The Molecular Genetics of Pathological Gambling

As gambling becomes available to more and more individuals in this country, the problem of compulsive or pathological gambling (PG) will also increase. As with other forms of addiction, both environmental and genetic factors are involved in PG. Identification of the genes that play a role in increasing a person's risk for PG will lead to a better understanding of the disorder and to more rational and effective treatment. Although studies of the molecular genetics of PG are just beginning, a number of interesting observations have been made and are reviewed in this article. As with other addictive behaviors, abnormalities in dopaminergic reward pathways a likely to be involved. Consistent with this, we have observed a significant association between PG and the D1, D2, D3, and D4 dopamine receptor genes. The fact that each these genes has an effect is consistent with a polygenic inheritance of a susceptibility to PG The involvement of multiple dopamine genes consistent with the “reward deficiency syndrome,” which suggests that addictive impulsive disorders are due, at least in part, to genetic abnormalities of the dopamine reward pathways. On the basis of this hypothesis, we describe other genes also likely to play a role in a person's susceptibility to PG.