Risk mechanisms in development: Some conceptual and methodological considerations.

This commentary focuses on several issues concerning research on risk mechanisms that are raised in this special issue. First, we focus on what marks this special issue as distinctive in the ways in which risk research is conducted. Second, several general issues in research are highlighted, including sample characteristics, measurement strategies, specificity of risk factors and risk mechanisms, categorical vs. dimensional approaches to samples and measures, and definitions of development and transitions. Third, the challenges for integrating alternative models of risk are discussed, with special references to research on genetic and environmental influences on developmental psychopathology.