Dr Evan Atlantis, the University of Adelaide's School of Medicine, said patients with symptoms of common mental illness should be considered for obesity and related chronic diseases, and vice versa.
The lead author of the editorial published in the British Medical Journal said: "A better understanding of the mechanisms for the apparent bi-directional risk between obesity and common mental disorders is needed for effective treatment and prevention.
He continued: "Obese people - especially those who perceive themselves as being overweight - often experience weight-related stigma and discrimination, and consequently present with symptoms of low self esteem, low self worth, and guilt. Obesity is associated with socioeconomic disadvantage and low levels of physical activity, both of which are strong predictors of depression.
"Obesity may constitute a chronic stressful state, which in turn can cause significant physiological dysfunction. Such dysfunction would then predispose individuals to depressed mood and associated symptoms."
The editorial offered remarks on a new research paper on the topic published in the same issue of the BMJ by Professor Mika Kivimaki from University College London.