Date of Award
Master of Arts
This study investigated the etiology of preschoolers’ somatic symptoms and internalizing problems, using a twin sample. A specific focus was placed on the genetic (i.e., DRD4 and 5-HTTLPR) and environmental (i.e., SES, household chaos, family conflict, and maternal emotional stability) factors that were hypothesized to be associated with these problems. This project also explored the possible gene-environmental interactions (GxE) that may exist among these contributors. It was hypothesized that children who are at greatest risk due to their genotype, environment, or a combination of the two would display elevated somatic symptoms and internalizing problems, compared to children who were less at-risk due to these factors. Data from 252 families included in the Southern Illinois Twins/Triplets and Siblings Study (SITSS) at age 5 were examined. Results indicated a significant DRD4 x household chaos interaction predicting preschoolers’ somatic symptoms, demonstrating that children with the DRD4-7r genotype exhibited less somaticizing in highly chaotic homes. Additionally, 5-year-old internalizing problems were significantly predicted by the cumulative environmental risk factor created (i.e., top 15% of scores for each environmental variable in the current sample) and marginally by the additive genotypic risk factor (i.e., a summation of the DRD4 and 5-HTTLPR “risk” scores). These results provide additional insight into the factors that may place children at greater risk for somatic symptoms and internalizing problems.
This thesis is only available for download to the SIUC community. Others should
contact the interlibrary loan department of your local library.