Overview
Depression is a common but serious mood disorder that affects how a person feels, thinks, and handles daily activities. It goes beyond occasional sadness—people with depression experience persistent feelings of hopelessness, emptiness, or a lack of interest in things they once enjoyed. Depression can affect both mental and physical health.

Why It’s Important
If left untreated, depression can interfere with work, relationships, and overall well-being. It’s a leading cause of disability worldwide and can increase the risk of suicide. The condition is treatable, but many people go undiagnosed or don’t seek help.

Quick Facts

• Affects over 280 million people worldwide (WHO)

• Can occur at any age, but often begins in the late teens to early 30s

• Women are more likely to experience depression than men

• Can be short-term (situational) or long-lasting (major depressive disorder)

• Often co-occurs with anxiety disorders, substance use, or chronic illness

What Happens in the Body
Depression involves chemical imbalances in the brain, particularly with neurotransmitters like serotonin, dopamine, and norepinephrine. These changes affect the brain’s mood regulation systems and can alter sleep, appetite, energy levels, and cognition. Genetics, hormones, and stress all contribute to its development.

Common Signs and Symptoms

• Persistent sadness or low mood

• Loss of interest or pleasure in activities

• Fatigue or low energy

• Changes in appetite or weight

• Sleep problems (too much or too little)

• Feelings of worthlessness or excessive guilt

• Trouble concentrating or making decisions

• Irritability or restlessness

• Physical symptoms (headaches, digestive issues, chronic pain)

• Thoughts of death or suicide

Diagnosis

• Clinical interview by a mental health professional

• Standardized screening tools (e.g., PHQ-9 questionnaire)

• Diagnosis typically requires symptoms lasting at least two weeks

• Medical tests may be done to rule out conditions like thyroid issues or vitamin deficiencies

• See a doctor if symptoms are persistent, severe, or interfere with daily life

Treatment and Management

• Psychotherapy (talk therapy):

  • Cognitive Behavioral Therapy (CBT)

  • Interpersonal therapy

  • Behavioral activation

• Medications:

  • Antidepressants (e.g., SSRIs like fluoxetine or sertraline, SNRIs, tricyclics)

  • May take several weeks to work, and dosage may need adjusting

• Lifestyle changes:

  • Regular exercise, balanced diet, sleep hygiene

  • Social support and stress reduction

• Other treatments:

  • Electroconvulsive therapy (ECT) for severe or treatment-resistant depression

  • Transcranial magnetic stimulation (TMS)

  • Light therapy (for seasonal depression)

• Most people improve with proper treatment, though it may require ongoing care

Risks and Complications

• Can lead to social isolation, job loss, and strained relationships

• Increases risk of chronic illnesses (e.g., heart disease, diabetes)

• Can worsen outcomes in other medical conditions

• Suicidal thoughts or actions—this is a medical emergency

Who Is at Risk

• Family history of depression or mental illness

• Chronic stress or recent trauma (e.g., loss, abuse, financial hardship)

• Medical conditions (e.g., chronic pain, cancer, diabetes)

• Substance use disorders

• Major life changes (e.g., childbirth, retirement)

• People with low social support or exposure to discrimination or violence

Related Conditions

• Anxiety disorders

• Bipolar disorder (must be ruled out before prescribing antidepressants)

• Postpartum depression

• Seasonal Affective Disorder (SAD)

• Persistent depressive disorder (dysthymia)

• Premenstrual dysphoric disorder (PMDD)

When to See a Doctor

• If symptoms last more than two weeks or worsen over time

• If you notice loss of interest, changes in sleep or appetite, or feelings of hopelessness

• If you have thoughts of self-harm or suicide—seek help immediately

• Early treatment can lead to better outcomes and prevent long-term effects

Last Updated: June 21, 2025