Association of Genetic Factors and Gene-Environment Interactions With Risk of Developing Posttraumatic Stress Disorder in a Case-Control Study

Background: The dopamine receptor D2 (DRD2) and serotonin transporter (5-HTT) genes are associated with posttraumatic stress disorder (PTSD). However, it remains largely unknown whether these genes interact with environmental factors to affect the development of PTSD. Purpose: The purpose of this study was to examine the associations of gene polymorphisms and gene-environment interactions with the risk of developing PTSD among adolescent earthquake survivors. Method: A total of 183 adolescent survivors from an earthquake-stricken area participated in this study. Measures included a questionnaire about demographic characteristics and earthquake exposure, the PTSD Checklist-Civilian Version and the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, fourth edition disorders. Genotypes were analyzed by using the polymerase chain reaction-based restriction fragment length polymorphism. Results: The 5-HTTLPR and 5-HTTVNTR polymorphisms and earthquake exposure had statistically significant positive effects on PTSD. The interaction effects of 5-HTTLPR x Earthquake Exposure and 5-HTTVNTR x Earthquake Exposure were statistically significant. Conclusion: The development of PTSD is the result not only of a genetic effect and environmental factors but also of the interactive effect between gene and environment.