Genetic and environmental influences on rumination and its covariation with depression

Abstract

This study examined the extent to which rumination and depression share genetic and environmental influences in a community sample of adult twins (N = 663). Twins completed multiple rumination questionnaires, a depressive symptoms questionnaire and a diagnostic interview. Rumination was moderately heritable (h² = .37–.41 for the latent variable) and substantially influenced by nonshared environmental factors, and these results were consistent across different measures. Nonshared environmental influences on rumination were larger for women than men. Depressive symptoms and diagnosis were influenced by genetic and nonshared environmental factors (h² = .30–.45). The genetic correlations between rumination and depression were moderate to large (rA = .40–.82), suggesting that a substantial proportion of the genetic influences on rumination overlap with those on depression. Results were similar when examining self-reported depressive symptoms and interview-based diagnosis of major depressive disorder. These results highlight the importance of rumination in the integration of cognitive and genetic models of depression risk.

Keywords:

• Rumination
• Brooding
• Reflection
• Depression
• Heritability

Preliminary results from this study were presented at the Annual Meeting of the Behavior Genetics Association in Edinburgh, UK in June 2012. The abstract of the presentation is published in Behavior Genetics (volume 42, issue 6, 2012).

Preliminary results from this study were presented at the Annual Meeting of the Behavior Genetics Association in Edinburgh, UK in June 2012. The abstract of the presentation is published in Behavior Genetics (volume 42, issue 6, 2012).

Notes

¹ The lack of significant dominant (D) genetic influences does not necessarily mean that there are no non-additive genetic influences on these constructs, but rather, may reflect the low power of the twin design to distinguish them from additive (A) genetic influences (Martin, Eaves, Kearsey, & Davies, 1978). Thus, we consider A to reflect broad-sense heritability.

² There was a significant gender difference in the magnitude of measure-specific genetic influences on the RRS-R in the RLV model and a marginal gender difference in genetic influences in the RRS-R univariate model. This gender difference may be unique to the construct of reflection, as it was not detected in the other measures of rumination (RRS-B, RRQ-Ru, RLV).