Do Hair Cortisol Levels Reflect Women’s Depression Risks?
All people affected by diagnosable major depression have symptoms such as “down” or negative emotions, agitation or anxiety, sleep disruption, altered appetite, fatigue, physical problems with no clear underlying causes, outbursts of anger, diminished mental clarity, suicidal thoughts and/or behaviors and a declining ability to feel pleasure or enjoy previously favored activities. In order to receive an official diagnosis under guidelines established by the American Psychiatric Association, an individual must experience severe forms of five or more of these symptoms every day or almost every day for at least two weeks. Doctors commonly refer to a bout of major depression as a depression episode. Some people who qualify for a diagnosis only experience one such episode over the course of their lives. However, in most cases, major depression recurs over time in multiple episodes.
Almost 7 percent of all American adults have major depression at any given time, the National Institute of Mental Health reports. For a number of underlying reasons (including biological predisposition, the impact of gender-based social roles and the impact of gender-based socioeconomic discrimination), women receive a diagnosis for the disorder about 70 percent more often than men. Caucasian women have particularly high depression risks. While the disorder can appear anywhere between childhood and old age, most individuals first develop symptoms in early adulthood.
Cortisol, Stress and Depression
Cortisol is produced in the paired adrenal glands, which sit on top of each kidney. In all human beings, levels of this hormone rise in response to increased levels of everyday or extraordinary stress. Other roles for cortisol include blood glucose (blood sugar) processing, blood pressure regulation, pain reduction and regulation of the tissue inflammation triggered by the body’s immune system. Unfortunately, repeated or chronic stress exposure can lead to an excessive release of the hormone into the bloodstream. Apart from any depression-related effects, potential consequences of excessive cortisol levels include reduced bone mass, reduced muscle mass, increased exposure to blood sugar-related health problems, impaired immune system function, reduced mental clarity and reduced output from the thyroid gland. In people with certain genetically inherited traits, high cortisol levels have been linked to increased chances of developing major depression; however, not all researchers make such a connection between cortisol levels and depression risks.
Hair Cortisol Levels and Depression in Women
In the study published in the Journal of Affective Disorders, researchers from China’s Sichuan University and Binzhou Medical University used a small-scale project involving 65 women to assess the usefulness of hair cortisol levels as an indication of women’s major depression exposure. Twenty-two of the study participants had experienced a single episode of major depression, while 13 had experienced recurring depression episodes. The remaining 30 participants did not have a major depression history and acted as a generally healthy comparison group. The researchers measured the cortisol levels in the hair of each person in all three participant groups. In addition, each participant took a major depression screening test called the Hamilton Depression Rating Scale.
The researchers concluded that, before entering a depressive episode, the women with first-onset depression and recurring depression had roughly the same hair cortisol levels as the healthy women unaffected by depression. While actively affected by depression, the women experiencing their first episode of the disorder had clearly elevated cortisol levels. However, cortisol levels did not increase by any significant amount during the depressive episodes of the women dealing with recurring major depression.
The study’s authors note that there was no clear relationship between the participants’ hair cortisol levels and their scores on the Hamilton Depression Rating Scale. However, their finding of increased cortisol levels in women experiencing depression for the first time points toward some sort of link between cortisol levels and women’s depression risks.