ADGRL3 (LPHN3) variants predict substance use disorder.

Area of Science:

• Genetics
• Psychiatry
• Neuroscience

Background:

• Externalizing disorders like ADHD, conduct disorder, and SUD share genetic risk factors.
• ADGRL3 (LPHN3) gene variants are linked to ADHD susceptibility, severity, and related behavioral issues.

Purpose of the Study:

• To investigate the association between ADGRL3 gene variants and susceptibility to SUD, a common comorbidity with ADHD.
• To determine if ADGRL3 variants can predict SUD risk in individuals with ADHD.

Main Methods:

• Utilized family-based, case-control, and longitudinal samples (n=2698) from ADHD-focused studies.
• Employed recursive-partitioning (classification tree) analyses integrating clinical, demographic, and ADGRL3 genetic data.
• Validated predictive models in a large, independent sample of individuals with severe SUD.

Main Results:

• Substance use disorder (SUD) was efficiently and robustly predicted in ADHD participants using genetic and clinical data.
• The predictive models for SUD remained highly effective in an independent, severe SUD cohort, confirming ADGRL3 as a risk gene.
• The specific SNP rs4860437 emerged as the predominant predictive variant for SUD.

Conclusions:

• ADGRL3 variants are significant genetic risk factors for SUD, particularly in the context of ADHD.
• The study introduces a novel methodological approach for identifying complex genetic interactions and predicting SUD risk.
• Findings have translational potential for early clinical assessment and risk stratification of individuals susceptible to SUD.