The 89th Annual Meeting of the American Association of Physical Anthropologists (2020)


Does the sex difference in upper body strength explain the sex difference in depression?

CAROLINE B. SMITH and EDWARD H. HAGEN.

Anthropology, Washington State University

April 16, 2020 34, Platinum Ballroom Add to calendar

Depression is a cross-cultural, burdensome disease which occurs more often in women than men. Physical assault specifically, and conflict more generally, are some of the most potent predictors of depression. One evolutionary model of depression proposes that depression occurs when a person is at risk of a fitness cost either imposed by social partners or exacerbated by their lack of support. Physically stronger individuals can protect themselves from assault or otherwise induce partners to change their behavior, whereas others might rely on bargaining by withdrawing from usual activities, the core feature of depression. Therefore, according to this model the sex difference in depression is due to the dramatic sexual dimorphism in physical formidability. Previous research found that grip strength, a measure of upper body strength, mediates most of the effect of sex on depression. The current study extends this finding by ruling out chronic disease and partner status as confounds and by replicating the study with new data.

Using data from the 2011-2012 phase of the National Health and Nutrition Examination Survey (NHANES), a large representative sample of US households (N=4192), the current study found that although chronic disease and partner status are risk factors for depression, they do not explain the effect of strength or sex on depression. Finally, these results were replicated in the 2013-2014 (N=4384) phase of NHANES albeit with reduced effect sizes. The sex difference in depression might be explained in part by the sex difference in physical formidability.