In their recent report on body mass index (BMI), depressive symptoms, and overweight concerns in a group of third-grade children in northern California, Erickson and colleagues1 were somewhat cautious in their conclusions but pointed to a "modest association between depressive symptoms and BMI" in girls. The authors base their conclusion on a correlation between BMI and depressive symptoms of 0.14—hardly a correlation at all. Furthermore, as the authors note, the direction of causality in cross-sectional studies is difficult to determine.
Karen M. Kaplan. Weight and Happiness. Arch Pediatr Adolesc Med. 2001;155(4):525–526. doi:10.1001/archpedi.155.4.525