The bridge between psychology and genetics is not a one-way street. Although psychologists have much to learn from geneticists, they also have much to offer. As geneticists have grown interested in incorporating environmental information into genetic studies, they have been guilty of using environmental measures that would be considered naive by psychologists who are devoted to careful characterization of these constructs. Much of the large-scale gene identification work to date has been dominated by studies of binary diagnostic outcomes. Although the use of binary diagnoses brings the advantage of standardized, reliable assessments across studies and sites, there is reason to believe that these phenotypes are not ideal for gene finding. Psychologists have a long history of careful measurement of phenotype and of studying intermediate phenotypes and mechanistic processes. The application of these skills to the field of genetics holds great promise both to aid in gene identification and to help with the characterization of risk associated with identi-fied genes. However, this promise will only be recognized when psychologists and geneticists work closely together, have patience with one another concerning differences in training and ideology, and respect the relative contributions that each field can bring to the study of gene-environment interaction.
