Though some might say that GWAS have failed because we cannot account for the genetic variance associated with disease, this represents a very narrow view of the field. We have convincingly identified genetic variants that contribute to addiction. If the progress in other medical disorders can be used as an example, the “big science” consortia that include the study of tens of thousands and potentially hundreds of thousands of people will soon discover new variants that contribute to addiction. We now know that the genetic risk is modest (OR 1.3 or less) for variants that are common in the population, but rarer variants may have somewhat stronger effect. The genetic vulnerability to addiction represents the combination of hundreds or thousands of genes of modest effect.
