the morphological architecture of the vmPFC and precuneus is associated with habitual tendencies in daily life and may mediate the development of addictive behaviors. This study contributes to a more nuanced understanding of the neuroanatomical basis of daily habitual tendencies and their role in addictive behaviors.