Deciphering the shared genetic architecture between schizophrenia and suicide attempt: a statistical genomic study

Area of Science:

• Psychiatric Genetics
• Neuroscience
• Genomics

Background:

• Growing evidence suggests a reciprocal comorbidity between schizophrenia (SCZ) and suicide attempt (SA).
• Limited understanding exists regarding the shared genetic architecture underlying SCZ and SA.
• This study aimed to investigate the genetic correlation and causality between SCZ and SA.

Purpose of the Study:

• To investigate the genetic correlation and causality between schizophrenia (SCZ) and suicide attempt (SA).
• To identify shared genetic loci and understand the tissue-specific enrichment of associated genes.
• To provide a foundation for future mechanistic studies and the discovery of therapeutic targets.

Main Methods:

• Utilized genome-wide association summary statistics from European ancestry.
• Employed Linkage Disequilibrium Score Regression (LDSC) and ρ-HESS for genetic correlation analysis.
• Conducted cross-trait meta-analyses, colocalization, and bidirectional Mendelian randomization (MR) to identify shared loci and causality.
• Assessed tissue-level heritability enrichment using Stratified LDSC and MAGMA.

Main Results:

• A significant positive genetic correlation (r_g = 0.48) was found between SCZ and SA.
• Identified 13 distinct genomic regions and 79 independent loci associated with both traits.
• Discovered five novel shared loci and confirmed SCZ genetically predicts SA (OR 1.17) with no evidence of reverse causality.
• Gene enrichment analysis highlighted predominant expression in brain tissues, including cortical and limbic regions.

Conclusions:

• Schizophrenia and suicide attempt share a significant genetic architecture.
• Overlapping pleiotropic variants, tissue-specific expression, and functionally shared genes underpin this association.
• Findings reveal underappreciated genetic overlaps, offering a framework for future research into mechanisms and therapies.