This article has shown that obesity is related to several psychiatric disorders, the most thoroughly researched of which is depression. In both community and clinical populations, the observed relationship is more consistent in women than in men, and is stronger in more severely obese individuals. The presence of BED also is associated with elevated risk of additional psychopathology. Longitudinal research provides evidence to support a pathway from obesity to depression, as well as one from depression to obesity. Weight loss, particularly with nonpharmacologic methods, appears to have favorable group-level effects on mood, but may be associated with adverse outcomes for some individuals. Persons who require antipsychotic medications are at risk for weight gain and metabolic abnormalities, and their management should be informed by consensus guidelines.