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Understanding Depression -- the Basics

What Is Depression?

Almost all of us feel low sometimes, usually because of a disturbing or difficult event in our lives. But ongoing sadness or despair can be caused by depression, a serious condition that warrants treatment. 

Depression affects 20% of all women, 10% of all men, and 5% of all adolescents worldwide. It is ranked as the fourth greatest cause of global illness burden by the World Health Organization and is the second most common psychiatric problem in the U.S. (after anxiety disorders), afflicting about 17.6 million people each year at a cost in the range of about $50 billion a year. 

Understanding Depression

Find out more about depression:



Diagnosis and Treatment


Depression can strike at any age, including in childhood. Studies in the U.S. show that in 2008, between 7.4% and 8.7% of adults (18-49) and 8.3% of adolescents (12-17) had a major depressive episode during the previous year. However, most people first experience depression when they are in their early thirties, and depression is particularly rife among older adults. Depression is not simply a normal reaction to the challenges of growing older, such as the death of a spouse or friends and the physical limitations of age, but is a medical condition without a known cause. 

Furthermore, about 10%-20% of women experience postpartum depression after giving birth. In these cases, symptoms may last from weeks to years. With professional help, almost all women who experience postpartum depression are able to overcome their symptoms.

What Are the Different Types of Depression?

  • Depressive reaction. A less-severe and often temporary depression that arises from a specific life situation. Depressive reaction is also called an adjustment disorder with depressed mood. The symptoms can be severe, but unless they involve additional symptoms such as changes in sleep and appetite or thoughts of suicide, they usually do not need treatment and will abate over time -- anywhere from two weeks to six months.
  • Dysthymia . A low-grade, long-term depression that lasts for more than one year for children and adolescents and at least two years for adults. Dysthymia is similar to depressive reaction in its symptoms and degree of suffering; however, it lasts longer and may become a chronic condition. Over the course of a lifetime, over 11% of teens (13-18) suffer from dysthymia, according to the National Institute of Mental Health.
  • Major depression. A serious condition that can lead to an inability to function or suicide. Sufferers experience not only a depressed mood, but also have difficulty performing simple daily tasks, lose interest in their usual activities, extreme fatigue, sleep problems, or feelings of guilt and helplessness. They can sometimes also lose touch with reality, having delusions (such as believing they have committed a sin, or are dying) or hallucinations (such as hearing an imaginary voice telling them they are no good), in severe cases. It can be a cyclical illness, so while most patients recover from their first depressive episode, the recurrence rate is high -- perhaps as high as 60% within two years and 75% within 10 years. After 15 years, 90% of individuals will have suffered a recurrence or relapse of depression.

Major depression, which affects more than 16% of U.S. adults over a lifetime, often appears spontaneously and is seemingly unprovoked, or it can begin as a depressive reaction following a loss, trauma, or other significant stressful event. Then the reaction can intensify and evolve into a full-blown depressive episode. The depressive episode may also disappear spontaneously, usually within six to 12 months, although treatment is often needed to achieve full control of symptoms. Because of its disabling effects and the possibility of suicide, major depression requires medical treatment.


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