Causal association between benign anorectal disorders and mental disorders: A Mendelian randomization study

Area of Science:

• Psychiatry
• Gastroenterology
• Genetics

Background:

• A strong association exists between benign anorectal diseases and mental health.
• The causal relationship between these conditions is not well understood.

Purpose of the Study:

• To investigate the causal effects of common mental disorders on benign anorectal disorders using Mendelian randomization.
• To assess the direct and independent causal effects, and genetic correlations between these conditions.

Main Methods:

• Two-sample Mendelian randomization (MR) analysis using genome-wide association study summary data.
• Applied inverse variance weighting, MR-Egger regression, and weighted median methods.
• Conducted sensitivity analyses, multivariable MR, reverse MR, and linkage disequilibrium score regression (LDSC).

Main Results:

• Depression showed a significant causal effect on hemorrhoids (P=.0018) and a potential effect on anorectal abscesses (P=.0208).
• Schizophrenia demonstrated a potential causal effect on hemorrhoids (P=.0117).
• Sensitivity analyses indicated stable and reliable results, with no significant heterogeneity or pleiotropy. Significant genetic correlations were found between depression and both hemorrhoids and anorectal abscesses.

Conclusions:

• Depression causally impacts hemorrhoids and anorectal abscesses.
• Schizophrenia has a potential causal effect on hemorrhoids.
• The findings support a causal link between specific mental disorders and benign anorectal diseases.