Association between schizophrenia and psoriasis: A two-sample bidirectional Mendelian randomization study

Area of Science:

• Psychiatry and Dermatology
• Genetic Epidemiology

Background:

• Observational studies suggest a link between schizophrenia and psoriasis.
• The causal relationship between these conditions remains unclear.

Purpose of the Study:

• To investigate the potential causal association between schizophrenia and psoriasis using a bidirectional Mendelian randomization approach.

Main Methods:

• A two-sample Mendelian randomization (MR) analysis utilized genome-wide association study data for schizophrenia (n=77,096) and psoriasis (n=462,933).
• Inverse-variance weighted, MR-Egger, and weighted median methods were employed, alongside sensitivity analyses to ensure result robustness.

Main Results:

• Genetically predicted schizophrenia was significantly associated with an increased risk of psoriasis (OR: 1.001, p=0.012).
• No significant causal effect of genetically predicted psoriasis on schizophrenia was detected (OR: 0.221, p=0.145).
• Sensitivity analyses revealed no evidence of pleiotropy or heterogeneity.

Conclusions:

• This study provides genetic evidence supporting a causal link where schizophrenia may lead to an increased risk of psoriasis.
• The findings contribute to understanding the complex interplay between psychiatric and dermatological conditions.