Testosterone is a human hormone normally associated with teenage boys, men, and the development of male sexual characteristics. However, this hormone is also normally found in small amounts in teenage girls and women. Scientific evidence gathered throughout the 2000s indicates that abnormally low or high testosterone levels can increase a woman\u2019s chances of developing some form of depression. High testosterone levels, in particular, appear to play a significant role in the onset of depression in women going through menopause. In women with low testosterone levels, treatment with low doses of the hormone may help decrease depression symptoms. Testosterone Basics Compared to postpubescent boys and men, postpubescent girls and women have only modest amounts of testosterone circulating in their bodies. The normal female level for the hormone ranges from 15 nanograms per deciliter of blood (ng\/dL) up to 70 ng\/dL. Still, the bottom end of the normal male testosterone range is more than four times greater than the upper end of the normal female range. Postpubescent girls and women produce the bulk of their circulating testosterone in their ovaries. Usually, testosterone-related problems in females occur when levels of the hormone rise too high. Apart from any problems directly related to depression, the US National Library of Medicine lists potential consequences of excessive testosterone levels in girls and women that include baldness similar to that found in men, unusual hair growth in other parts of the body, disruptions in monthly menstruation, and loss of breast tissue. Potential underlying reasons for heightened testosterone levels in girls and women include premature (precocious) puberty, the presence of a condition called congenital adrenal hyperplasia, and ovarian cancer. Testosterone and Depression Women in the US develop diagnosable cases of depression much more often than men. In part, these elevated risks likely stem from the more complex hormonal interactions that regularly take place inside women\u2019s bodies. Depression in women is associated with both abnormally low testosterone levels (below 15 ng\/dL) and abnormally high testosterone levels (above 70 ng\/dL), according to the authors of a study published in 2002 in the journal Maturitas. In another study, published in 2010 in the American Medical Association\u2019s Archives of General Psychiatry, a team of researchers from the University of Pittsburgh examined the relative influence of testosterone, the main female hormone estrogen and a hormone called follicle-stimulating hormone (FSH) on depression risks in women transitioning from their childbearing years into menopause. To make this determination, the researchers looked at shifting hormone levels in over 3,000 women, and also tested these women for depression symptoms with the help of a standard screening test for depression called the Center for Epidemiological Studies Depression Scale or CES-D. After reviewing their findings the authors of the study concluded that women who have unusually high levels of testosterone while transitioning into menopause have increased chances of developing a positive score for the presence of depression on the CES-D screening test. This finding holds true even when other menopause-related factors for depression are taken into account. The study\u2019s authors also concluded that shifting levels of estrogen and FSH during the menopausal transition are not associated with an increased risk for developing depression. Testosterone Treatment In a study published in 2009 in the journal CNS Spectrums, a team of researchers at the Harvard Medical School-affiliated Massachusetts General Hospital examined the effectiveness of an eight-week course of testosterone therapy in depressed women with unusually low testosterone levels who fail to respond to standard antidepressant treatment. The authors of the study chose to focus on this type of therapy because poor responses to antidepressants are fairly common in women, and also because doctors currently have relatively few options for successfully treating antidepressant-resistant patients. After eight weeks of low-dose testosterone therapy, 66 percent of the women participating in the study saw at least some improvement in their depression symptoms. Roughly half of the women who responded well experienced a more or less complete remission of their symptoms. Considerations The US Food and Drug Administration has not approved testosterone therapy as a treatment for any condition in women. In addition, an expert task force assembled in 2006 by the Endocrine Society declined to support the use of testosterone or any other male hormone in the treatment of women\u2019s medical conditions. One of the objections listed by this task force was a lack of a definitive scientific consensus on what exactly constitutes a low male hormone level in any given woman. Despite these considerations, doctors in the United States still use testosterone therapy quite frequently, particularly when treating postmenopausal women.