Depression.com reports that approximately 16 percent of all Americans will experience depression at some point during their lifetime. Although it can affect anyone, age and gender play a major role in the likelihood of developing depression.

• Women: According to the National Institute of Mental Health (NIMH), women are twice as likely as men to experience depression. Hormonal changes that occur throughout puberty, menstruation, menopause, pregnancy, miscarriage, and postpartum may be contributing factors to the increased rate of depression in women.
• Men: Although men’s risk for depression is lower than women’s, men are more likely to go undiagnosed and less likely to seek help for their symptoms. In fact, the rate of suicide in men is four times that of women (however, more women attempt it). Men are also more likely to mask their symptoms of depression with alcohol and drugs and typically feel more angry or irritable instead of sad and hopeless.
• Elderly: Losing loved ones, adjusting to living alone, and having a physical illness that reduces activity may all be factors that contribute to depression in older people. Many times, these symptoms are passed off as normal signs of aging, and older people often do not seek or receive treatment for their depression.

There are also a few other factors that may contribute to depression:

• Family History: In some families, major depression occurs generation after generation. However, it can also occur in people who have no family history.
• Trauma and Stress: A serious loss, financial problems, relationship problems, and other stressful situations can contribute to depression. It is also common to become depressed after a big change in your life such as a new job, graduation or marriage.
• Pessimistic Personality: People with low self-esteem that continually put themselves down are at a higher risk for depression as well as other diseases. Click here to learn about the link between optimism and cardiovascular health.
• Physical Conditions: Medical illnesses such as stroke, heart disease, cancer, Parkinson’s disease and HIV can cause depression, mostly because of the physical weakness and stress associated with the diseases. Because depression weakens the immune system, it can make pain harder to bear. 
• Other Psychological Disorders: Mood disorders, anxiety, eating disorders and substance abuse are often present with depression.

Symptoms of Depression

Not all people with depression have the same symptoms. Some people might have just a few. Others may have a lot. If you have one or more of the following symptoms for more than two weeks or months at a time, see your doctor or practitioner.

• Feeling sad, anxious, or empty;
• Feeling hopeless;
• Loss of interest in hobbies and activities that you once enjoyed;
• Decreased energy;
• Difficulty staying focused, remembering, making decisions;
• Sleeplessness, early morning awakening, or oversleeping and not wanting to get up;
• No desire to eat and weight loss or eating to “feel better” and weight gain;
• Thoughts of hurting yourself;
• Thoughts of death or suicide;
• Easily annoyed, bothered or angered;
• Constant physical symptoms that do not get better with treatment, such as headaches, upset stomach, and pain that doesn’t go away.

Sources: Depression.com; National Institute of Mental Health; National Alliance for Research on Schizophrenia and Depression; “Depression: Frequently Asked Questions,” National Women’s Health Information Center, U.S. Dept. of Health and Human Services.