Reference
Depression glossary
A short reference for words that come up in depression care. Definitions are plain language, not textbook. Each entry has its own page with a longer explanation, related terms, and related articles.
How to use this glossary
The glossary is built for two kinds of moments. The first is the moment a person reads a clinical word for the first time and wants a clear definition. The second is the moment a clinician uses a word in a visit and the patient wants to look it up later without having to find the exact phrase in the medical record. Each entry begins with a one-sentence quick definition, then a longer clinical definition, then sections on epidemiology, what it can feel like, why it matters, how clinicians assess it, treatment implications, related terms, related articles, and sources.
The categories below group entries by the part of care they belong to. The alphabetical strip at the top of the next section lists every entry by first letter for direct browsing. Internal links between entries make it easier to follow a topic from a single word into the wider picture.
Browse by letter
Category
Symptoms
The words in this group describe the experience of depression: how it feels, what it changes, and which patterns clinicians watch. Each symptom can appear in many conditions, but the cluster of symptoms over time is what produces a diagnosis.
Anhedonia
A reduced ability to feel pleasure or to anticipate pleasure.
Read more →Depressed mood
A persistent low mood, with sadness, emptiness, or irritability.
Read more →Emotional numbness
A reduced ability to feel emotion, often described as flatness or distance.
Read more →Fatigue
Persistent low energy that is not relieved by rest.
Read more →Psychomotor slowing
Slowing of movement, speech, and thought that is noticeable to others.
Read more →
Category
Diagnosis and clinical terms
The words in this group are the names of the depression diagnoses themselves and the language clinicians use to describe their course. Knowing the right name for a pattern matters because the right name leads to the right treatment.
Bipolar depression
A depressive episode in a person who has bipolar disorder.
Read more →Major depressive disorder
A clinical diagnosis defined by at least two weeks of persistent low mood or loss of interest.
Read more →Persistent depressive disorder
A long-running form of depression lasting at least two years in adults. Also called dysthymia.
Read more →Postpartum depression
A major depressive episode beginning during pregnancy or in the year after birth.
Read more →Relapse
A return of depressive symptoms after a period of improvement.
Read more →Remission
A period during which a person has few or no symptoms of depression.
Read more →Seasonal depression
Major depressive disorder with a seasonal pattern.
Read more →Treatment-resistant depression
Depression that has not responded to at least two adequate trials of standard antidepressants.
Read more →
Category
Treatment terms
The words in this group describe the treatments themselves: psychotherapy, antidepressants, and the structured care that follows them. Most of these words come up in the first few visits of treatment.
Antidepressant
A medication used to treat depression.
Read more →Behavioral activation
A therapy that uses small, planned actions to rebuild connection to meaningful activities.
Read more →Bupropion
An atypical antidepressant that affects dopamine and norepinephrine signaling.
Read more →CBT
Cognitive behavioral therapy.
Read more →ECT
Electroconvulsive therapy. The most effective treatment available for severe or treatment-resistant depression.
Read more →IPT
Interpersonal therapy. A structured, time-limited psychotherapy that treats depression through the lens of relationships and roles.
Read more →Ketamine and esketamine
An NMDA-receptor antagonist used for treatment-resistant depression. Esketamine (Spravato) is FDA-approved as a nasal spray; intravenous racemic ketamine is used off-label.
Read more →Medication management
The clinical follow-up work after a psychiatric medication is started.
Read more →Psychiatric evaluation
A structured assessment by a psychiatrist or other mental health clinician.
Read more →Psychotherapy
A structured form of treatment with a trained clinician.
Read more →SNRI
Serotonin-norepinephrine reuptake inhibitor.
Read more →SSRI
Selective serotonin reuptake inhibitor.
Read more →TMS
Transcranial magnetic stimulation. A noninvasive, FDA-cleared treatment that uses magnetic pulses to treat depression.
Read more →
Category
Suicide and crisis terms
The words in this group are the language used in crisis assessment and safety planning. They are included because the clear use of these words, in clinic and at home, saves lives.
Active suicidal thoughts
Thoughts about ending one's own life that include intent, a plan, or steps taken toward acting.
Read more →Passive suicidal thoughts
Thoughts about not wanting to be alive, without intent or plan.
Read more →Safety plan
A short, written document created with a clinician that supports safety in a crisis.
Read more →Suicidal ideation
Thoughts about ending one's own life.
Read more →
Browse by article
Most of the words on this page connect to a longer article elsewhere on the site. The symptoms section covers the patient-facing experience of each symptom in the glossary. The types section covers the diagnoses. The treatment section covers psychotherapy, antidepressants, and the broader plan. The suicide and crisis page covers crisis resources, safety planning, and what to expect from a same-day evaluation.
Sources
- American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 5th edition, Text Revision (DSM-5-TR).
- American Psychiatric Association. Practice Guideline for the Treatment of Patients with Major Depressive Disorder.
- NICE Guideline NG222. Depression in adults: treatment and management. 2022.
- National Institute of Mental Health. Major Depression statistics. NIMH, 2022.
- SAMHSA. Key Substance Use and Mental Health Indicators. 2022.
Reviewed by Shariq Refai, MD, MBA. Last reviewed March 15, 2026.