According to major surveys, major depressive disorder affects nearly 15 million Americans (about 7% of the adult population) in a given year. While depression is an illness that can affect anyone at any time in their life, the average age of onset is 32 (although adults ages 49 - 54 years are the age group with the highest rates of depression.). Other major risk factors for depression include being female, being African-American, and living in poverty.
Depression in Women
Women, regardless of nationality, race, ethnicity, or socioeconomic level, have twice the rate of depression than men. (Women with depression may also have accompanying eating disorders, such as anorexia nervosa and bulimia. [For more information, see In-Depth Report #49: Eating disorders.]) While men are more likely than women to die by suicide, women are twice as likely to attempt suicide.
The causes of such higher rates of depression may be due in part to hormonal factors:
- Puberty. While both boys and girls have similar rates of depression before puberty, girls have twice the risk for depression once they reach puberty. In addition to hormonal factors, sociocultural factors may also affect the development of depression in girls in this age group.
- Menstruation. While many women experience mood changes around the time of menstruation, a small percentage of women suffer from a condition called premenstrual dysphoric disorder (PMDD). PMDD is a specific psychiatric syndrome that includes severe depression, irritability, and tension before menstruation. [For more information, see In-Depth Report #79: Premenstrual syndrome.]
- Pregnancy and Childbirth. Hormonal fluctuations that occur during and after pregnancy, especially when combined with relationship stresses and anxiety, can contribute to depression. Post-partum depression is a severe depression (sometimes accompanied by psychosis) that occurs within the first year after giving birth. The rapid decline of reproductive hormones that accompany childbirth may play the major role in postpartum depression in susceptible women, particularly first-time mothers. Studies suggest that women who are more sensitive to hormone fluctuations are at greater risk for postpartum depression if they have a personal or family history of depression. Miscarriage also poses a risk for depression.
- Perimenopause and Menopause. Hormonal fluctuations that can trigger depression also occur when a women is transitioning to menopause (perimenopause). Sleep disruptions are also common during perimenopause and may contribute to depression. Once women pass into menopause, depressive symptoms generally tend to wane. [For more information, see In-Depth Report #40: Menopause.]
Depression in Men
Depression is not rare in men. In fact, white men over age 85 have the highest rates of suicide of any group. Men may be more likely than women to mask their depression by using alcohol. Some research suggests that depression in men is associated with the following indicators:
- Low tolerance to stress
- Behaviors such as "acting out" and being impulsive
- A history of alcohol or substance abuse
- A family history of depression, alcohol abuse, or suicide
Review Date: 01/27/2011
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.