Genetic and environmental sources of familial resemblance in anxiety

Familial clustering is a dominant characteristic of anxiety disorders. On the other hand, the underlying mechanisms of the intergenerational resemblance of anxiety have not been fully understood yet. We can help intra-familial transmission of anxiety disorders be prevented by solving the genetic and environmental sources of the familial resemblance in anxiety. Therefore, both parent-specific and twin-specific data are needed in order to acquire objective and in-depth estimates regarding the genetic and environmental sources of the resemblance between family members.

A study analyzed the data taken from 991 families who had twins of the same sex. The constant level of anxiety in the twins was evaluated by means of self-report (the State-Trait Anxiety Inventory) and parent self-report (STAI-T parent form), while the parents were evaluated through the constant anxiety self-report (STAI-T) inventory. A nuclear twin family model was established, and the genetic and environmental variants were predicted by using the data of the two surveys.

The results indicated that additive genetic (A), dominant genetic (D), and non-shared environmental effects (E) made significant contributions to constant anxiety, although familial environmental effects (F) and passive gene-environment correlations (rGE) were not effective in constant anxiety.  Sibling environmental effects (S) provided only self-report data, and they increased when genetic effects reduced from Wave 1 down to Wave 2.

The study emphasizes the significant role of the inheritance in the intra-familial constant anxiety resemblance. It revealed that, rather than common family settings, additive genetic effects explain the parent-offspring anxiety resemblance, and that they are a genetic mechanism in the intergenerational transmission of anxiety. The parent-offspring resemblance initially occurs as a result of the shared genetic structure, rather than direct environmental transmission. These results are of both theoretical and practical importance for anxiety disorders. Further research can enlarge our understanding of anxiety by analyzing the gene-environment interaction and gender differences.

REFERENCES:
– Ding, Q., Bi, D., Zhou, Y., Bai, X., & Li, X. (2021). Genetic and environmental sources of familial resemblance in anxiety: a nuclear twin family design. Psychological Medicine, 1–9. DOI: 10.1017/s0033291721001197