NAMI HelpLine

 

Feelings of sadness are common human emotions. When more severe symptoms like lack of energy and hopelessness develop in multiple areas of a person’s life along with persistent sadness over at least two weeks, they may be experiencing a condition known as major depressive disorder (MDD). MDD is sometimes also referred to as clinical depression. Fortunately, with early identification, diagnosis and a treatment plan that can include a combination of medication, psychotherapy and healthy lifestyle choices, many people with depression can and do get better.

Some will only experience one depressive episode in their lifetime, but for most, the episodes recur. Without treatment, episodes may last a few months to several years.

About 15.5% of U.S. adults experience major depressive disorder in a given year. People of all ages and all racial, ethnic and socioeconomic backgrounds experience depression, but it does appear to be more prevalent in some groups than others.

Causes

Depression does not have a single cause. Symptoms can begin to appear following a life crisis, physical illness or something else—but they can also occur for no reason at all. Researchers have identified several factors that can contribute to depression:

  • Trauma. When people experience trauma at an early age, it can cause changes in how our brains respond to fear and stress. These changes may lead to depression.
  • Genetics. Mood disorders, such as depression, tend to run in families.
  • Life circumstances. Changes in relationships, financial status, living situation and loss of loved ones can influence whether someone develops symptoms of depression.
  • Brain changes. There is still much that we don’t know, but imaging studies have shown that the frontal lobe of the brain becomes less active when a person is depressed. Depression is also associated with changes in how the pituitary gland and hypothalamus respond to hormone stimulation.
  • Other medical conditions. People who have a history of sleep disturbances, medical illness, chronic pain, anxiety and attention-deficit hyperactivity disorder (ADHD) are more likely to develop depression. Some medical syndromes (like hypothyroidism) can mimic depressive disorder. Some medications can also cause symptoms of depression.
  • Drug and alcohol misuse. Adults with a substance use disorder are at significantly higher risk for experiencing a major depressive episode. Co-occurring disorders require coordinated treatment for both conditions, as alcohol can worsen depressive symptoms.

Personal Perspectives on Major Depressive Disorder

In this 2-part podcast series, NAMI Chief Medical Officer Dr. Ken Duckworth guides discussions on major depressive disorder that offer insights from individuals, family members and mental health professionals. Read the transcript.
Note: Content includes discussions on topics such as suicide attempts and may be triggering.

 

Reviewed and updated June 2025

NAMI HelpLine is available M-F, 10 a.m. – 10 p.m. ET. Call 800-950-6264,
text “NAMI” to 62640, or email. In a crisis, call or text 988 (24/7).