A better understanding of the etiology of heroin dependence is crucial for improving the prevention and treatment of this severe mental disorder. Genes that could be risk factors for heroin dependence have not been consistently identified; however, genetic epidemiology studies have shown that they do have an impact. These studies, with one exception [1], also suggest that such genetic factors are mainly nonspecific, because they also confer vulnerability to other substance use disorders (SUD) [2-4].
