We study psychopathology during adolescence, particularly the emergence of externalizing behaviors like substance use, delinquency, and risky sexual behavior.  We are currently focusing on two research streams.  First, how do individual differences in “normal” developmental processes, such as puberty, contribute to “abnormal” behavior?  Second, how do genetic risks interact with family and social environments to produce psychopathology (gene-environment interaction)? 

This research uses a variety of behavioral genetic methodologies, including twin and children-of-twins designs.  In addition to analyzing behavioral genetic data from the National Longitudinal Study of Adolescent Health and the Australian Twin Registry, we are also starting a new twin registry in central Texas: The Twin Project at the University of Texas.  Much of our research, including the Twin Project, is conducted in collaboration with the Tucker-Drob lab at the University of Texas.