Prof. Terrie E. Moffitt, Ph.D.
Duke University, Durham
Department of Psychology and Neuroscience
Terrie Moffitt’s first contribution to child psychiatry has been to understanding the origins of severe antisocial behavior. She is known for her discovery that young people engaging in delinquent behaviors can be characterised in a taxonomy of two distinct types: One type of antisocial behavior is called “life-course persistent” (LCP). It is a neurodevelopmental disorder afflicting primarily males, with very low prevalence in the population, genetic predisposition, adverse family environment, early childhood onset, and persistence of violent offending into midlife. The other type of delinquent behavior is called “adolescence limited” (AL). It affects females as well as males, is common, limited mainly to the adolescent age group, and emerges in the context of peer social relationships. The paper (Moffitt, 1993) which articulated this taxonomy has had a profound impact on psychiatry, psychology, criminology, and law, and is a citation classic. The idea behind Moffitt’s developmental taxonomy has proven broadly useful to researchers, diagnosticians, the American justice system and policy makers.
Moffitt’s second contribution has been to the study of gene – environment interaction. The notion of gene-environment interaction was around for many years, but it remained an abstract statistical concept in psychiatry until 2002 and 2003, when Moffitt’s group reported evidence of gene-environment interactions in conduct disorder and depression. The initial gene-environment interaction findings met with healthy skepticism, because genetic findings notoriously fail the test of replication. However, these initial findings of gene-environment interaction have seen a healthy replication record. Moreover, subsequent neuroimaging research and animal studies have further elaborated the nomological networks surrounding these specific gene-environment interactions. Mental-health practitioners who design interventions will gain new information about the biological effects of environmental risk factors, which will lead to new interventions to modify these effects and prevent mental disorders. Second, gene-environment interaction findings are proving to be influential in the public’s understanding of genetic science. These findings vividly contradict the public’s pervasive belief in genetic determinism, by showing examples of how genes’ effects on health and behavior often depend on lifestyle factors that are under human control. Public understanding of genetic science is being improved by supplanting the age-old idea of genetic determinism with the idea of gene-environment interaction.
Moffitt’s third contribution has been to documenting the childhood origins—and in a surprising number of cases—the childhood onset of adult psychiatric disorders. Moffitt has discovered important evidence from her longitudinal-epidemiological research that as many as half of adults with a psychiatric disorder had diagnosable psychiatric disorder before age 15 years; sometimes the adult disorder was preceded by its juvenile counterpart but, remarkably, in many cases adult disorders were antedated by a broad array of juvenile disorders. The results of her work suggest that from one-quarter to one-half of adult psychiatric disorders in the population might be prevented by effective treatment of youths with psychiatric disorders. These findings underscore the importance of targeting mental health treatment and prevention efforts early in life. Moreover, they have encouraged the application of population-screening methods in primary care settings and in schools to detect and to refer those children most needing mental health treatment.
Rutter, M., Moffitt, T.E., & Caspi, A. (2006). Gene-environment interplay and psychopathology: Multiple varieties but real effects. Journal of Child Psychiatry and Psychology Annual Review, 47, 226-261.
Moffitt, T.E. (2005). Genetic and environmental influences on antisocial behaviors: Evidence from behavioral-genetic research. Advances in Genetics, 55, 41-104.
Moffitt, T.E., Caspi, A., & Rutter, M. (2005) Strategy for investigating interaction between measured genes and measured environments. Archives of General Psychiatry, 62, 473-481.