(i) To investigate whether there is an association between obesity and mental disorders in the general populations of diverse countries, and (ii) to establish whether demographic variables (sex, age, education) moderate any associations observed.

Thirteen cross-sectional, general population surveys conducted as part of the World Mental Health Surveys initiative.

Household residing adults, 18 years and over (n = 62,277).

DSM-IV mental disorders (anxiety disorders, depressive disorders, alcohol use disorders) were assessed with the Composite International Diagnostic Interview (CIDI 3.0), a fully structured diagnostic interview. Obesity was defined as a body mass index (BMI) of 30 kg/m2 or greater; severe obesity as BMI 35+. Persons with BMI less than 18.5 were excluded from analysis. Height and weight were self-reported.

Statistically significant, albeit modest associations (odds ratios generally in the range of 1.2–1.4) were observed between obesity and depressive disorders, and between obesity and anxiety disorders, in pooled data across countries. These associations were concentrated among those with severe obesity, and among females. Age and education had variable effects across depressive and anxiety disorders.

The findings are suggestive of a modest relationship between obesity (particularly severe obesity) and emotional disorders among women in the general population. The study is limited by the self-report of BMI and cannot clarify the direction or nature of the relationship observed, but it may indicate a need for a research and clinical focus on the psychological heterogeneity of the obese population.