Depression (major depressive disorder)

Major depressive disorder (commonly called depression) is a common and serious mood disorder that negatively affects how you feel, think, and handle daily activities. It is more than ordinary sadness or a temporary case of the “blues.” Depression causes persistent feelings of sadness, emptiness, or irritability accompanied by physical and cognitive changes that significantly impair functioning.

Depression can occur at any age, but it often first appears in the late teens to mid-20s. It is treatable. Most people with depression improve with medication, psychotherapy, or both. Early recognition and treatment improve outcomes and reduce the risk of complications, including suicide.

For a diagnosis of major depressive disorder, symptoms must be present most of the day, nearly every day, for at least two weeks and represent a change from previous functioning. Core symptoms include:

• Persistent sad, empty, or hopeless mood
• Loss of interest or pleasure in almost all activities (anhedonia)
• Significant weight loss or gain, or decrease/increase in appetite
• Insomnia or hypersomnia
• Psychomotor agitation or retardation (observable by others)
• Fatigue or loss of energy
• Feelings of worthlessness or excessive guilt
• Diminished ability to think, concentrate, or make decisions
• Recurrent thoughts of death, suicidal ideation, or suicide attempt

Symptoms can also include physical aches and pains without clear cause, irritability (especially in men and adolescents), and withdrawal from social activities. Severity ranges from mild to severe.

Depression results from a complex interaction of biological, psychological, and social factors:

• Biological — Differences in brain chemistry, structure, and function; hormonal changes; genetic predisposition
• Psychological — Personality traits (e.g., high neuroticism), cognitive styles that emphasize negative interpretations, history of trauma or abuse
• Environmental / social — Major life stressors (loss, financial hardship, relationship problems), chronic medical illness, social isolation, substance use

No single cause explains every case. Depression often runs in families, but many people with a family history never develop it, and many people without a family history do.

Factors that increase the risk of depression include:

• Personal or family history of depression or bipolar disorder
• Major life changes, trauma, or stress
• Certain personality traits
• Physical illness or chronic pain
• Certain medications
• Substance use disorders
• Female sex (depression is diagnosed more often in women)
• History of other mental-health disorders (anxiety, eating disorders, PTSD)

Untreated or inadequately treated depression can lead to:

• Suicide or self-harm
• Relationship and family problems
• Difficulties at work or school and financial hardship
• Social isolation
• Substance misuse
• Worsening of chronic medical conditions (heart disease, diabetes, chronic pain)
• Obesity or weight-related health problems
• Physical pain and other somatic symptoms

There is no guaranteed way to prevent depression, but the following strategies may help reduce risk or severity of episodes:

• Seek treatment at the earliest sign of symptoms
• Build strong social support networks
• Develop healthy stress-management and coping skills
• Stay physically active and maintain regular sleep routines
• Limit alcohol and avoid recreational drugs
• Treat related conditions such as anxiety or chronic pain
• Consider maintenance treatment if you have had multiple previous episodes

Diagnosis is clinical and based on a thorough interview covering symptoms, duration, impact on functioning, medical history, family history, and possible contributing factors. Standardized questionnaires (PHQ-9, etc.) are often used to assess severity and monitor progress.

Physical examination and laboratory tests may be ordered to rule out medical conditions that can mimic or contribute to depression (thyroid disorders, vitamin deficiencies, anemia, etc.). There is no laboratory test that diagnoses depression itself.

See a healthcare professional if you experience symptoms of depression that last more than two weeks and interfere with work, relationships, or daily functioning. Seek help sooner if symptoms are severe.

If you or someone you know is having thoughts of suicide or self-harm, get help immediately:

• Call or text 988 (Suicide & Crisis Lifeline in the United States)
• Go to the nearest emergency room
• Contact a local crisis line or mental-health crisis team

Depression is a medical illness, not a personal failing. Effective help is available.

Effective treatments include:

• Psychotherapy — Cognitive-behavioral therapy (CBT), interpersonal therapy (IPT), behavioral activation, and other evidence-based approaches. Therapy can be individual, group, or family-based.
• Medications — Selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), atypical antidepressants, and other classes. Finding the right medicine and dose often takes time and collaboration with a clinician.
• Combination treatment — Medication plus psychotherapy is often more effective than either alone for moderate to severe depression.
• Brain-stimulation therapies — Electroconvulsive therapy (ECT), transcranial magnetic stimulation (TMS), and other modalities for treatment-resistant depression.
• Lifestyle measures — Regular exercise, healthy sleep, nutrition, and social connection support recovery.

Treatment plans are individualized and adjusted according to response and side effects.

While professional treatment is usually necessary, self-care practices support recovery:

• Stick with the treatment plan even after you start feeling better
• Learn about depression so you can recognize early warning signs of relapse
• Exercise regularly if possible
• Maintain a consistent sleep schedule
• Eat regular, nutritious meals
• Avoid alcohol and recreational drugs
• Stay connected with supportive people
• Break large tasks into smaller steps and set realistic goals
• Practice stress-reduction techniques (mindfulness, breathing exercises, time in nature)

To make the visit more productive:

• Write down your symptoms, when they started, and how they affect your daily life
• Note major stressors or life changes
• List all medicines, supplements, and recreational substances
• Bring a family member or friend if you feel comfortable
• Prepare questions about treatment options, expected timeline, side effects, and what to do if you have thoughts of self-harm
• Be honest about the severity of symptoms, including any suicidal thoughts—this information is essential for safe care