New genetic discoveries are also likely to arise from leveraging novel analytic approaches such as integrating GWAS with multiple ‘omics data generated across addiction-relevant brain tissues, even at the resolution of individual cell types and single cells. With the ever-expanding postmortem human brain resources being made available to the scientific community, the field has begun to unravel the biology of top GWAS-identified variants, including a few functional missense SNPs that alter susceptibility to developing nicotine dependence or alcohol use disorder and several noncoding SNPs that perturb gene regulation and influence nicotine dependence and substance use disorders. The recent availability of ‘omics data across multiple brain tissues has offered unparalleled opportunities to study the neurobiological underpinnings of addiction and led to somewhat unexpected connections, such as smoking- and alcohol-associated cis-eQTL SNPs specific to cerebellum [26, 34, 58]. In this era of precision medicine, genetic variant discoveries hold great promise in tailoring prevention and treatment strategies for addiction. Discovery of more genetic loci and biological characterization of the associated variants is needed to enhance our understanding of the neurobiology underlying addiction and lessen its widespread health consequences on individuals and the public health burden.
