What is depression?

Major depression is a mood state that goes well beyond temporarily feeling sad or blue. It is a serious medical illness that affects one’s thoughts, feelings, behavior, mood and physical health. Depression is a life-long condition in which periods of wellness alternate with recurrences of illness.

Each year depression affects 5-8 percent of adults in the United States. This means that about 25 million Americans will have an episode of major depression this year alone. Depression occurs 70 percent more frequently in women than in men for reasons that are not fully understood. Without treatment, the frequency and severity of these symptoms tend to increase over time.

For more information on depression in women, visit NAMI’s Women and Depression section.

Major depression is also known as clinical depression, major depressive illness, major affective disorder and unipolar mood disorder. It involves some combination of the following symptoms: depressed mood (sadness), poor concentration, insomnia, fatigue, appetite disturbances, excessive guilt and thoughts of suicide. Left untreated, depression can lead to serious impairment in daily functioning and even suicide, which is the 10th leading cause of death in the U.S. Researchers believe that more than one-half of people who die by suicide are experiencing depression. Devastating as this disease may be, it is treatable in most people. The availability of effective treatments and a better understanding of the biological basis for depression may lessen the barriers that can prevent early detection, accurate diagnosis and the decision to seek medical treatment.

Getting an accurate diagnosis is important. First, rule out other possible medical conditions that mimic depression, such as hypothyroidism (underactive thyroid), complications from substance abuse or dependence, infectious diseases, anemia and certain neurological disorders. Understanding the psychiatric context-including the risk of bipolar disorder and the assessment of safety risk-is also an essential aspect of an evaluation.

Who’s at risk?

All age groups and all racial, ethnic and socioeconomic groups can experience depression.

  • Men
  • Women
  • Veterans
  • Cultural Groups
  • GLBT
  • Children and Adolescents
  • Seniors

Download the NAMI depression fact sheet.