Associations of trauma, early home environment, and genetic effects with risk for depression: Towards an examination of gene-environment interplay.

摘要

The purpose of this work was to contribute to the growing literature exploring the interplay between genes and environment by examining the context of trauma and how it relates to genetic effects with regard to depression. This work contextualized the experience of trauma by using a latent class analysis to define trauma classes based on the types and numbers of events experienced by individuals in the sample, and examined the early home environment correlates of each trauma class. Use of a genetically-informative twin sample allowed an assessment of the relative associations of trauma, early environment, and genetic effects with risk for depression.;The results are based on a secondary analysis of an existing Australian twin register. Subjects were 5180 twins (1118 MZ and 1472 DZ complete pairs) who had participated in a diagnostic interview that included questions about lifetime experience of trauma and early home environment. Lifetime diagnosis of depression was based on DSM-IV criteria.;A six-class solution was identified as the best fit to the data and the most appropriate to answer the research questions. Three of the trauma classes comprised ninety-five percent of the sample and endorsed no trauma or primarily nonassaultive events such as life-threatening accident. The remaining three classes comprised five percent of the sample and endorsed high rates of childhood sexual and physical abuse and neglect, as well as high rates of assaultive events.;Compared to individuals in the control class, who endorsed no trauma or primarily nonassaultive trauma, individuals in the three most severe trauma classes experienced their first trauma at earlier ages, and had the earliest onset and highest risk for depression. In these most severe trauma classes, but not the other classes, the effects of trauma on risk for depression outweighed genetic effects. Not having a close relationship with parents was the only measure of early environment equal in magnitude to the association of early trauma with risk for depression. These results have implications for the prevention and treatment of depression, and also generate new questions for exploring the interplay between genes and environment.