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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 depression €” suffering a period of what is known as major depression €” is another matter. Depression in some form 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 most common psychological problem in the U.S., afflicting about 17.6 million people each year at a cost in the range of about 50 billion dollars a year.

Depressive reaction (minor and often temporary depression) encompasses the normal depressed feelings that arise because of a specific life situation. Depressive reaction is also called an adjustment disorder with depressed mood. The symptoms can be severe, but they usually do not need treatment and will abate over time -- anywhere from two weeks to six months.

Dysthymia (minor, long-term depression for more than one year (for children and adolescents) to two years (for adults)) is similar to depressive reaction in its symptoms and degree of suffering; however, it lasts longer -- at least two years, and may become a chronic condition.

Major depression is a serious condition that can lead to an inability to function or even to suicide. Sufferers experience not only a depressed mood but also more harmful symptoms, including difficulty performing simple daily tasks, disinterest in their usual activities, extreme fatigue, sleep problems, or feelings of guilt and helplessness. They are more likely to lose touch with reality, sometimes having delusions or hallucinations in severe cases. It is a cyclical illness, so though 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. Major depression 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, though treatment is often needed to achieve full control of symptoms. Because of its disabling effects and the possibility of suicide, major depression needs treatment.

Depression can strike at any age, including in childhood. Studies in the U.S. show that 1.8% of prepubertal children and 4.7% of 14- to 17-year-olds have some form of depression. However, the common time of onset is early middle age, and depression is particularly rife among the elderly, as a reaction to the facts of growing older -- the death of a spouse or friends, the physical limitations of age and the impending confrontation with death. Elderly widowers are particularly susceptible to suicide.

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 Causes It?

Depression is an illness that seems to have different causes. Depressive reaction, or "normal depression," occurs as a result of a particular event. Depressed moods can also be a side effect of medication, hormonal changes (such as before menstrual periods or after childbirth), or a physical illness, such as the flu or a viral infection.

Although the exact causes of major depression and dysthymia are unknown, researchers currently believe that both forms are caused by a malfunction of the brain's neurotransmitters, chemicals that modulate moods. The neurotransmitters thought to be involved in mood regulation include serotonin, norepinephrine, and possibly dopamine. This malfunction seems to have a large genetic component: In one study, 27% of depressed children had close relatives who suffered from mood disorders.

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