Exploring the bidirectional skin-brain axis: Mental health, dermatology-related quality of life, and the role of probiotics

The skin–brain axis plays a key role in connecting dermatological health, mental health, and the gut microbiota. This study investigated the associations between anxiety, depression, stress, dermatology-related quality of life (DLQI), and probiotic intake in 305 Brazilian adults. Women presented higher scores for anxiety (13.0 ± 10.5 vs. 7.7 ± 8.1, p <0.001), depression (15.9 ± 12.3 vs. 10.6 ± 10.8, p <0.001), and stress (20.0 ± 11.5 vs. 13.4 ± 9.8, p <0.001). Nearly half of the participants reported dermatological disorders, and more than half were at risk for at least one mental health condition. Strong correlations were observed among mental health outcomes (anxiety–depression r=0.770, anxiety–stress r=0.834, depression–stress r=0.806; all p <0.001), while DLQI showed weak but significant correlations with these scores. Associations between probiotic intake and anxiety, depression, and stress were inconclusive ( p >0.05), likely due to low intake levels. Multiple linear regression showed that stress and depression were independent predictors of anxiety, with a final model of R²=0.66 and p <0.01. The findings highlight the bidirectional nature of the skin–brain axis and the greater burden of psychological and dermatological symptoms in women. Further studies that incorporate culturally relevant dietary patterns and longitudinal designs are needed to clarify these interactions. • Women exhibit higher anxiety, depression, and stress scores. • Strong correlations observed among mental health outcomes. • Dermatology-related quality of life weakly correlates with mental health. • Probiotic intake shows no significant association with mental health.