Obesity and depression: same disease, different names?

Obesity is a major public health problem, which occurs in epidemic proportions. Our understanding of the systems of the brain related to energy balance has increased over the last decade. As a result, drugs most commonly used today in the management of obesity have their primary effect in modulating the balance between monoaminergic neurotransmitters, among other serotonin. Serotonin is believed to be involved in the complex process of integrating physiological and behavioral systems geared towards energy balance. However, gradual weight gain seen in most people suggests that the regulatory system may not be sufficient under all circumstances. An insufficient serotoninergic neuronal function in the central nervous system has been shown in many studies to occur in patents with depression. In such serotonin-deficient patients, treatment with drugs increasing the concentration of serotonin at serotoninergic synapses gives a favorable clinical response. Taken together, this suggests to a certain extent a common pathophysiology between obesity and depression. Literature spanning several decades has addressed the relationship among obesity and depression. However, obesity and depression research have evolved as two independent disciplines, which rarely or never overlap. In this paper, we propose the notion that obesity and depression may represent different manifestations of the same disease process - Janus faces of the modern society.