Perception or Reality of Body Weight: Which Matters to the Depressive Symptoms

Background: Failure to control for the confounding effects from body perceptions may contribute to the inconsistency of literature on the relationship between body weight and depression. The aim was to determine if perception mediates the associations between measured weight and depression.

Methods: We analyzed the data of 13,548 adults age 18 or older, collected in the National Health and Nutrition Examination Survey, 2005-2008. Depression status was ascertained using the Patient Health Questionnaire; and the BMI was calculated from measured height and weight.

Results: Among women, adjusting for perception weakened the relationship between measured weight and depression. The odds ratios (OR) of depression for being obese and overweight were 2.26 [95% confidence interval (1.50-3.40)] and 1.92 (1.29-2.85) before being adjusted for perception and 1.72 (1.01-2.92) and 1.62 (1.01-2.60) when perception was adjusted for. Independent from measured weight, women who perceived themselves as underweight [OR=2.95(1.47-5.14)] or overweight [1.73 (1.14-2.61)] had an increased odds of depression compared with women who perceived themselves as about the right weight. Among men, measured weight, neither overweight nor underweight, was associated with depression, perceiving oneself as underweight [OR=2.80 (1.42-5.54)] was associated with depression.

Limitation: The inherent limitation of the study's cross-sectional design prevented the authors from investigating causality.

Conclusion: Perception may be more important than measured weight in the relationship with depression. Independent from measured weight either perceived under or overweight among women, or underweight among men, appear to be significantly associated with depression.