Expressive suppression moderates the relationship between brain volume and mental health.

Emotion regulation plays a critical role in both physiological and psychological well-being. While previous structural neuroimaging studies have examined the relationship between emotion regulation strategies and brain volume in neurotypical individuals, the potential moderating role of these strategies in the association between brain volume and mental health variables remains largely unexplored. This study had three main objectives: (1) to employ an unsupervised, data-driven approach to cluster participants based on their use of cognitive reappraisal (CR) and expressive suppression (ES), alongside their scores on anxiety, depression, and perceived stress; (2) to compare the brain volume of regions of interest associated with emotion regulation across these groups; and (3) to investigate whether the frequent use of CR or ES moderates the relationship between brain volume and mental health outcomes. Fifty-three healthy adult participants completed self-report measures assessing their use of CR and ES, as well as anxiety, depression, and stress levels. High-resolution T1-weighted structural MRI scans were obtained to calculate brain volume. Unsupervised clustering identified two distinct groups based on emotion regulation strategy use and mental health scores. Cluster 1 showing greater volume in the left rectus gyrus compared to Cluster 2. Furthermore, moderation analyses revealed that frequent use of ES moderated the positive relationship between mental health symptoms and brain volume in the right superior frontal gyrus, left rectus gyrus, right amygdala, and bilateral insula. These findings underscore the importance of emotion regulation strategies in shaping mental health outcomes and their potential influence on brain structure in neurotypical individuals.