Genetic Architecture of the Comorbidity of Alcohol Use Disorder and Chronic Pain - PROJECT SUMMARY/ABSTRACT
Alcohol use disorder (AUD) and chronic pain (CP) commonly co-occur. Data have shown that a history of
heavy drinking and/or AUD are reported by 16-25% of patients in treatment for CP, and pain has been
identified as one of the major risk factors for relapse among individuals with AUD. Substantial overlap between
AUD and CP in terms of neurological dysregulation has been reported suggesting that genetic influences may
underlie the co-occurrence of AUD and CP. Genetic studies examining AUD and CP independently have
documented moderate heritability of each, and initial evidence from genome-wide association studies (GWAS)
supports overlap at the genetic level. Nonetheless, our current understanding of the genetic architecture
underlying comorbidity between AUD and CP is limited. The proposed project is the first to systematically
bridge this knowledge gap by leveraging large-scale GWAS using summary and individual level data to address
two primary aims and a third exploratory aim: (Primary Aim 1) estimate the amount of shared genetic variance
that contributes to latent constructs summarizing alcohol and CP phenotypes and the unique genetic variance
that contributes to each phenotype using a theory-driven, multivariate approach; (Primary Aim 2) estimate the
extent to which AUD-CP comorbidity can be explained by shared genetic mechanisms vs. causal, bidirectional
relations between AUD and CP using an instrumental variable approach; and (Exploratory Aim) model
contextual moderators that might impact the genetic contributions to the development or maintenance of
AUD-CP comorbidity. These critical questions will be addressed by employing state-of-the-art statistical
genetics methods, such as genome-wide structural equation modeling, pairwise GWAS, Mendelian
randomization, and genome-wide complex trait analysis, which have been well-validated for investigating
genetic relations among psychiatric and physical health conditions. Because these methods differ in terms of
purposes and/or assumptions, a multimethod approach will be adopted to evaluate the robustness of the
findings and further enhance scientific rigor. As a result, this project will advance our understanding of the
genetic and environmental contributions to the etiologies of AUD, CP, and their comorbidity. Additionally, the
results of this project will provide preliminary data indicating the feasibility of more comprehensively studying
the effects of gene-environment interplay on AUD-CP comorbidity in future R01 applications.