What is Depression?

Depression is a common but serious illness.

Around one in every 10 people will suffer from depression. Everyone occasionally feels blue or sad. But these feelings are usually short-lived and pass within a couple of days.

When you have depression, it interferes with daily life and causes pain for both you and those who care about you.

Many people with a depressive illness never seek treatment. But the majority, even those with the most severe depression, can get better with treatment. Medications, psychotherapies and other methods can effectively treat people with depression.

What causes depression?

Most likely, depression is caused by a combination of genetic, biological, environmental and psychological factors. Depressive illnesses are disorders of the brain.

Brain regions that control mood are often disrupted in depression. By understanding the brain better, our ability to treat depression should also get a boost.

Watch the video to learn about the neural circuits affected by depression and the molecular and cellular changes that might hold the key to treating it.

Created by the editors at Nature Neuroscience.

There are several forms of depressive disorders.

Major Depression

Severe symptoms that interfere with your ability to work, sleep, study, eat and enjoy life. An episode may occur only once in a person’s lifetime, but more often, a person has several episodes.

Persistent Depressive Disorder

A depressed mood that lasts for at least two years. A person diagnosed with persistent depressive disorder may have episodes of major depression along with periods of less severe symptoms, but symptoms must last for two years.

Varying forms of depression include:

Psychotic depression, which occurs when a person has severe depression plus some form of psychosis, such as having disturbing false beliefs or a break with reality (delusions), or hearing or seeing upsetting things that others cannot hear or see (hallucinations).

Postpartum depression, which is much more serious than the “baby blues” that many women experience after giving birth when hormonal and physical changes and the new responsibility of caring for a newborn can be overwhelming. It is estimated that 10 to 15 percent of women experience postpartum depression after giving birth.

Seasonal affective disorder (SAD), which is characterized by the onset of depression during the winter months, when there is less natural sunlight. The depression generally lifts during spring and summer. SAD may be effectively treated with light therapy, but nearly half of those with SAD do not get better with light therapy alone. Antidepressant medication and psychotherapy can reduce SAD symptoms, either alone or in combination with light therapy.

Bipolar disorder, also called manic-depressive illness, is not as common as major depression or persistent depressive disorder. Bipolar disorder is characterized by cycling mood changes—from extreme highs (e.g., mania) to extreme lows (e.g., depression).

The ThriveLogic team has organized important research on depression. 

Explore Depression Facts & Stats

The Burden of Mental Illness

  • According to the World Health Organization, unipolar depression was the third most important cause of disease burden worldwide in 2004. Unipolar depression was in “eighth place in low-income countries but at first place in middle- and high-income countries.”
  • In a nationally representative face-to-face household survey, 6.7% of U.S. adults experienced a major depressive episode in the past 12 months.
  • Significantly greater percentages of lifetime major depression have been reported among women (11.7%) than men (5.6%).
  • Examining ethnic differences reveals lifetime percentages of depression of 6.52% among whites and 4.57% among blacks and 5.17% among Hispanics.

The Stigma of Mental Illness

In 2007, the Behavioral Risk Factor Surveillance System (BRFSS) surveyed adults in 37 states and territories about their attitudes toward mental illness, using the 2007 BRFSS Mental Illness and Stigma Module.

Based on 2007 BRFSS data:

  • Most adults with mental health symptoms (78%) and without mental health symptoms (89%) agreed that treatment could help persons with mental illness lead normal lives.
  • 57% of all adults believed that people are caring and sympathetic to persons with mental illness.
  • Only 25% of adults with mental health symptoms believed that people are caring and sympathetic to persons with mental illness.

These findings highlight both the need to educate the public about how to support persons with mental illness and the need to reduce barriers for those seeking or receiving treatment for mental illness.

Data from the National Health and Nutrition Examination Survey

  • In any 2-week period, 5.4% of Americans 12 years of age and older experienced depression. Rates were higher in 40-59-year-olds, women, and non-Hispanic black persons than in other demographic groups.
  • Rates of depression were higher among poor persons than among those with higher incomes.
  • Approximately 80% of persons with depression reported some level of functional impairment because of their depression, and 27% reported serious difficulties in work and home life.
  • Only 29% of all persons with depression reported contacting a mental health professional in the past year, and among the subset with severe depression, only 39% reported contact.
CDC stats

County-Level Prevalence of Frequent Mental Distress Among U.S. Adults 2003-2009 Source: Centers For Disease Control