Links Between Depression and Obesity in Teenage Girls
The term depression most typically refers to major depressive disorder (major depression), a severe, disabling condition that produces intense forms of the mental states classically associated with depression, as well as additional symptoms such as sleep disturbances, fatigue, lack of interest in pleasurable activities and suicide-related general thoughts, specific plans, or active behaviors. Other forms of depression include conditions called dysthymia (dysthymic disorder) and minor depression, as well as postpartum depression, seasonal affective disorder and psychotic depression. While all of these conditions differ from major depression in significant ways, they’re still capable of producing widespread destabilizing, negative effects on our well-being. Because of its depressive elements, bipolar disorder is sometimes also viewed as a form of depression; other experts include this condition along with depression in a larger group of mental illnesses known as mood disorders.
Cortisol is a product of the adrenal glands, a pair of hormone-producing organs at the top of the kidneys. Like all other hormones in the body, it serves a regulatory function by chemically triggering specific changes in normal cell activity. The adrenal glands release their cortisol supply as part of a chain reaction in the body’s natural response to stress. In the first stage of this chain reaction, a structure in the brain known as the hypothalamus produces a hormone, called CRH (corticotrophin-releasing hormone). This hormone travels from the hypothalamus to another brain structure called the pituitary gland, where its chemical influence leads to the release of a hormone known as ACTH (adrenocorticotropic hormone). In turn, cortisol release begins when ACTH in the bloodstream reaches the adrenal glands.
Cortisol’s primary mental effect is the promotion of stress-related states of mind such as fear and anxiousness. On a physical level, it helps support the body’s “fight-or-flight” response by doing such things as reducing hunger levels, preparing the immune system for increased activity, boosting the amount of cellular fuel (glucose) available in the bloodstream, and preparing the body’s tissue cells for the possibility of a significant injury.
Ties to Obesity
The presence of depression is a known contributor to abnormal activation of the body’s stress response and the subsequent elevation of the body’s cortisol levels. When teenage boys with depression are subjected to these stress-related changes, they do not typically experience significant increases in body weight. However, according to the results of a study published by an international research team in 2010 in the Journal of Adolescent Health, teenage girls in these same circumstances develop considerable risks for obesity. The researchers involved in this study drew their conclusions after examining a large group of teen and preteen boys and girls for symptoms of depression, determining which of these children qualified as obese according to standard public health definitions, and measuring the cortisol levels in the children’s saliva both before and after subjecting them to a series of tests designed to mimic the presence of everyday stress.
No one knows precisely why teenage girls experience this reaction to depression and stress. However, the authors of the study believe that the underlying cause of such a gender-specific response may be related to the unique body-altering effects of the sex hormone estrogen, which enters the female bloodstream at the onset of puberty. In addition, on a more straightforward but perhaps less explanatory level, teenage girls apparently have a greater tendency than teenage boys to increase their food intake when their stress levels rise.
The authors of the study published in the Journal of Adolescent Health believe that their findings may help point the way toward an effective reversal of the modern epidemic of teen obesity in the U.S. and elsewhere. If depression is indirectly linked to obesity through the body’s response to stress, then early identification and treatment of depression can reduce the impact of stress, and thereby reduce the chances for unhealthy weight gain in roughly half of the teenage population.