Depressing Combinations

Like other experts in women’s mental health, the Bhatias believe the higher prevalence of depression in women is probably due to a combination of gender-related differences in cognitive styles, certain biological factors, and a higher incidence of social, psychological and economic stresses in females. They list the following specific risk factors for women:

  • family history of mood disorders
  • personal past history of mood disorders in early reproductive years
  • loss of a parent before the age of 10
  • childhood history of physical or sexual abuse
  • use of an oral contraceptive, particularly one with a high progesterone content
  • use of gonadotropin stimulants for treatment of infertility
  • persistent psychosocial stressors (for example, job loss, family illness, poverty)
  • loss of a social support system or the threat of such a loss (for example, through a death, move, divorce)

Other researchers have delved more deeply into genetics and female biology to determine how these factors may relate to one another and which— if any—explain why so many more women than men get depressed.

An Inherited Trait?

Stress obviously plays a role in depression, but do women experience different stressors than men, or do they simply respond to the same stressors in a different fashion?

Researchers at the Medical College of Virginia looked for clues about how females react to environmental stressors in a study of more than 1,000 twin sisters, about half of whom had a family history of depression. According to the study’s director, Kenneth S. Kendler, M.D., a professor of psychiatry at MCV, recent exposure to a stressful event increased the risk of depression for the twins without a family history of the disorder only six percent. For twins who had such a family history, however, the risk was more than doubled, to 14 percent.

This suggests that women with a family history of depression may have inherited a tendency toward becoming depressed themselves, Kendler and his colleagues concluded. But, as the National Institute on Mental Health (NIMH) points out, not every woman with a family history develops the illness, while others with no such family history do.

Hormonal Factors

Hormones have attracted considerable attention as a likely cause for the huge differences between rates of depression in women and men. After all, women’s hormone-related reproductive events—including menstruation, pregnancy, the postpartum period, infertility and menopause—often are associated with mood fluctuations, including depression.

But in a National Institute of Health booklet, Depression: What Every Woman Should Know, U.S. government experts acknowledge that although female hormones do affect emotions and moods, the specific biological mechanism linking hormones such as estrogen to depression has yet to be identified.

The NIH further notes that some types of female depression, such as those that happen during the postpartum period or at the onset of menopause, more often occur in women who have had previous depressive episodes, even though they may not have been diagnosed or treated earlier. Other reproductive events—such as pregnancy and abortion—do not seem to result in a higher incidence of clinical depression. This knowledge has prompted study of the relationship between female hormones and depression from a different angle.