Bidirectional Relationship Between Atopic Dermatitis and Psychiatric Comorbidities in Individuals of European Ancestry: A Mendelian Randomization Study.

This study looked at whether skin conditions like eczema (atopic dermatitis) and mental health conditions cause each other. Using genetic data from many people, researchers found that having eczema increases the chance of developing anxiety. They also found that having bipolar disorder increases the chance of developing eczema. However, they found no clear connections between eczema and autism, ADHD, depression, or other mental health conditions.

This 2025 Mendelian randomization study investigated bidirectional causal relationships between atopic dermatitis and eight psychiatric conditions in individuals of European ancestry. Using genetic instruments from large-scale genome-wide association studies, researchers found that atopic dermatitis causally increases anxiety risk (OR=1.110, 95% CI: 1.019-1.208, p=0.016). Conversely, bipolar disorder causally increases atopic dermatitis risk (OR=1.062, 95% CI: 1.018-1.107, p=0.005). No significant causal relationships were identified for autism spectrum disorder, ADHD, depression, suicidality, obsessive-compulsive disorder, or schizophrenia.

Sensitivity analyses confirmed robustness with no evidence of horizontal pleiotropy. The findings support integrated dermatological and psychiatric care approaches.

Findings support integrated care approaches combining dermatological and psychiatric services. Early mental health screening recommended for atopic dermatitis patients, particularly for anxiety symptoms. Dermatological evaluation should be considered for individuals with bipolar disorder. Results inform targeted intervention strategies.

Study limited to European ancestry populations, limiting generalizability to other ethnic groups. Sample sizes not reported. Underlying biological mechanisms not explored. Requires validation across diverse populations and investigation of mediating pathways between identified causal relationships.

Atopic dermatitis is a chronic inflammatory skin disorder that significantly impacts quality of life and is often associated with psychiatric comorbidities. How-ever, the causal relationship between atopic dermatitis and psychiatric disorders remains unclear. This study employed bidirectional 2-sample Mendelian randomization to investigate the potential causal relationships between atopic dermatitis and 8 psychiatric conditions: depression, anxiety, autism spectrum disorder, attention deficit hyperactivity disorder, suicidality, bipolar disorder, obsessive-compulsive disorder, and schizophrenia. Genetic instruments were derived from large-scale genome-wide association studies of European ancestry.

Forward Mendelian randomization analysis indicated that atopic dermatitis causally increases the risk of anxiety (inverse variance weighting p = 0.016; odds ratio = 1.110, 95% confidence interval: 1.019-1.208). Reverse Mendelian randomization analysis revealed a significant causal effect of bipolar disorder on increasing the risk of atopic dermatitis (inverse variance weighting p = 0.005; odds ratio = 1.062, 95% confidence interval: 1.018-1.107). No significant causal relationships were found for other psychiatric conditions. Sensitivity analyses confirmed the robustness of these findings, with no evidence of horizontal pleiotropy.

These results highlight the need for integrated dermatological and psychiatric care, emphasizing early mental health screening for atopic dermatitis patients and dermatological evaluation for individuals with bipolar disorder. Future research should explore underlying biological mechanisms and validate findings across diverse populations.