Gene-Environment Interactions in the Prediction of Antisocial Phenotypes

Dr. Matthew Robinson (2004) proposed a new inclusive theory of human criminal behavior, entitled Integrated Systems Theory. This theory put forth by Robinson (2004) and later Robinson and Beaver (2009), hypothesizes that human behavior is far too complex for any one theory or any one behavioral discipline to accurately predict and examine; rather the study of human behavior should include factors from multiple theories and disciplines. Integrated Systems Theory hypothesizes that human behavior is influenced by multiple factors across the life course, both biological and environmental. These proposed factors are exhaustive and include six different levels of influence, the cellular level, the organ level, the organism level, the group level, the community level, and the societal level. These factors include, but are not limited to, deviant peers, brain development, toxin exposure, genetic functioning, neighborhood characteristics, family structure, routine activities, and gender and racial inequality across the societal level. Integrated System Theory further expounds upon its hypotheses by positing that while these various factors all influence behavioral development, one key relationship also plays an important role, the interplay between genes and environment. It hypothesizes that all human behaviors are the result of interactions between genes and the environments that an individual is exposed to across the life course (Robinson, 2004; Robinson & Beaver, 2009). Currently, due to the exhaustive nature of this theory no empirical study has yet sought to test its various tenants. Therefore, this dissertation seeks to examine facets of this theory by focusing on the role played by both biological and social factors in the prediction of antisocial phenotypes. Focusing on the risks of prefrontal cortex development, cumulative genetic risk, deviant peers, maternal risk, socioeconomic status, school attachment, and neighborhood disadvantage, the influence of these contributors upon human behavior will be examined. Further, gene-environment interaction terms will be developed between cumulative genetic risk and the chosen environmental risks, to determine if these five different gene-environment interaction terms are strong contributors to antisocial phenotypes. To determine the relationship between these environmental and genetic factors in influencing human behavior, a range of antisocial outcomes will be predicted within negative binomial models. Outcomes include drug abuse, violent crime, property crime, and arrest rates. This dissertation seeks to determine if tenants of the Integrated Systems Theory are supported or refuted by the data and analyses. Results generated within the analyses indicated partial support for Integrated Systems Theory. Within the models brain development played a significant role in behavioral development. The importance of direct environmental effects were also generally supported within the data; deviant peer and school attachment emerged as some of the more robust environment contributors to antisocial phenotypes. Direct genetic effect failed to display consistent predictive power across the various negative outcomes. The importance of gene-environment interplay was generally supported within the models as well, especially when interacting with deviant peers and in the prediction of drug abuse and arrests rates. The meaning of the results, potential limitations, and contribution to the literature are discussed.