Major Depressive Disorder

Posted byRatel Health
Evidence-based mental health content, reviewed by psychologists and psychiatrists
Attention-Deficit/Hyperactivity Disorder (ADHD)Autism Spectrum DisorderBipolar I DisorderObsessive-Compulsive DisorderPost-Traumatic Stress Disorder

Major Depressive Disorder

Medically reviewed · Ratel Health editorial team · Sunday, 16 August 2026

A mood disorder involving persistent sadness or loss of interest that interferes with daily life for at least two weeks.

Overview

Major depressive disorder (MDD) is a common and treatable mood disorder characterized by persistent sadness or loss of interest that interferes with daily functioning for at least two weeks.

Signs and Symptoms

Symptoms may include depressed mood most of the day, markedly diminished interest in activities, changes in appetite or weight, sleep disturbance, fatigue, feelings of worthlessness or excessive guilt, difficulty concentrating, and recurrent thoughts of death. Experiencing one or more of these symptoms does not necessarily mean that a person has this condition. Diagnosis requires an appropriate clinical evaluation.

Causes and Risk Factors

The exact cause is not fully understood. Genetic factors, changes in brain chemistry and structure, chronic stress, and significant life events are each associated with increased risk, though none of these alone fully explains why depression develops in a given individual.

Diagnosis

A diagnosis should be made by a qualified healthcare professional following a comprehensive clinical assessment. Clinicians may use established diagnostic frameworks such as DSM-5-TR as part of a comprehensive assessment.

Treatment

Treatment depends on the individual's symptoms, clinical history, severity, age, co-occurring conditions, and other relevant factors.

Psychotherapy

Cognitive behavioral therapy and interpersonal therapy have evidence supporting their use and may help reduce depressive symptoms.

Medication

Antidepressant medications may be recommended by a prescribing clinician for moderate to severe symptoms. Medication decisions should be made with a qualified prescribing healthcare professional. Do not start, stop, or change a prescribed medication based solely on information on this page.

Living With Major Depressive Disorder

Maintaining a consistent routine, staying connected with supportive people, monitoring symptoms, and following up with a treatment provider can support day-to-day functioning.

When to Seek Professional Help

Professional evaluation may be appropriate if symptoms persist, worsen, cause significant distress, or interfere with work, school, or relationships.

Emergency Situations

If a person may be in immediate danger, is experiencing a medical or psychiatric emergency, or may harm themselves or another person, seek immediate assistance through appropriate local emergency services.

Outlook

Outcomes vary depending on severity, individual circumstances, access to appropriate care, co-occurring conditions, and response to treatment.

Related Conditions

Persistent Depressive Disorder

A chronic depressive condition involving a depressed mood that occurs for most of the day, for more days than not, for at least two years.

Generalized Anxiety Disorder

A persistent pattern of excessive, difficult-to-control worry about everyday events and activities.

Bipolar I Disorder

A mood disorder defined by at least one manic episode, often accompanied by episodes of depression.

Seasonal Affective Disorder (Seasonal Pattern)

A pattern of recurrent major depressive episodes that occur at a specific time of year, most commonly during fall and winter months.

Postpartum Depression

A depressive episode that occurs during pregnancy or in the weeks to months following childbirth.

Medical Information Disclaimer

Ratel Health provides general educational information and does not provide medical diagnosis, treatment, or individualized medical advice. Information on this page is not a substitute for evaluation or care from a qualified healthcare professional. Do not use this information to diagnose yourself or another person, or to start, stop, or change treatment or medication without consulting an appropriately qualified healthcare professional.

References

  • American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR).
  • National Institute of Mental Health.
  • World Health Organization. International Classification of Diseases, 11th Revision.