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Depression · Condition Guide

Major Depressive Disorder

Depression is one of the most treatable conditions in mental health. Here's what the evidence shows.

Medically reviewed by Dr. Sarah Chen, Psy.D · Last reviewed: May 2026 · Editorial standards
Major DepressionMDDDepression TreatmentAntidepressantsCBT for Depression

Understanding major depression

Major Depressive Disorder (MDD) involves persistent depressed mood or loss of interest or pleasure, accompanied by other symptoms — changes in sleep, appetite, energy, concentration, and in severe cases, suicidal thoughts — occurring most of the day, nearly every day, for at least two weeks. It is one of the most common conditions in mental health, affecting approximately 21 million US adults annually.

Depression is not sadness or weakness. It is a medical condition with neurobiological underpinnings that responds to evidence-based treatment. Telling someone with depression to "try harder" or "think positive" is like telling someone with a broken leg to walk it off.

Recognizing depression beyond sadness

The stereotypical depressed person is visibly sad, tearful, and self-pitying. Many people with depression present differently: irritability, emptiness, loss of motivation, cognitive slowing, physical fatigue, social withdrawal, or increased focus on physical complaints. Men in particular are more likely to present with irritability and risk-taking than visible sadness.

What works: the evidence base

CBT has the most extensive evidence base for depression and produces effects equivalent to antidepressants with lower relapse rates. Behavioral Activation — increasing engagement with rewarding activities — is a core component and effective as a standalone treatment. Antidepressants (SSRIs, SNRIs) are effective for moderate to severe depression and are often combined with therapy for the best outcomes. Exercise has evidence comparable to antidepressants for mild to moderate depression.

Depression significantly impairs motivation — creating a cruel paradox where the treatment (getting help, doing therapy, exercising) requires energy that depression removes. Starting small matters: a single session with a therapist, a 10-minute walk, one social contact. Behavioral activation specifically addresses this by starting with low-threshold pleasant activities.

Frequently asked questions
Most people with a single depressive episode achieve remission within 2-3 months of effective treatment. However, depression has a high recurrence rate — approximately 50% after a first episode, 80% after a second. Many clinicians recommend continuing antidepressants for at least 6-12 months after remission to prevent relapse, and considering maintenance treatment for people with recurrent depression.
Seek emergency help if you are having active suicidal thoughts with a plan or intent, if you have access to means of suicide, or if you are unable to care for yourself. Call 988 (Suicide and Crisis Lifeline), go to your nearest emergency room, or call 911. You can also text 988.
In crisis?Tap to call 988