Quantitative genetics and developmental psychopathology: Contributions to understanding normal development

Abstract

This article reviews ways in which quantitative genetic approaches to developmental psychopathology can elucidate normal development. A few examples from genetics are discussed to highlight how investigations of abnormal functioning can inform the study of normal functioning. Two topics that provide bridges between the normal and abnormal are presented in greater detail. Most important is a new quantitative genetic technique that assesses empirically genetic and environmental links between the normal and abnormal. A second topic involves quantitative genetic approaches to environmental analyses, as highlighted by the examination of nonshared environmental factors. Such examinations of the environment are essential in studies of psychopathology, and their application to abnormal development can elucidate processes of normal development. We believe that forging links between the normal and abnormal is the core task of developmental psychopathology and that quantitative genetics is not only compatible with this goal, but essential to it.