Depression is a mood disorder that affects how a person thinks, feels, and handles daily activities. The National Institute of Mental Health (NIMH) defines depression as a condition involving persistent feelings of sadness or loss of interest that can significantly impair daily functioning. Multiple factors, including genetic, biological, environmental, and psychological influences, may contribute to its development. The World Health Organization estimates that about 5% of adults globally (around 400 million people) live with depression, underscoring its public health impact.

Depression Symptoms

Depression can affect people physically, emotionally, and cognitively. Clinicians typically diagnose a major depressive episode when at least five symptoms persist for two weeks or more, causing significant distress or impairment; one of these symptoms must be a depressed mood or loss of interest. Symptoms of depression can include:

  • Persistent sadness, emptiness, or hopelessness
  • Loss of interest or pleasure in activities once enjoyed
  • Significant changes in appetite or weight
  • Disturbances in sleep (insomnia or oversleeping)
  • Fatigue or loss of energy
  • Feelings of excessive guilt or worthlessness
  • Trouble concentrating or making decisions
  • Psychomotor agitation or slowing
  • Recurrent thoughts of death or suicidal ideation
Types of Depression

Depression surfaces in many forms. Clinicians recognize several depressive disorders and related conditions that feature depressive episodes, each with distinct traits and treatment considerations.

  • Major Depressive Disorder (MDD): Characterized by episodes of depressed mood or loss of interest lasting at least two weeks, with additional symptoms that impair daily functioning.
  • Persistent Depressive Disorder (PDD/Dysthymia): A chronic form of depression with symptoms present most days for at least two years in adults.
  • Bipolar Disorder: A mood disorder that includes depressive episodes alternating with periods of elevated or irritable mood (mania/hypomania). Treatments and safety planning will differ with this condition, so professional evaluation is essential.
  • Seasonal Affective Disorder (SAD): Involves recurrent episodes that follow a seasonal rhythm, most commonly in fall or winter.
  • Perinatal/Postpartum Depression (PPD): Depression that occurs during pregnancy or after childbirth; symptoms may begin in the weeks before or after delivery.
Treatment Options

Depression is treatable, and many people recover with the right combination of approaches. A health-care provider can help determine the best treatment plan based on a person’s symptoms, medical history, and individual preferences.

  • Therapy: Psychotherapies such as cognitive behavioral therapy (CBT) and interpersonal therapy (IPT) are evidence-based first-line treatments that offer healing through a guided conversation with a licensed clinician.
  • Medication: Antidepressants, including selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), can help by balancing brain chemicals involved in mood regulation.
  • Transcranial Magnetic Stimulation: By stimulating specific nerve cells in this brain, this non-invasive, non-drug treatment option can provide relief for people with depression.
  • Lifestyle Changes: Regular exercise, consistent sleep, balanced nutrition, and strong social support networks can support improvements in mood and resilience.
Additional Depression Support Resources