PENN STATE (US)—Depression raises stress hormone levels in adolescents, but may also lead to obesity in girls. Researchers say early treatment of depression may help reduce stress and control obesity.
“This is the first time cortisol reactivity has been identified as a mediator between depressed mood and obesity in girls,” says Elizabeth Susman, the Jean Phillips Shibley professor of biobehavioral health at Penn State.
Details are reported in the Journal of Adolescent Health.
“We really haven’t seen this connection in kids before, but it tells us that there are biological risk factors that are similar for obesity and depression.”
The hormone cortisol regulates various metabolic functions in the body and is released as a reaction to stress. Researchers have long known that depression and cortisol are related to obesity, but they had not figured out the exact biological mechanism.
Scientists believe the way girls cope with anxiety—by stress eating and estrogen release—may be why high cortisol reactions translate into obesity only for girls.
“The implications are to start treating depression early because we know that depression, cortisol, and obesity are related in adults,” says Susman.
If depression were to be treated earlier, she notes, it could help reduce the level of cortisol, and thereby help reduce obesity.
“We know stress is a critical factor in many mental and physical health problems,” Susman says. “We are putting together the biology of stress, emotions and a clinical disorder to better understand a major public health problem.”
Susman used a child behavior checklist to assess 111 boys and girls ages 8 to 13 for symptoms of depression. The children’s obesity and the level of cortisol in their saliva were measured before and after various stress tests.
“We had the children tell a story, make up a story, and do a mental arithmetic test,” explains Susman. “The children were also told that judges would evaluate the test results with those of other children.”
Statistical analyses of the data suggest that depression is associated with spikes in cortisol levels for boys and girls after the stress tests, but higher cortisol reactions to stress are associated with obesity only in girls.
“In these children, it was mainly the peak in cortisol that was related to obesity,” Susman explains. “It was how they reacted to an immediate stress.”
Researchers from Cincinnati Children’s Hospital Medical Center and University College London contributed to the study, which was supported by National Institutes of Health.
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