An innovative study published in Psychotherapy and Psychosomatics has explored the genetic relationship between childhood trauma and emotional inhibition (alexithymia). Existing evidence suggests that both genetic and environmental factors contribute to the development of alexithymia. However, the composition of environmental as well as genetic factors and their putative interaction are incompletely understood.
Using data from 5,283 subjects (general population), this study investigated direct and interactional effects of childhood trauma and the 5-HTTLPR (bi- and triallelic) polymorphism on alexithymia. Results showed strong associations of neglect and abuse and significant effects of the low-expressing alleles (S; LG) of 5-HTTLPR with alexithymia. In other words, childhood abuse and neglect are strong predictors of alexithymia suggesting that different etiological pathways may result in the development of alexithymia. In addition, variants of 5-HTTLPR were associated with the affective factors such as difficulties identifying feelings and difficulties describing feelings, which have been shown to be particularly relevant for impaired emotion regulation.
Concepts that relate childhood neglect to alexithymia state that perceived lack of attention and insufficient exposure to adaptive emotional learning can lead to impaired emotion regulation of alexithymic subjects. Regarding associations between childhood abuse and alexithymia, it has been suggested that alexithymia serves as a defense mechanism against intolerable thoughts and feelings. As no interactional effects were found, a coexistence of environmental as well as genetic factors may independently result in alexithymic personality traits.