Genetics of Disordered Gambling

Abstract

Abstract There is evidence from twin studies that genetic variation contributes to individual differences in the risk for disordered gambling (DG), and that some of this genetic variation overlaps with the genetic risk for other comorbid disorders such as alcohol dependence, antisocial behaviour disorders and major depression. It is likely that the specific genes that contribute to DG risk will be of small effect; there are no established susceptibility genes for DG. The most promising candidates based on theory and cumulative evidence are dopamine system genes. Other interesting leads come from the norepinephrine system, including the ADRAC2 and MAO‐A genes, and several novel variants identified in a recent genome‐wide association study. Genetic research on DG is in its infancy, with most of the interesting findings based on single unreplicated studies. There is much uncharted territory in research on the genetics of DG. Key Concepts: Disordered gambling affects approximately 1–2% of the population in the United States, and many individuals who do not qualify for a clinical diagnosis may also experience substantial harms from their gambling involvement. There are cross‐national and cross‐temporal differences in the prevalence of disordered gambling, highlighting the importance of nongenetic factors. Twin studies suggest that the variation in risk for disordered gambling among adults is due to genetic and unique environmental influences, with no evidence for an important role of the shared family environment. The contribution of genes and environment to disordered gambling risk appears to be similar among men and women. Genetic variation in disordered gambling risk overlaps with the genetic risk for other comorbid disorders such as alcohol dependence, antisocial behaviour disorders and major depression. Genetic susceptibility for DG will also include those genes related to individual differences in the earlier stages of gambling involvement. Like other complex polygenic disorders, genetic variation in disordered gambling risk appears to be due to many genes of small effect. There are no known susceptibility genes for disordered gambling; the most promising candidates are the dopamine system genes, with other interesting leads from the norepinephrine system. The much‐needed research on disordered gambling endophenotypes will improve the understanding of the pathways from genes to disordered gambling and may facilitate efforts to identify susceptibility genes. There is little research evaluating the potential disordered gambling endophenotypes, but the broader disordered gambling literature suggests that neural systems, cognitive distortions and decision making, personality traits such as impulsivity and negative emotionality, and loss‐chasing are viable candidates.