About 1 in 5 women develop depression at some point in life. Women are nearly twice as likely as men to have depression. Depression can occur at any age, but it's most common in women between the ages of 40 and 59.

Some mood changes and depressed feelings occur with normal hormone changes. But hormone changes alone don't cause depression. Other biological factors, inherited traits and life experiences are also involved. Here's what contributes to depression in women — and what you can do about it.

Puberty

After puberty, depression rates are higher in females than in males. Because girls typically reach puberty before boys do, they're more likely to develop depression at an earlier age than boys. This depression gender gap lasts until after menopause.

Hormone changes during puberty may increase some girls' risk of developing depression. However, temporary mood swings related to changing hormones during puberty are normal — these changes alone don't cause depression.

Puberty is often associated with other factors that can play a role in depression, such as:

• Emerging sexuality and identity issues
• Conflicts with parents
• Increasing pressure to achieve in school, sports or other areas of life

Premenstrual problems

For most females with premenstrual syndrome (PMS), symptoms such as abdominal bloating, breast tenderness, headache, anxiety, irritability and a blue mood are minor and short-lived.

But a small number of females have severe and disabling symptoms that disrupt their studies, jobs, relationships or other areas of their lives. At that point, PMS may cross the line into premenstrual dysphoric disorder (PMDD) — a type of depression that generally requires treatment.

The exact interaction between depression and PMS remains unclear. It's possible that cyclical changes in estrogen, progesterone and other hormones can disrupt the function of brain chemicals such as serotonin that control mood. Inherited traits, life experiences and other factors appear to play a role.

Pregnancy

Dramatic hormonal changes occur during pregnancy, and these can affect mood. Other issues may also increase the risk of developing depression during pregnancy or during attempts to become pregnant, such as:

• Lifestyle or work changes
• Relationship problems
• Previous episodes of depression, postpartum depression or PMDD
• Lack of social support
• Mixed feelings about being pregnant
• Unwanted pregnancy
• Miscarriage
• Infertility
• Stopping use of antidepressant medications

Postpartum depression

Many new mothers find themselves sad, angry, irritable and prone to tears soon after giving birth. These feelings — sometimes called the baby blues — are normal and generally subside within a week or two. But more-serious or long-lasting depressed feelings may indicate postpartum depression, particularly if signs and symptoms include:

• Low self-esteem
• Anxiety
• Agitation
• Inability to care for your baby
• Thoughts of harming your baby
• Thoughts of suicide

Postpartum depression is a serious medical condition requiring prompt treatment. It occurs in about 10 to 25 percent of women. It's thought to be associated with major hormonal fluctuations that influence mood, predisposition to mood and anxiety disorders, birth complications, and poor social support.

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Jan. 19, 2013 See more In-depth