Cortisol is a corticosteroid hormone produced by the adrenal cortex. It is usually referred to as the “stress hormone”. It is involved when the body is under stress or anxiety. It increases blood pressure and blood sugar and reduces immune responses. It also has other functions such as converting fat, carbohydrate and protein into energy. This hormone is usually concentrated in the early morning, then starts to drop in late morning and finally reaches its lowest point in the evening.

This study was led by Panagiota Pervanidou, MD of Athens University Medical School in Athens, Greece. They measured the cortisol levels of obese children five times a day who have no prior symptoms of depression. They collected saliva samples as well as blood samples in the morning. The collected saliva samples in the afternoon and in the evening associated positively with symptoms of depression.

Obesity and depression have been linked together and the possible underlying cause may be hormonal in nature. Prevention and screening for obesity and depression should start as early as childhood. The researchers further recommended giving more focus on female adolescents who have the highest risk of developing depression, obesity or anorexia.

From Science Daily:

A new study connects abnormalities of the “stress” hormone cortisol with symptoms of depression in obese children, and confirms that obesity and depression often occur together, even in children. The results were presented at The Endocrine Society’s 91st Annual Meeting in Washington, D.C.