Associations between personality traits and depressive mood in long-term high-altitude hypoxia-exposed individuals: exploring indirect pathways through cortical structure

Personality plays a crucial role in human adaptation to natural and social environments. The Big Five personality traits are associated with variations in cortical structure and relate to depressive mood. However, how personality traits are associated with depressive mood through cortical structures in long-term high-altitude hypoxia-exposed individuals remains unclear. In this study, we conducted morphological brain measurements using magnetic resonance imaging (MRI) on 129 healthy adult participants who had long-term residence on the plateau. Personality traits and depression levels were assessed using the Chinese version of the Big Five Inventory and the Symptom Checklist-90, respectively. Correlation analysis revealed that extraversion was significantly positively associated with the thickness of the right insula; neuroticism was significantly negatively associated with the volume of the right insula; and conscientiousness was significantly positively associated with the volume of the left middle temporal gyrus (MTG). Mediation analysis showed that the thickness of the right insula was consistent with an indirect association between extraversion and depressive mood (indirect effect = -0.05, 95 % CI = [-0.1152, -0.0001]); the volume of the right insula was consistent with an indirect association between neuroticism and depressive mood (indirect effect = 0.04, 95 % CI = [0.001, 0.089]); and the volume of the left MTG was consistent with an indirect association between conscientiousness and depressive mood (indirect effect = -0.04, 95 % CI = [-0.0963, -0.0001]). These findings provide possible evidence that personality traits may be linked to depressive mood through their relationships with cortical structural measures in long-term high-altitude hypoxia-exposed individuals.