Women face almost twice the risk compared to men of having a major depressive disorder during their lifetimes.The reason for this greater risk is unclear, but a combination of biological, hormonal, genetic, psychological and social factors appear to play a role.
"Women are definitely hit harder by depression, and they are more vulnerable to the illness due to biology," said Jill Goldstein, director of research at the Connors Center for Women's Health and Gender Biology at Brigham and Women's Hospital in Boston.
Scientists including Goldstein are beginning to unravel the role of sex differences in the development and functioning of the brain, and how these differences affect psychiatric disorders.
Although women are generally more attuned to changes in the way they are feeling and often better able to express these symptoms to others, making them more likely to seek treatment, this doesn't fully explain why women may be disproportionately affected by depression compared with men, Goldstein said.
Here are 6 reasons why women could be hit harder by depression than men.
Genetic vulnerability: A family history of depression increases both women's and men's chances of developing the disorder. But a genetic vulnerability coupled with stressful life events, especially those occurring earlier in life such as childhood sexual or physical abuse, might contribute to a higher incidence of depression in women, Goldstein said. Research suggests that women are more likely than men to become depressed in response to a stressful event. [Wonder Woman: 10 Interesting Facts About the Female Body]
Fetal development: During fetal development, sexual differentiation occurs in the brain, allowing some brain regions to develop differently in men than in women, Goldstein said.
In addition, hormones and genes that get disrupted during fetal and early childhood development could lay the groundwork that makes some people more vulnerable to mood disorders, such as depression, she explained.
Depression may also emerge during three other sensitive periods during a woman's lifetime, Goldstein said.
All three periods occur when hormones flood a woman's brain and body. These hormones directly affect brain chemistry, and this suggests a hormonal regulation of the circuitry in the brain that in turn regulates mood and emotions, she explained.
During these periods, women need to check in with themselves, to observe changes in their moods, concentration, energy, and sleeping and eating habits. This is particularly true for women who have had a previous depressive episode; they face a greater risk for developing the illness again during pregnancy or menopause.
Adolescence: Before puberty, there are fewer sex differences in depression, and the disorder affects boys and girls are equally. The sexdifferences emerge in teenagers after puberty, sometime between ages 16 and 20, when girls are about twice as likely to become depressed.
If depression runs in the family, it's important for women to keep on eye out on their kids, especially after puberty, Goldstein said.
Pregnancy: "Pregnancy can be a catalyst for major depression in women," Goldstein told Live Science.
Hormonal fluctuations during and after pregnancy contribute to this heightened risk. Problems conceiving a baby, an unwanted pregnancy or a miscarriage can all also contribute to depression.
After delivering, the demands of motherhood and caring for a newborn can feel overwhelming. While some women may have a short period of the "baby blues," postpartum depression is a more serious, longer-lasting and disabling condition.
Transition to menopause: The rise and gradual fall of reproductive hormones in the years leading up to and during menopause can contribute to depression. This time period, called perimenopause, can bring both physical and psychological changes that can also influence women's moods. Those changes can include hot flashes, heavy bleeding, irregular periods and insomnia.
Environmental influences: The way women are raised in society and the roles they often play in it can affect their susceptibility to depression, too. A woman's role as a mother, wife and caregiver for aging parents, along with the pressures of her home and work life, can increase stress. And this stress can lead to depression in some women. Research shows that women tend to be more sensitive to their own emotions as well as the emotional needs of others, and they may internalize these emotions and dwell on them, which can leave these women with symptoms that can lead to depression.