Genetic studies are uniquely capable of providing insight into the biological pathways involved in the development of alcohol and nicotine dependence because ethical considerations preclude many experimental research designs involving human subjects. The newest generation of human genetic studies exploits the copious natural variability in the genome to evaluate effects of specific gene variations on disease outcomes. Identification of these genes provides important first clues to the biological underpinnings of disease. Although the complexity of alcohol and nicotine dependence makes the search for genes more difficult, it also underscores the need for genetic studies of these disorders. If various developmental pathways can lead to these common addictions, it is unlikely that any single treatment or prevention approach will be optimal for all vulnerable people. Because human genetic studies can uncover diverse biological factors involved in these disorders, such approaches have great potential for alleviating the enormous public health burden stemming from alcohol and nicotine dependence.
