There is growing awareness that common mental health disorders are key contributors to the burden of disease in developing countries. Studies examining the correlates of mental health have primarily been carried out in urban settings and focused on the burden rapid economic change places on individuals. In these settings, poverty and low education are consistent predictors of anxiety and depressive symptoms. We argue here that these variables are proxies for insecurity, and that a more general model of symptoms of depression and anxiety should focus on locally salient forms of insecurity. Building on previous work in a seasonal subsistence setting, we identify food insecurity as a potent source of insecurity in a rural African setting, and then test whether seasonal changes in food insecurity are correlated with concomitant changes in a measure of symptoms of anxiety and depression among 173 caretakers. Results indicate that food insecurity is a strong predictor of symptoms of anxiety and depression (P < 0.0001), that changes in food insecurity across the seasons predict changes in symptoms of anxiety and depression (P < 0.0001), and that this is robust to the inclusion of covariates for material assets and household production. These results hold for individuals in both ethnic groups studied (Pimbwe and Sukuma); however, at the group level the burden falls disproportionately on Pimbwe. The results add to the growing literature on the causes of population level differences in mental health disorders and suggest new research avenues and strategies to link mental health disorders with variation in physical and biosocial outcomes. Am J Phys Anthropol, 2008. © 2007 Wiley-Liss, Inc.