Major Depression (Major Depressive Disorder)

Overview

Major depression, also called major depressive disorder (MDD) or clinical depression, is a common but serious mood disorder. It is more than a temporary low mood or a reaction to a difficult event. It involves persistent feelings of sadness or loss of interest along with other symptoms that affect how a person thinks, feels, and handles daily activities such as sleeping, eating, and working.

Depression is a real medical illness, not a sign of weakness or something a person can simply will away. It can affect anyone at any age. Importantly, it is highly treatable, and most people improve with the right combination of therapy, medication, and support.

Symptoms

A diagnosis of major depression generally requires several symptoms present most of the day, nearly every day, for at least two weeks, including either persistent low mood or loss of interest. Symptoms include:

• Persistent sad, anxious, or empty mood
• Loss of interest or pleasure in activities once enjoyed
• Fatigue or low energy
• Changes in appetite or weight
• Sleeping too much or too little
• Difficulty concentrating, remembering, or making decisions
• Feelings of worthlessness or excessive guilt
• Restlessness or slowed movements
• Thoughts of death or suicide

If you or someone you know is having thoughts of suicide, seek help immediately by contacting a suicide and crisis lifeline or emergency services.

Causes

Depression usually results from a combination of factors rather than a single cause:

• Biological factors: Differences in brain chemistry and function, and changes in hormones.
• Genetics: Depression often runs in families.
• Life events and stress: Loss, trauma, abuse, chronic stress, or major life changes.
• Medical conditions and medications: Some illnesses and drugs can contribute.

These factors interact differently for each person, which is why depression looks different from one individual to another.

Risk Factors

• A personal or family history of depression or other mental health conditions
• Major life stress, trauma, or loss
• Chronic medical illness or chronic pain
• Certain medications
• Substance use
• Social isolation or lack of support

Diagnosis

A doctor or mental health professional diagnoses major depression through a clinical interview about mood, thoughts, behavior, sleep, appetite, and daily functioning. There is no blood test for depression, but a doctor may order tests to rule out medical causes such as thyroid problems or anemia.

Standardized questionnaires are often used to assess severity and track progress. A careful evaluation also screens for thoughts of self-harm and for other conditions, such as bipolar disorder, that change the treatment approach.

Treatment

Major depression is highly treatable, and many people benefit from a combination of approaches:

• Psychotherapy: Talk therapies such as cognitive behavioral therapy (CBT) and interpersonal therapy help change unhelpful thoughts and build coping skills.
• Medication: Antidepressants can help correct chemical imbalances; finding the right one may take some adjustment and several weeks to work fully.
• Lifestyle support: Regular physical activity, good sleep habits, social connection, and reducing alcohol can support recovery.
• Other treatments: For severe or treatment-resistant depression, options such as brain stimulation therapies may be considered.

It is important to continue treatment as advised and not stop medication suddenly without medical guidance.

Prevention

Depression cannot always be prevented, but some strategies may reduce risk or recurrence:

• Stay connected with supportive people
• Manage stress and seek help early during difficult times
• Maintain regular sleep, activity, and balanced routines
• Continue treatment and follow-up if you have had depression before
• Limit alcohol and avoid recreational drugs

When to See a Doctor

See a doctor or mental health professional if low mood, loss of interest, or other symptoms last more than two weeks or interfere with daily life. Depression improves with treatment, and seeking help early leads to better outcomes.

Seek emergency help immediately if you have thoughts of harming yourself or suicide. Contact local emergency services or a suicide and crisis lifeline right away. You do not have to face these feelings alone, and help is available.

Related Topics

Frequently Asked Questions

References

1. National Institute of Mental Health (NIMH). Depression.
2. Mayo Clinic. Depression (major depressive disorder).
3. MedlinePlus, U.S. National Library of Medicine. Depression.
4. World Health Organization (WHO). Depressive disorder.