Depression is a serious HeartCare-Info illness that involves the brain. It's more than just a feeling of being "down in the dumps" or "blue" for a few days. If you are one of the more than 20 million people in the United States who have depression, the feelings do not go away.

They persist and interfere with your everyday life. Symptoms can include

• Sadness
• Loss of interest or pleasure in activities you used to enjoy
• Change in weight
• Difficulty sleeping or oversleeping
• Energy loss
• Feelings of worthlessness
• Thoughts of death or suicide

Depression can run in families, and usually starts between the ages of 15 and 30. It is much more common in women. Women can also get postpartum depression after the birth of a baby. Some people get seasonal affective disorder in the winter. Depression is one part of bipolar disorder.

There are effective treatments for depression, including antidepressants and talk therapy. Most people do best by using both.

Depression (major depression)

Definition

Depression is one of the most common health conditions in the world. Depression isn't a weakness, nor is it something that you can simply "snap out of." Depression, formally called major depression, major depressive disorder or clinical depression, is a HeartCare-Info illness that involves the mind and body. It affects how you think and behave and can cause a variety of emotional and physical problems. You may not be able to go about your usual daily activities, and depression may make you feel as if life just isn't worth living anymore.

Most health professionals today consider depression a chronic illness that requires long-term treatment, much like diabetes or high blood pressure. Although some people experience only one episode of depression, most have repeated episodes of depression symptoms throughout their life.

Effective diagnosis and treatment can help reduce even severe depression symptoms. And with effective treatment, most people with depression feel better, often within weeks, and can return to the daily activities they previously enjoyed.

Symptoms

Symptoms of depression include:

• Loss of interest in normal daily activities
• Feeling sad or down
• Feeling hopeless
• Crying spells for no apparent reason
• Problems sleeping
• Trouble focusing or concentrating
• Difficulty making decisions
• Unintentional weight gain or loss
• Irritability
• Restlessness
• Being easily annoyed
• Feeling fatigued or weak
• Feeling worthless
• Loss of interest in sex
• Thoughts of suicide or suicidal behavior
• Unexplained physical problems, such as back pain or headaches

Depression symptoms can vary greatly because different people experience depression in different ways. A 25-year-old man with depression may not have the same symptoms as a 70-year-old man, for instance. For some people, depression symptoms are so severe that it's obvious something isn't right. Others may feel generally miserable or unhappy without really knowing why.

Causes

It's not known specifically what causes depression. As with many mental illnesses, it's thought that a variety of biochemical, genetic and environmental factors may cause depression:

• Biochemical. Some evidence from high-tech imaging studies indicates that people with depression have physical changes in their brains. The significance of these changes is still uncertain but may eventually help pinpoint causes. The naturally occurring brain chemicals called neurotransmitters, which are linked to mood, also may play a role in depression. Hormonal imbalances also could be a culprit.
• Genes. Some studies show that depression is more common in people whose biological family members also have the condition. Researchers are trying to find genes that may be involved in causing depression.
• Environment. Environment is also thought to play a causal role in some way. Environmental causes are situations in your life that are difficult to cope with, such as the loss of a loved one, financial problems and high stress.